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Cold brew coffee in 3 minutes using acoustic cavitation

dahart
209 replies
1d3h

Recently I discovered that many coffee shops, maybe half in my sampling of a couple dozen in different cities, are selling cold coffee (brewed hot, then refrigerated) under the name cold brew, and even the ones that actually cold-brew them seem to be under the impression that it needs to be served cold. I was laughed at in one hipster joint for asking for a steamed or warmed cold-brew, and another one initially refused my request to warm it up saying that would make the coffee extremely sour. (It didn’t) Oh, and at least one other, maybe two, said they couldn’t warm cold brew (in view of both a steamer and microwave) or would have to charge extra (while someone’s cheaper latte was being steamed).

Reading the paper, it’s not clear whether their cold brew has lower acidity (higher pH) than the same coffee hot brewed. It does say that the sonic-brew has the same pH as the normal long-steep cold brew. I’m also curious if this cavitation/sonication brewing process is basically agitating the coffee, or doing something different, and how different it is from manually agitating a cold brew compared to letting it sit still for hours.

solardev
45 replies
18h20m

This is why I love my fully automated <s>luxury</s> mediocre espresso maker (https://www.seattlecoffeegear.com/blogs/scg-blog/jura-a1-rev...). I push a button, it grinds the coffee and does stuff inside that I can't see, then moments later I have a perfectly average cup of something resembling burnt bean soup. I don't know whether it's megasonically brewed or absolute-zero infused or just wet caffeine pills. Sometimes it's OK, other times it's mediocre, but it's never been excellent or terrible. That's the same kind of consistency my code has, so I'm fine with it.

It comes out lukewarm, hovering somewhere between room temperature and minutes-old vomit. If I want it hot, I microwave it. If I want it cold, I add ice. If I want a cold latte, I add milk. If I want a hot latte, I'm in the wrong house.

It costs less than $1 for a quad shot. It provides caffeine or at least a close-enough placebo effect. What more could an old, washed-out dev ask for?

ChrisMarshallNY
14 replies
17h5m

Friend of mine, with money, has a coffee machine, by a company I’d never heard of, called “Jura”[0].

I’d not heard of it, because it’s not for plebes, like me.

Grinds and brews a perfect cuppa in about a minute.

I used to have a toddy maker, where you dumped a whole pound of ground coffee into a bucket of water, let it sit overnight, in the fridge, then you drained through a filter.

The resulting thick liquid was like really good instant coffee. You threw a bit into a cup, added hot water, and it tasted great.

[0] https://us.jura.com/en

dc96
4 replies
16h56m

Looks like the comment you replied to links to a Jura as well

ChrisMarshallNY
3 replies
16h44m

Yeah. My friend has one that cost around 3 grand.

The main issue that I would have, is maintenance. I would guess that it would need a fair bit of cleaning.

I just use a fairly basic Braun Melitta filter, and it does great.

solardev
2 replies
16h24m

It's got a decent self-cleaning cycle. Every month or two, it'll ask you to put in a cleaning tablet (about $2 for the OEM version, or there are cheaper generic ones). It goes through an internal cleanse and poops out a slop of muckety muck. I put on soft yoga music for mine, but that's optional. Ten minutes later it's ready to use again.

About half as frequently, it'll also ask you to put in a descaling tablet. Similar process.

Beyond that, day-to-day, it can make about 8 shots of espresso before the grounds hopper is full. You just dump it and rinse it in the sink (no need for a thorough wash) and it's ready to use again. Less cleanup than a regular drip coffee maker (no filters to deal with, no grind dust to rinse/brush, no glassware, nothing to dry).

It's super convenient. The main downside is really just taste. I tried to do a blind taste test with my coffee snob friend (he's the kinda guy who measures everything down to the milligram and gives his grounds acupuncture before sending them to the spa). We used the same bag of beans, same water, same cups, etc. His came out with a layer of fine oils and sparkling foam. Mine looked like someone opened a dishwasher prematurely. We couldn't even get to the taste test part because you could smell the difference with your eyes closed. And I had a clogged nose that day.

Maybe the $3k Jura is different, but my janky little unit is definitely a poor man's machine – the hand-me-down Civic of superautomatic coffee makers. I'd buy it again in a heartbeat though.

rfrey
0 replies
14h26m

I would buy a book of you talking about coffee.

AdamJacobMuller
0 replies
16h4m

Kind of interesting.

I have the Jura Giga 5 and I would say it produces coffee which is better than I can get in any chain store, and, better than the average specialty shop as well. Obviously there are some specialty shops which produce excellent coffee which is better than the Jura, but, not by a massive margin. Interesting that you find the A1 to be much poorer in quality, or my pallet just sucks. Either way I fully agree with you that having "push button, make coffee" is fantastic, I don't want to fiddle with scales and worrying about blooming my coffee grounds for 14 seconds at 92c before brewing with water at 90c. Push button. Make good coffee.

The other "maintenance" item I've noted after having this machine for >10 years is that every 5 years or so it breaks and I have to send it back to Jura.

Their warranty service is a flat-rate $500 and they either repair yours or send you a refurb unit, for something which I spent almost 5k on, I'm very happy that they seem to have the option to basically keep the Jura working forever if I want.

The Giga 5 prefers to listen to the Spotify "upbeat pop music" playlist when I run the cleaning cycle FYI.

beAbU
3 replies
8h46m

We have 2x Juras in my office. They cost a significant portion of my annual salary last time I checked.

Reliable, repeatable, the coffee is not super duper excellent, but it's also not terrible. It's perfectly passable and it's free. My type of coffee.

CydeWeys
2 replies
8h32m

I'm not sure I'd even want a Jura in a home environment. There's so much cleaning and maintenance required! My style is more like good hand grinder (simple, very low maintenance, doesn't take up counter-top space) and an Aeropress and V60 (both simple pieces of plastic, super easy to clean).

It's kind of unavoidable that it's going to be expensive and higher-maintenance to be able to make espresso at home, so I simply don't. Not worth it for me when I already have access to high-end espresso machines at work 5 days a week.

beAbU
1 replies
7h15m

Oh yeah, weekly cleaning cycles, filters, special rinsing fluids and milk tubing that requires daily flushing. Also the machine needs to keep it's water block hot, else the startup time is a few minutes - so constant power draw.

If you have an office where the machine makes 100+ coffees it makes perfect sense. In a domestic setup it makes 0 sense.

CydeWeys
0 replies
7h7m

Yeah, good point on the constant power draw too. I forgot to mention the last bit of kit I use to make my simple at-home coffees: an electric kettle. (And speaking of which, if I ever build my own home, I'm putting 240V counter-top outlets in the kitchen.)

solardev
1 replies
16h49m

That's actually the brand I have, and I'm as plebe-y as they come! I even have a mining pick in my garage that I use for manual labor. I'm nothing like the guy in the photo, more like the guy who makes the coffee for the guy who makes HIS coffee.

You can get Juras for pretty cheap if you go bargain hunting. There are also other similar but cheaper brands. As a category, they're called "superautomatic espresso machines". I don't know why they're not more popular, but it's been a total game-changer for me.

I got my Jura A1 (their discontinued base model) used, third-hand re-refurbished, a decade ago for like $700. A chunk of change upfront to be sure, but since then it's consistently made like 4-8 shots of espresso a day, every day. If reliable mediocrity were a virtue, this thing would be the patron saint of saints. And if a cup of store coffee were $5 (which is cheap nowadays), the machine pays for itself in 3-5 months. Best purchase I ever made.

area_man
0 replies
3h8m

It need not be mediocre. I have a Jura J5 which has, as of this morning, made 18,901 espressos. A few years back, I bought the tool to open it and recalibrated the conical grinder. There are now videos that can walk you through this process.

The mediocrity disappeared. It produces a fantastic brew close to the quality of the shop where I buy the beans.

Before attempting all this, I ran an experiment. I had my shop grind the coffee one notch back from where they grind for their in-house espresso. Then I put that into the by-pass chute and brewed it. This confirmed to me that machine’s grinder was not getting fine enough.

If you grind truly as fine as you would for an espresso machine, you may get a very slightly better brew, but it will come with a 5% chance of clogging the machine and wasting the ground coffee. Best not to fly too close to the sun.

A friend who knows a few things about coffee stopped by not too long after I did this conversion and asked if I had bought new beans, because “this shit is top notch”. It was a revealing experiment about the importance of the grind.

It’s a fascinating machine to take apart. We’ve had it for 15 years and I’m optimistic it will just keep going. At this point my goal it see when the espresso counter will roll over back to zero.

Cthulhu_
1 replies
8h35m

Jura seems to be more aimed at companies (who also have money), we had a few at HQ until we "upgraded" to a full on coffee/espresso machine, the type you see at proper coffee shops.

fch42
0 replies
7h30m

In Germany, Jura coffee machines do come up on the used market frequently enough if you really want one. If you're "lucky" enough to work in an office / for a company that is shutting down, you may get a "sweetened deal" with your layoff ...

Anyway, as others said ... good coffee they make, and some effort on cleaning they need (deserve).

On office coffee machines ... give me anything but syrup post-mix. Douwe-Egberts, I call you out. You make decent machines as well, stop peddling those abominations.

croo
0 replies
12h2m

We have a Jura machine at my workplace since the beginning of time. It brews coffee as good as good the bean you use. After a month it asks for a cleaning cycle which is arcane magic, but other than that it just works and creates its daily 50-100 coffee as usual. I can recommend it, it just works.

taylorportman
5 replies
17h51m

Your ambivalence contributes little to the conversation.

solardev
2 replies
17h16m

Wait till you see my cookbook, "1-minute Meal Replacement Powders", the perfect complement to my self-help/self-sabotage title, "Better Living Through Lower Standards".

YOLO, and no one gets it right on the first try anyway...

toast0
0 replies
15h33m

You may be interested in my philosophy on uptime: nine nines is hard, how about eight eights.

enjeyw
0 replies
16h46m

Are you offering shares in your venture? I’d be mildly interested in investing on the expectation that I’d see returns that are slightly worse than inflation.

Not that interested though, so whatever.

jdlshore
0 replies
16h42m

Whereas I appreciated the unexpected spice, only to quickly be reminded by your comment that, yes, this is HackerNews.

ClumsyPilot
0 replies
17h44m

It represents the same position of mediocre acceptance that many espresso affectionadors will arrrive at after spending many months/years mucking about with expensive kit.

It’s the natural progression of most hobbies

Xerox9213
5 replies
18h3m

But how do you waste time in the morning if you’re not concocting some over complicated drink?

I feel like my morning coffee is the one part of my day that I can control. You bet I’m gonna take my time and make it enjoyable.

kimixa
1 replies
14h14m

I also like the "ritual" of brewing a coffee to help me wake up in the morning. And even then, it's less than 10 minutes total preparing a pour over, it probably takes less time than cleaning out a filter machine would.

And for people thinking you need some $$$ machine, even the most pretentious experts agree that pour over is about as good as that style of brewing can get (IE not something like espresso). A hand grinder and plastic v60 will get you to the point you're not limited by the equipment. The biggest expense is the beans themselves, and that's as much a taste thing as anything else.

But I guess like any hobby you there will be people selling you all kinds of things at any price people are willing to pay - maybe it makes it a bit easier, maybe a bit quicker, maybe it looks better on your counter. Maybe it gives you something a bit different and unusual. But none of it gives you better coffee.

lostlogin
0 replies
10h2m

there will be people selling you all kinds of things at any price people are willing to pay - maybe it makes it a bit easier, maybe a bit quicker, maybe it looks better on your counter. Maybe it gives you something a bit different and unusual. But none of it gives you better coffee.

The Faema e61 Legend isn’t quicker or easier, but damn it is pretty.

And that makes the coffee better. It’s also an effective space heater.

https://www.faema.com/uk-en/product/E61-MONOFASE-ANNIVERSARI...

mesaverde
0 replies
6h13m

I recently dipped my toes into the world of coffee brewing. It all began with a simple realization: I enjoy coffee a lot, so why not elevate my at-home coffee experience from instant to something better?

Using my v60, the slightly longer brewing process has led me to cut down my daily intake to 1-2 (sometimes 3) cups from my previous 4-5.

As a parent with young children, finding time for myself is a rare luxury, even going to the toilet isn't the private sanctuary it once was. Yet, on weekend mornings, I steal away 10-15 minutes to focus on brewing my coffee.

I'm not overly precious or meticulous about it, but the result is a richer, more flavorful coffee. The act of brewing itself becomes a calm and relaxing ritual as I watch the water soak into the coffee grounds and the aroma fills the air.

And its just a good way for me to start the day, before whatever madness and challenges my kids are about to create.

lostlogin
0 replies
10h8m

But how do you waste time in the morning if you’re not concocting some over complicated drink?

Many relaxing things are part ritual. I like your thought process.

jorvi
0 replies
9h24m

I'd say in life you generally want to stick to 20/80 80/20.

Spend 20% in effort and/or currency to get 80% of the optimal result. Spending the other 80% to get another 20% gain is rarely worth it.

WilTimSon
5 replies
8h58m

Well, you're lucky to not have spoiled your palate, in a way. I learned to love good coffee through my friends and I now only drink regular espressos from a machine if there's no other choice. And I'm not being snobby or anything, I fully understand why people drink it, I used to do it all the time. But my friends had to go and teach me about brewing methods and beans and yadda yadda.

Friend of mine had a similar issue where his parents were wine people and, ever since he could drink, taught him how to pick good wine. Except he realised he does not want to pay that much for alcohol so he now just sticks to beer.

benjijay
2 replies
6h14m

I was recently discussing this with a colleague and we settled on calling it quality creep - as you become used to better things, the stuff that was previously acceptable becomes unbearable.

e.g. I used to drink any old instand coffee, then I found Douwe Egberts and strongly preferred that for a few years, then I started making pour-overs with pre ground coffee in a v60, then I found a better grind/roast/etc of the beans which is my go-to - now I drink 'real' coffee black and can only tolerate instant if it's adulterated with milk and a little sugar.

I'm trying to avoid making the jump to pulling my own espressos, it looks like way more fuss than the pour-over...

currency
1 replies
4h45m

Making espresso with my semi-auto Breville Infuser is almost exactly as much fuss as a pour-over:

- Turn it on to heat up - Grind the beans - Weigh the grounds - Fill, tamp, and attach the portafilter - Start the infusion - Remove and dump the grounds - Clean the portafilter

It's a $600 electronic device, not a simple funnel and filter, but it's not a fussy process.

insane_dreamer
0 replies
1h21m

You still weigh the grounds? The difference with eyeballing it is probably too negligible to be noticed.

wickedsight
0 replies
6h47m

Can you try and explain the difference? I've tried many brewing methods and quite like Aeropress, but can't say that I won't like anything else because of it. I also quite like the stuff from my automatic espresso maker, especially if it's just been cleaned.

now just sticks to beer.

Guess he's lucky he hasn't tried good beer ;)

itsoktocry
0 replies
4h43m

ever since he could drink, taught him how to pick good wine.

Except that people who think they can "pick good wine" actually can't (there have been studies, too lazy to Google), and for the most part quality and price aren't correlated.

Luxury beliefs and all that.

BrandoElFollito
2 replies
6h40m

This is more or less what I get as well with my Nespresso machine (it costs 1€, you have to buy x€ of coffee every month which is OK for me). The average cost of a coffee is 0.4€.

The great thing is that it has zero maintenance and zero cleaning. I should probably do some de-limestoning (yes, there is a correct word for that that escapes me now) but I just avoid looking too closely.

solardev
1 replies
2h24m

Totally. I think the Nespressos actually make better coffee. I just wanted something that produced less plastic waste. The only waste outputs of this machine are spent grounds and water (well, and heat). And I can put in any whole beans I like (we just get ours from Trader Joe's), not limited to the Nescafe ecosystem.

BrandoElFollito
0 replies
1h13m

Oh, absolutely. I wanted a zero-maintenance system because I know myself and it would not end well.

My wife was considering a mid-range+ coffee maker where you would have two bean containers and make combinations. It cost a fortune (on my personal scale) and I told her that she lost her mind. And then did an Excel sheet where I realized that the two lines meet at 12 or 15 months...

justin66
1 replies
4h33m

What more could an old, washed-out dev ask for?

From the sound of things, Soylent.

https://soylent.com/

solardev
0 replies
1h42m

Heh, we actually order many boxes of a similar thing (Huel) every month. It's about half of our monthly food intake (by calories).

As a kid I used to dream about being able to photosynthesize. I'd love to never have to worry about food or beverage intakes again.

dahart
1 replies
15h22m

I love that! The context I didn’t put in my top comment but added elsewhere is that this old washed-out dev requires low acidity because regular coffee was causing inflammation in my throat. That’s really all I want, less acid in my coffee, not something fancy. Except that I don’t want it cold, I want it hot like I’ve always had it. Other than that, I’m like you, I’m also perfectly fine with a perfectly average mediocre cup of joe.

IIsi50MHz
0 replies
14h56m

Small amounts of potassium bicarbonate can be used to neutralise the remaining acidity. This helps prevent bitterness, and should not harm other aspects of the taste, unlike sodium bicarbonate. Dissolve into cold water, mix throughly, then add coffee grounds and stir. If you intend to store it, complete absence of light and absence of O2 wild also help prevent bitterness.

insane_dreamer
0 replies
1h38m

Our Breville makes good espresso for 1/4 of the price of that machine. (We have a separate grinder, so it's a semi-manual process to grind each day.) So much depends on the quality of the beans you buy and how you store them.

chasd00
0 replies
6h29m

somewhere between room temperature and minutes-old vomit

New unit of measure unlocked.

anonuser1234
0 replies
1h24m

You've got a perdy writing style

King-Aaron
0 replies
16h23m

I like the cut of your jib.

lamename
42 replies
1d3h

Thank you for saying this. When cold brew first came out, it was promoted as a brewing process that resulted in smoother (I'm guessing lower acidity) tasting coffee. Heating it up seemed natural, and its use in iced coffee seemed simply opportunistic. (In my experience at least).

Then it quickly caught on as a novelty, with nitro et al, and when I tell people I drink cold brew warmed I get looks of confusion or turned up noses.

But brew temp and serving temp are orthogonal.

dahart
26 replies
1d3h

brew temp and serving temp are orthogonal

Yes!!! I’m biting my tongue a little on how infuriating the process has been to ask cafes for warmed cold brews, but you’re spot on and exactly right. I’m baffled that so many people who sell coffee for a living, think they know a lot about it, and act like coffee snobs, don’t seem to understand what cold brew even is. (Or, in a few cases in my sampling I’m certain it was willful ignorance, laziness, because it takes a little more work and more space to cold brew.)

I will say that one of my local cafes understood completely and they’re happy to make hot cold-brewed coffee, and made me feel welcome for asking for it. One or two others were very good about it, but hands down the majority of cafes were a bad experience when asking for a warmed cold brew. Good luck to them, they’ve lost my business.

NoGravitas
11 replies
1d

I’m baffled that so many people who sell coffee for a living, think they know a lot about it, and act like coffee snobs, don’t seem to understand what cold brew even is.

Light roasts came (back?) into style among coffee snobs a few years ago because it highlights the difference between different sources/regions/whatever. Ever since then, the former best coffee shop in my town has been exclusively producing sour, vegetal, under-extracted brews. The justified reaction to Charbucks among coffee snobs has produced an objectively worse cup of coffee.

panopticon
5 replies
23h57m

This is mainly what got me into roasting my own coffee. It was becoming a pain to find high quality dark roasts as all of the boutique roasters turned their efforts to light roasts.

thrixton
3 replies
21h3m

How did you go about roasting your own if you don’t mind me asking.

waldothedog
0 replies
17h17m

I’d recommend getting a stove top popcorn popper and a range hood vent :)

Or if you’re like me and live in an apartment, get a window fan blowing out, and be prepared for your apartment to smell amazing/terrible (depending on your perspective) for a few days

panopticon
0 replies
18h57m

It was a journey! My wife got me a roaster for Christmas several years ago, and I had absolutely no idea how to use it. After tons of reading, YouTube, and trial-and-error I eventually got the hang of it. I still use the same roaster she bought me, but I upgraded to a double-walled chamber to make winter roasting more consistent and temperature probes [1] to record the roast process with Artisan [2]. Since collecting data is fun and makes it easier to get consistent results.

I don't roast beans for cold brew anymore since I drink way too much and it was becoming a chore, but I still roast ~8oz every two weeks for pour overs.

If you're interested there are a lot of great resources online. Sweet Maria's [3] has been a constant go-to for knowledge, equipment, and green coffee beans. And of course, YouTube.

1: https://imgur.com/T0WW90R 2: https://artisan-scope.org/ 3: https://www.sweetmarias.com/

mikestew
0 replies
17h49m

Not OP, but if you just want to experiment and you have a cast iron frying pan, there are instructions out there on how to roast beans with a frying pan. I'll leave the instruction search as an exercise for the reader ('cuz I don't know which ones I used), but basically just keep those beans stirred until they start to pop like popcorn, and you're done. CAUTION: this will make a ton of smoke, as in, if you have a way to do this outside then do it. It's what keeps me from making a habit of it.

That said, much like home-brew beer: best beans I've ever had (granted, I'm no snob). Just writing this makes me want to order a bag of unroasted beans off Amazon and give it another whirl.

Or go the easy route and just order what sibling comment recommends. :-)

sq_
0 replies
20h4m

I hadn't thought of that as part of why finding good dark roasts has been hard for me. I've been annoyed at light roasts for a long time because I tend to find them acidic to the point that they're not enjoyable. I appreciate the bitterness and toastiness of a good dark roast, but finding good ones has been few and far between in my experience.

kibibyte
2 replies
16h25m

Light roasts are great! But there are just a lot of straight-up bad renditions of them, as a result of lack of adequate training on either roasting or brewing, to the consternation of many of those coffee snobs. Unfortunately, this just happens when shops follow trends.

Roasting well in general is already quite challenging and is a lot more than just arriving at a certain bean color or temperature. Vegetal flavors are very much a roasting mistake that's being passed off as an inherent characteristic of a light roast. Combine that with techniques better suited to brewing (or pulling shots of) darker roasted, and you have a recipe for a dull, astringent, sour cup.

That being said, a sour espresso shot is always possible regardless of dark the coffee is, so I'd argue it has a lot to do with a cafe owner's willingness to train themselves and their staff to work with lighter roasted coffee.

cafebee
1 replies
13h42m

What are the variables that a roaster can tweak? Temperature, time, and lots of others I assume? Which variable can produce vegetal flavors? I’d never thought much about roasting but now I’m curious!

lostlogin
0 replies
9h55m

I roast my own with a heat gun.

5 mins or under and it’s scorched, 10 mins or over and it’s baked. I want in the middle.

Too dark and oily and it’s not great. Too light and I miss the bitterness and it tastes weak. I need to stir it a lot or the roast is uneven. I spray water on it at the end to arrest the roasting.

senderista
0 replies
16h47m

Agreed, many supposedly good coffee shops in the Seattle area (e.g. Trabant) produce espresso that is way too sour for my taste. (If you want a point of reference, IMO Espresso Vivace does it perfectly.)

an_aparallel
0 replies
21h22m

i live in Sydney - not far from UNSW :P Campos coffee are phenomenal roaster imo. There's no hype around these light roasts - i would never cold brew them though - i've tried - and it's an incredibly inefficient form of brewing. But light roast itself is a phenomenal thing :)

kurthr
6 replies
1d2h

It's funny cuz Charbux has no problem pouring hot espresso into cold ice milk with caramel and cream on top. I think it's pretty clearly just "baristas" justifying not changing their process, which is fine if a bit lazy and argumentative. Many coffee people are totally interested in finding new ways to do stuff, but they have to have the mental space to do it.

LargoLasskhyfv
2 replies
1d

Funny. Exactly that stuff is the only reason I've ever entered a Starbucks.

Venti!

But TBH one can do that with better coffee, caramel sirup, some crushed ice from the fridge, and even spray cream out of a can for much less money, just not 'on-demand' and anywhere/anytime.

Also, too much (spray) cream and caramel in Venti amounts can't be that good for your body.

waldothedog
1 replies
17h16m

Why not trenta?

LargoLasskhyfv
0 replies
1h21m

Burst prevention.

edit: Also price, the last time I had that it was about 6EUR for Venti, while that even bigger thing would have been just slightly under 10EUR.

Which I think of as insane, considering the not that special ingredients. That was years ago, long before COVID. Didn't go there afterwards, neither in .de, .eur, or the .us. Don't want to support that franchise chain mindfuckery.

look_lookatme
1 replies
22h50m

Starbucks cold brew is actually not bad as far as cold brews go. It’s definitely not iced coffee.

toast0
0 replies
15h26m

They do serve both, and they're different. Close enough for me, so I get the iced coffee cause it costs less and I respond to incentives.

hinkley
0 replies
1d

Pouring hot coffee onto plastic…

WirelessGigabit
4 replies
1d

I’m baffled that so many people who sell coffee for a living, think they know a lot about it, and act like coffee snobs, don’t seem to understand what cold brew even is.

Anecdotally, this is something I've experienced in the USA more than in Europe. When I ask a question in store a lot of times I get the feeling that the person answering considers themselves an expert and quickly make claims that I know for a fact are false.

It's like in the USA saying "I don't know, but let me get someone who does" isn't allowed.

dmix
2 replies
23h28m

You're saying Europeans are less smug than Americans?

Spivak
0 replies
22h18m

It's less about smugness and more that customer-service people are expected to behave like AI and always have an answer whether it's correct or not. I hope at some point we can drop the facade and "I don't know man, I just run the till. Do you want coffee or not?" becomes an acceptable response.

ClumsyPilot
0 replies
17h40m

It’s more about behaving like a chatbot or pre-programmed robot.

If dealing with situation B is not in the manual, they will tell u situation B can’t happen, even if it happening right now.

lb1lf
0 replies
23h58m

   > It's like in the USA saying "I don't know, but let me get someone who does" isn't allowed.
-Anecdotally, I believe this sentiment is inversely related to worker protections - it appears that the easier it is to fire you, the less likely you are to volunteer that you are not at the top of your game at all times.

macNchz
1 replies
23h14m

In my experience having worked in coffee shops, restaurants and bars, there is a considerable overlap between the people asking for something off-menu that nobody has ever asked for, and the people who will never be satisfied with their order.

It might seem like a very simple ask, but I think many people working in those jobs have learned it can be expedient to just say “we can’t do that” and short circuit the interaction, rather than to attempt whatever it is, have the customer send it back, attempt it again and have the customer start insulting them for not being able to “get it right”. This is particularly the case if there’s any sort of line, where one person sending something back will make every other customer angry.

I’m not at all saying you are doing this yourself, just offering context on why you might encounter this reaction.

As in many fields, a fraction of people are kind of awful and unfortunately their behavior winds up shaping how many things operate.

dahart
0 replies
15h32m

I can understand that. I do feel like the reaction I’m sometimes getting is reflexive and not given any thought. My daughter worked at Starbucks for a while, and told me about crappy customers doing this all the time - ordering drinks with questionable modifications and then sending them back when it wasn’t as good as they hoped. Her initial reaction to my steamed cold brew story was that I’m asking for something unusual. For the record, I have never sent back a warmed cold-brew for any reason.

That said, part of what I’m blabbering on about is that I think cold-brew served hot should not be considered off-menu, I don’t think that’s entirely fair. Since cold brew served cold is an assumption in the first place, it seems like hot cold-brew is (or should be considered) just as on-menu as cold-served cold-brew. It’s fine that the assumption exists, I just don’t understand the pushback when I specify warm. I feel like calling a steamed cold-brew off-menu is exaggerating, considering that a) iced coffee exists; b) steaming espresso drinks is extremely common(!); c) many cafes that make espresso drinks essentially offer all combinations of brewing process, coffee, milks of various kinds, and flavorings. It’s so crazy to me to get shit for asking for a steamed cold-brew when something like a Caramel Ribbon Crunch Frappuccino with an Affogato shot and extra espresso exists and isn’t even considered weird or extreme. Maybe some cafes are pushing back against customers with Starbucks expectations, but they still offer a selection like espresso, cortado, mocha, latte, americano, flat white, blah blah blah. It’s like Mexican food, there is a name for every possible permutation of grounds, water, milk, sugar, and heat. Given that they have cold-brew, that they have a steamer, and that serving hot coffee and steaming things are both standard every-day every-order kinds of things, I simply can’t understand why I’d get pushback even if I am asking for something weird. I’m asking for something weird that is completely and trivially doable.

Anyway, you’re right. I know I’m peeing into the wind just a little. It is what it is, which is why it’s a waste of energy to fight it or complain about it. :P

ada1981
6 replies
1d2h

The more complex, expensive and counter intuitive your morning coffee, the better!

90% of the experience is looking cool!

ok123456
2 replies
1d2h

You can buy cold brew coffee at Costco in bulk in cans. Just throw some in the fridge.

klyrs
1 replies
1d

I was excited by this in theory, but it's some of the worst cold brew I've had. For shame, Costco is usually pretty good for selecting quality. Then again, my favorite preparation of cold brew is a shot of concentrate straight from the toddy.

look_lookatme
0 replies
22h56m

I agree. Bought a flat of it a couple of months ago and haven’t drank more than half of them.

lytfyre
0 replies
23h28m

Look, my coffee routine is _perfectly reasonable_.

Fractional gram dosing, multiple pours at different temperatures, timed switch from immersion to percolation, and benchmarking different filter papers has a _measurable impact_ on my coffee.

And I have the data and refractometry measurement data to show it.

... Admittedly the refractometer was expensive, and incorporating it into the routine is complex and not very intuitive.

I can also assure you that I don't look cool while doing it.

kibibyte
0 replies
16h7m

You poke fun at it, but great irony is that a lot of knowledgeable coffee people started poking at all the techniques recently and we've learned that almost everything towards the showy complicated side of it are completely not worth thinking about or will have worse results. Osmotic pouring looks neat but will underextract anything that isn't dark. 4:6 is still questionable over most simpler 1-2 pour techniques. That showy thing of raising the kettle up and down a lot also will underextract.

Y_Y
0 replies
1d1h

Pretension is nine tenths of the law

cratermoon
3 replies
1d1h

As far as I can recall, I've always considered "cold" to apply to the brewing, not the drinking. I learned the technique as "brew extra strong, then add hot water to taste", and that's how I've been doing it since I bought my first cold-brew maker.

Where I live we don't get a lot of hot weather, so drinking cold brew cold is strictly a high summer activity for me.

taude
2 replies
23h36m

me, too. the Toddy brewer 30 years ago, even spoke of this. It was a way to premake your coffee concentrate, and then mix with water and microwave to heat up....

lamename
0 replies
23h31m

This was the first cold-brewing device I ever encountered....as a guest at someone else's house. Didn't know it had a name. Thanks!

cratermoon
0 replies
22h56m

That's exactly the one I started with, and used for years until the plastic got brittle and cracked.

SamBam
1 replies
1d1h

Barismo in Cambridge does (or did) a "hot draft" coffee, that is always on tap, is delicious, and is remarkably like hot cold brew. Their method is apparently a secret (although I'm sure more digging could find it), but I wouldn't be surprised if it wasn't basically on-demand heated cold brew. [1]

1. https://www.baristamagazine.com/the-function-and-future-of-b...

Morizero
0 replies
23h35m

Thanks for the tip, I'll hit them up tomorrow!

eddd-ddde
0 replies
13h58m

I had zero idea that's what it was supposed to be. Cold brew reads to me as brew that is now cold.

Wouldn't it be a better term cold-brew or something like that?

Terr_
0 replies
23h31m

But brew temp and serving temp are orthogonal.

And if anyone doesn't believe this, challenge them to find a truly "iced" coffee. :p

opwieurposiu
26 replies
1d3h

At my friends coffee shop they make cold brew with an elaborate laboratory glassware setup that drips ice-water through a filter. Looks pretty neat and sciencey. They got 4 of these devices running all the time in the back room. I was telling him all the other shops in town just fake it, he should put one of the devices out front so people can see his cold-brew is for real.

bobthepanda
16 replies
1d2h

To be fair all you need to actually make cold brew is a pitcher and a cheesecloth or some other filter. The absence of an apparatus does not make it fake.

bananskalhalk
13 replies
1d2h

Chilling warm brewed coffee is definitely faking it. And I presume all places selling "cold brew" is faking it so this guy is losing money by not showing off doing real cold brew with his apparatus.

janalsncm
9 replies
1d2h

It’s a market for lemons at this point. Unless you can see an expensive apparatus or observe them soaking the coffee, there’s no way to know if it’s correct, and as a customer it means it’s risky to buy if you care about the difference between refrigerated hot coffee and cold brew.

deadlydose
3 replies
1d

Risky to buy? It's not real estate it's a cup of coffee. And if you're worried about people faking it, just buy a $2 mason jar and make some in the fridge while you sleep.

I don't get the fascination with paying exorbitant prices and constantly complaining when it's next to zero effort to make it at home, cold or hot. And the best part is you get to choose where your beans come from, you don't have to worry about the political slant du jour of the coffee shop, and you can do it all for a fraction of the price even when using the most expensive beans.

janalsncm
1 replies
21h8m

Yes, risky to buy. In the same way a slot machine has an expected value of 80-99% payout it’s still a bad use of money even if you only put in $5.

If you object to the word “risky” I used it in the sense of “uncertain you will get the value you expected”. Perhaps there’s a better word.

paulcole
0 replies
8h42m

In the same way a slot machine has an expected value of 80-99% payout it’s still a bad use of money even if you only put in $5.

Why is this a bad use of money? When I go to a restaurant and give them $20 for dinner, it’s not like I’m getting $20 worth of ingredients.

It sounds like you just don’t like gambling?

metabagel
0 replies
20h34m

you don't have to worry about the political slant du jour of the coffee shop

I can't say this has ever been an issue for me. Generally, they just want to sell me some coffee.

rhaps0dy
2 replies
1d

It’s a market for lemons at this point. Unless you can see an expensive apparatus or observe them soaking the coffee, there’s no way to know if it’s correct

Presumably the taste should tell you whether it's correct. Otherwise why care if they fake it?

klyrs
0 replies
1d

I prefer to know what I'm buying before paying for it.

kimixa
0 replies
14h7m

If they "fake it" and it tastes better... then why are you going out of your way chasing some marketing term that tastes worse to you?

majormajor
1 replies
23h41m

Unless I'm a visiting tourist I'm likely to go back to a good coffee shop many times. Being surprised my cold brew isn't cold brew - both the caffeine content and taste are tells IMO - for one visit isn't life or death here. I just don't get it again.

anon84873628
0 replies
3h11m

Caffeine content in the cup is not a good metric. It is one of the most easily extracted compounds and is roughly equivalent across brew types. The beans themselves are a bigger variable in this regard. Even if you are using a roaster's signature blend, the bean composition of that is going to change month to month and year to year. Even beans from the same physical trees will have varying caffeine content depending on agronomic factors.

In the same cafe on the same day, the reason different drinks have noticeably different caffeine content comes down to the different doses and concentrations they end up using. E.g. 20g coffee would normally produce either a 40mL espresso or 12oz drip. So putting that 40mL espresso in a 5oz cappuccino is much more concentrated than a 8oz filter.

bobthepanda
1 replies
1d2h

I’m not talking about chilling warm brewed coffee. All you need to make cold brew coffee is soak coffee grounds in cold water. Whether that is in a mason jar or through a thousand dollar complex laboratory setup is entirely an aesthetic choice.

https://www.loveandlemons.com/cold-brew-coffee/

klyrs
0 replies
1d

My favorite route to camp coffee is running this GSI filter backwards:

https://gsioutdoors.com/products/h2jo-filter

Put a week's worth of grounds in the bottle, screw on the filter, pour in some cold water, steep for 24h, and transfer to another bottle. If somebody wants "drip" strength they can cut it with water, hot or cold.

kjkjadksj
0 replies
21h2m

The way I've seen it done is with one of those massive plastic commercial kitchen lidded containers, and a softball sized teabag of coffee sold by the restaurant supply company specifically for cold brewing like this. Then they put it in the walk in for a while to steep and sell it after a certain number of hours.

enobrev
0 replies
10h59m

French press with cool water over 24 hours is simple and works well.

TrueSlacker0
0 replies
9h26m

100% agree. This is exactly what we do at our brewery and it comes out great. A simple fermenter with a pour spigot works wonderfully (we use this one because we already had it [1]). Soak the ground beans for 12-24 hours in a mesh bag in the cooler, remove the bag and drink on it all week.. or till it's gone.

[1] https://www.ssbrewtech.com/products/brewbucket

this_steve_j
2 replies
1d

Perhaps the Yama cold brew tower CDM25 is the device you saw. It is used at many fine establishments including my kitchen, and I also have the smaller CDM8. The numbers 8 and 25 correspond to the number of cups of diluted 1:1 cold brew that it produces in a single cycle (6-12 hours).

https://yama-glass.com/collections/cold-brew-towers

lytfyre
1 replies
19h12m

If any HNers are looking for a cheap entry point into the style without spending $250+ on a beautiful bunch of laboratory glass ware, there's the puckpuck[1], which sits on top of an aeropress and turns it into functionally the same device as the Yama towers - slow controlled valve dripping cold water at a controlled rate onto a bed of coffee and a paper filter over the course of hours.

I've found it a nice way to play with the style without investing the money and space. Still want one of those towers if I ever see them cheap though.

[1] https://puckpuck.me/ - no connection, just a customer.

samcheng
1 replies
1d2h

I think this is called "Kyoto-style slow drip" coffee. I agree with you that the contraption should be in plain view of the customers!

I remember being really interested in a cup of Kyoto-style one day, only to be told to make a reservation and come back tomorrow... it was worth the wait.

Spivak
0 replies
22h14m

It seems to be a niche taste among my friends, yes it's sour and bitter that's why I like it!

tedmiston
0 replies
23h59m

At my friends coffee shop they make cold brew with an elaborate laboratory glassware setup that drips ice-water through a filter. Looks pretty neat and sciencey.

Likely the Yama cold brew tower [1].

[1]: https://prima-coffee.com/equipment/yama/yamcdm25sbk-yama-pp

shagie
0 replies
15h19m

One that I'm aware of - Black Blood of the Earth - https://www.funraniumlabs.com/the-black-blood-of-the-earth/

Fast forward 14 years. An acquaintance working and living in Japan went on holiday and discovered a bar with this exceptionally beautiful rig for the preparation of Viennese Triple Cold Extraction Coffee. Upon sampling this, he felt that, and I quote, “I could see colors that weren’t in the visible spectrum, and could vibrate through walls.” I looked at this I said to myself, “Hey, you’ve got enough virgin laboratory glassware lying around the house that you could probably build something like that.” Probably several somethings, actually, but that’s beside the point.

It has a picture of the original glassware in Japan and his first iteration in the kitchen. A sibling comment links to Yama glass ... which is out of Taiwan. The similarities might not be coincidence.

giancarlostoro
0 replies
1d3h

I would literally go to a shop doing this, like as often as possible. As a coffee lover, this is peak coffee shop.

He could even double down and make Breaking Bad references around the shop, since thats what this makes me think of.

I'm guessing it's not in Florida, or I would ask you for the address. He should at least get a window into that backroom installed or something to that effect.

dahart
0 replies
1d3h

That is awesome! I would absolutely love it if more cafes did this. Let us know where it is so we can go patronize.

csmpltn
13 replies
1d2h

This is an extreme form of coffee hipsterism. “Cold brew, but steamed please”. Brother, this is starting to get ridiculous.

dahart
5 replies
1d2h

My doctor recommended cold brew for lower acidity, because hot brew is bothering me. Cold brew is just a brewing process and has nothing to do with serving temperature. Cold brew has never meant served cold. So what, exactly, is ridiculous about warming up cold brewed coffee? I like my coffee hot, like a lot of people, and I’d like it if I can keep drinking coffee and don’t have to stop due to the acidity.

ackfoobar
2 replies
1d1h

It might be obvious but I have to ask, is that a stomach problem?

dahart
0 replies
1d1h

Not for me, but it is for some people. My current issue is more esophageal, my throat gets inflamed with too much acid then it feels like I have food stuck and can’t swallow it. Other people have stomach issues, ulcers, etc. but still want to enjoy coffee, so I think there’s plenty of reasons for cold brew served hot to exist.

aaarrm
0 replies
1d1h

Not the person you are asking, but I do have GI issues due to the acidity with coffee. It can cause reflux, ulcers, and more for people if they are sensitive to the added acidity.

sushid
1 replies
22h9m

I'm a coffee snob and I can respect your preferences but have you considered non-coffee alternatives? Japanese and Chinese tea culture can be fun to delve into and tea would probably be easier on your stomach.

dahart
0 replies
21h36m

I definitely have considered alternatives, and do drink tea, more now than before, in part because of my negative experience experiences trying to get hot coffee that was cold brewed. Finding the fake cold brew many places really scares me off cold brew more than baristas who don’t want to heat the coffee. Single shot americano is another alternative with a bit lower acidity, I believe, and even with that I often get mild push-back from baristas… “you sure?? We pull two shots anyway…”

The main problem is that I love the flavor of coffee, and I feel especially jealous on a Saturday morning when I can smell it but can’t drink it. Secondary problem is adjusting to a consistent caffeine level without getting headaches.

nkrisc
1 replies
1d2h

It’s no different than drinking an iced coffee drink that was made from coffee brewed traditionally.

dahart
0 replies
1d1h

That’d be true if putting ice in coffee reduced its acidity. Heating cold brew brings a lower acidity liquid up to a nice warm good morning temperature.

windexh8er
0 replies
1d

For people who are accustomed to cold brew (we always have cold brew in the fridge and grounds steeping) there's a very large difference in flavor and profile using the same beans. This also translates when it's heated, although I will say I don't do that often because I enjoy it cold more than hot.

I'd disagree though that it's "extreme". There are local chains in my area (Midwest - US) that offer a variety of hot cold brew drinks that are quite popular offerings. I was pleasantly surprised when I ran across this more than a year ago. But I still do run into a number of coffee shops where baristas fail to understand the difference between cold brew and an iced coffee. There's really no comparison when you're explicitly looking for cold brew. It's also often hard to find available in the winter months in my region. Not sure why, but to me that's akin to pausing ice cream sales because there's snow on the ground. Just because it's a cold drink doesn't mean I don't drink it during cold weather.

surement
0 replies
23h39m

extreme form of coffee hipsterism

I know a lot of coffee nerds and cold brew is disdained for not extracting enough flavors. This is just someone who never adapted to the world hoping the world will adapt to them.

lytfyre
0 replies
18h54m

Wouldn't knock it till you try it! The drink kinda had it's moment a couple years ago - "Aerocanos" or "Steamed Iced Americanos" are the names I've heard for the drink. Often made with the kind of post-brew chilled cold brew that OP was railing about. Cold coffee, steamed to frothy, then either pour over ice to re-chill or serve warm.

Wouldn't try to randomly talk a barista into making one, but if you see them on the menu at a shop or have an espresso machine, they're pretty neat.

Video on them: https://www.youtube.com/watch?v=tD_4hOg_SWU

everettp
0 replies
12h8m

Would you say that a discussion about GPU densities was an "extreme form of processing hipsterism"? Unless your contention is that there is no observable difference between the types of drinks described by OP, this comment is an embarrassing ad hominem and has no place here

CTDOCodebases
0 replies
6h10m

Don't knock it till you try it! It tastes even better with a twist of lime.

elevatedastalt
12 replies
23h55m

The emperor really has no clothes when it comes to food fads.

And pricing is a completely orthogonal and obtuse concept too. Cold brew is putatively low effort and low cost. Just let coffee grounds soak in water overnight and you have cold brew. But it's often charged more than regular coffee or espresso-based drinks, which a) use more expensive equipment b) need more skilled operation c) more material [milk etc]

fwip
5 replies
23h8m

Speculation:

Cold brew takes more refrigerator space, which is relatively inflexible. Since it brews overnight, you have to put aside enough fridge space for all the cold brew you expect to sell that day. Contrast with regular coffee, which you make largely on-demand, with only the coffee beans to store overnight, on a shelf. So raising the price might be the sensible thing to do, to discourage purchases and/or pay for the extra refrigerator space.

elevatedastalt
3 replies
23h0m

That's a good point. From what I understand, cold brew can be made at room temperature too. So it will need storage but not cold storage. But it's possible I don't have the full picture.

Bluecobra
2 replies
21h57m

I have found no difference in just using cold water and having it sit on my counter overnight vs. keeping in the fridge. It is nice to still refrigerate it to use less ice or no ice though. In a retail setting, I would think customers would demand a cold product (I would). The Starbucks near me serves Nitro Cold Brew and for some reason it's always warm/room temp, and they purposely do not put any ice in it. Other locations seem to not have this issue so maybe it's broken equipment or training.

stephenhuey
0 replies
21h45m

Cold brew coffee is by definition not brewed with hot water the way most coffee is (in other words, room temperature is within the range of "cold" when talking about brewing with "cold" water). So, it's not necessary for it to be served cold to enjoy the benefits of the cold brew method--sometimes I like it chilled, but I also enjoy the taste at room temperature or warmer.

elevatedastalt
0 replies
21h2m

Cold brew is so much more caffeinated that I've seen most shops add tons of ice to create enough drinkable volume without giving you enough caffeine to knock a horse down.

CTDOCodebases
0 replies
6h20m

That's true. Also there are too ways to approach it: 1. Brew as much as you would use on a busy day and price in wastage in case it doesn't all sell. 2. Brew a small amount and price it higher so that only a small amount needs to be sold in order to turn a profit.

tracker1
1 replies
22h52m

As to C, that applies to cold brew just as well as hot brewed coffee.

elevatedastalt
0 replies
22h17m

Possibly, but I've seen cold brew served mostly just by itself or just some syrup / cream, as opposed to cappuccinos / lattes which need much more milk.

mns
0 replies
3h20m

That's not necessarily true. The coffee to water ratio for cold brew can be generally lower, and you end up needing more coffee for 2-3 cups. At home, using something like a Hario cold brew bottle, and depending on how much coffee you use, I would say it's anywhere from 20% to 50% more expensive than a standard V60 brewed coffee.

In a coffee shop you need to prepare way more coffee, you need the space to store it cold over night, so I would say the higher price is understandable.

joshfee
0 replies
2h47m

The mistake here is thinking that cost and price are related beyond determining what the final margin is.

The consumer decides the price that is acceptable for the good - the cost of that good being higher or lower just changes the viability of the product and the bottom line from selling it. So it makes tons of sense that given two similar products that consumers will pay a similar price for that companies would prefer to sell the one that costs them less.

ccppurcell
0 replies
3h40m

Pricing is not at all obtuse! Or no more than any other product on earth. It costs what people are willing to pay. Your estimation of the value takes into consideration what you believe (I'm not saying you're wrong) the costs to be, and good for you. But until people are unwilling to pay, the price will go up.

askvictor
0 replies
21h10m

Cafes often charge more for niche items, mainly because they can. There's also the workflow of the barista to consider - leaving the espresso machine to get ice from the freezer disrupts the flow of constantly pumping out lattes.

dev-tacular
9 replies
1d2h

Does cold brew served hot taste good? I have never really considered asking for it hot before simply because I thought it would just be like regular coffee. But, I guess if regular coffee tastes different cold and hot, cold brew should too.

bunderbunder
4 replies
1d2h

Yes. The major reason for cold brewing coffee (or tea!) over simply cooling and icing hot brew is that you extract a different mix of compounds from the bean (or leaf) due to different chemicals having different levels of solubility at different temperatures.

Serving temperature affects flavor, too, of course. Darn near everything does.

See, for example: https://www.mdpi.com/2304-8158/9/7/902

marcoalopez
3 replies
1d1h

This is only partly true. Because low-temperature extraction is much less efficient, it requires a much longer immersion/exposure time than hot extraction at ambient or slightly higher pressure. One of the effects of this type of cold extraction is the oxidation of the coffee, which is much greater with this method, giving the coffee an oxidised taste which, although not bad in itself (nothing is set in stone about personal taste), is not to everyone's liking. For my taste, I prefer to make it hot (with a higher coffee/water ratio than usual) and cool it down by diluting it with water or ice.

bunderbunder
2 replies
22h59m

Definitely. Though the oxidation seems different? I don't find cold brew to taste "stale" the way hot brewed coffee that's been stored overnight in the refrigerator does.

I have a bunch of kegging equipment that I don't use anymore because I've lost my taste for beer, and I keep wanting to see what happens if I use it to make cold brewed coffee under a bed of CO2.

Also, y'know, coffee on tap at home.

eternauta3k
1 replies
22h28m

Won't the CO2 make the water acidic?

bunderbunder
0 replies
3h29m

Nitrogen is better, but the equipment is more expensive and finicky. CO2 under just enough pressure to keep the oxygen out shouldn't dissolve into the liquid too much, though.

The downside is that you then couldn't use gas pressure to push the liquid through the tap line, but you can use gravity or a beer engine instead.

rpdillon
0 replies
1d2h

Cold brew is much less acidic, and I find warmed cold brew to be exceptionally smooth compared with hot brew. I got my recipe from a NYT interview with the CEO (I think?) of Blue Bottle, though I've since lost the link. This is my copy:

https://rpdillon.net/recipes/new-orleans-cold-brew-coffee.ht...

dahart
0 replies
1d2h

Tastes good to me. It is like regular coffee, just lower acidity, which is what I need. I want it to taste the same as regular coffee! ;) To be fair, it usually tastes milder than how brewed coffee, and this is one of the things people like about cold brew.

HankB99
0 replies
1d

Good is subjective. I've trialed cold brew at home and have been serving it warmed. I prefer my coffee hot. I thought it tasted fine, different but neither better nor worse than hot brew (drip in my case.)

Since it's DIY I have no one to argue with about how to serve. I have stopped making cold brew for the most part because it seems to require more coffee beans than hot brew. Maybe I'm doing it wrong. I don't have a "cold brewer" and just add water to grounds in a glass jar with lid and shake when I walk by before filtering it the next day. Neither have I compared the cost of electricity for drip vs. the extra beans for cold so I don't really know which is more cost effective.

CTDOCodebases
0 replies
6h0m

I think people like it because it has less acid.

AFAIK the aromatics in coffee are quite volatile so what you end up with is like "grain soup". The coffee tastes more like the roast than the actual coffee.

cout
9 replies
1d2h

As I understand, the serving temperature of coffee does have an effect on perceived acidity (which is NOT the same as pH), though I don't understand the science behind it. Here is one paper that claims it is due to release of volatiles at higher temperatures: https://www.sciencedirect.com/science/article/abs/pii/S03088...

If that's correct, then warming the coffee again to that temperature would again speed up the release of volatile compounds, though what effect that might have on flavor is anyone's guess.

rrrrrrrrrrrryan
1 replies
23h54m

As a complete layman, when I tried tossing cold brew into the microwave it ended up tasting pretty gross. Like, jarringly so.

I won't pretend to know the science behind it, or perhaps I warmed it differently than what the parent poster does, but I definitely sympathize with the barista's hesitation in his story.

ch4s3
0 replies
22h24m

Yeah, there are still a lot of dissolved coffee solids in cold brew that get further extracted if heated. There are also a lot of volatile compounds that break down when heated. The idea that you can just reheat coffee, even cold brew and have it taste the same is just ridiculous.

klausa
1 replies
1d1h

Isn’t that a pretty generic and well known (and not coffee-specific) effect, that flavor is pretty temperature dependent?

Warm Coke is disgusting; freezing cold Diet Coke is the nectar of gods.

parpfish
0 replies
1d1h

room temp soda is my favorite. there's so much more flavor when it's not cold.

however HOT cola (which can happen if you leave it in a car) is physically painful because something weird happens to the bubbles

YetAnotherNick
1 replies
1d2h

Also, in my experience heating the coffee in microwave increase perceived acidity even more. Which kind of make sense with this explaination as there could be pockets of superheated water when it is microwaved.

eternauta3k
0 replies
22h31m

Could you try giving it a good stir right before putting it in the microwave?

nkozyra
0 replies
1d2h

Ah, just posted that I detect a change in flavor after I heat cold brew (but didn't know a mechanism behind it)!

hinkley
0 replies
1d

Cold brew isn’t about pH, it’s about bitters. The oils aren’t (just) acidic, they’re bitter, and that’s what you don’t get when you make real cold brew instead of failing it.

Acetic acid is sour. Alkaloids are bitter.

dahart
0 replies
1d2h

I could buy it, that it might have some perceived effect that’s measurable. I have tasted many a warmed up cold brew, and it tastes like coffee to me. The ones that are actually cold brewed are milder, and the hot brewed fakes are noticeably sharper, and I feel it later in my throat… The thing for me is that the actual acidity of coffee has started causing some inflammation. The reason I’m seeking cold brew is my doctor recommended it. I’m less worried about the perception of acidity and more worried about issues caused by too low pH.

jmilloy
8 replies
1d1h

Everything you say makes sense, with the exception of your expectation not to pay extra for an unusual order (for that cafe). Consider if I asked for my salad to be roasted, and balked at a surcharge on the grounds that they also have roasted brussel sprouts! I don't think it's up to you to decide what orders fit into their flow and which cost extra. I'm glad you found the places that will make the coffee the you like.

dahart
7 replies
1d1h

It’s not an unusual order, hot coffee is sold millions of times per day, and steaming comes with many coffee drinks, it’s par for the course with espresso drinks. Roasting a salad is weird, hot coffee is not, so your example is straw man. The “cold” in cold brew is not referring to serving temperature, that’s your own misunderstanding, so I find the suggestion that hot cold brew is weird to be pretty funny. As has been said many times in this thread, nobody balks at the idea of cold hot brew, nor do they charge extra.

shawabawa3
3 replies
1d1h

But hot cold brew is weird, as you've just been complaining about people not doing it or finding it weird

If hot cold brew was common you wouldn't pay extra for it

dahart
2 replies
23h31m

The biggest sticking point is not the heating of the coffee at all, it’s the widespread misunderstanding of the what the word cold means in the term “cold brew”. It is incorrectly assumed that brewed relatively cold (room temperature) means served ice cold. Somehow a lot of people can’t understand the verb brew has nothing to do with serving temperature. Does that make sense to you?

papertokyo
1 replies
19h14m

Although you are entirely correct in a technical sense, and it's common to serve hot brewed coffee cold, the opposite is so rarely desired that it will be considered 'weird' (in the sense of 'unusual') 9 out of 10 times.

Every extra process involved in making a coffee is going to add complexity and time to the workflow, which many cafes will elect to charge extra for.

There is some consternation in Australia about paying more for iced coffees compared to hot ones too:

https://www.broadsheet.com.au/national/food-and-drink/articl...

dahart
0 replies
15h28m

I know, I know. You’re right. But… even if it is weird, it is so easy! It’s not really the default assumption that’s frustrating, it’s when I get push-back for a request that is normal and default for other espresso drinks, something trivially doable, something every barista does dozens and dozens of times a day.

artimaeis
2 replies
1d

Former barista, it _is_ an unusual order from the perspective behind the bar. Unusual in that I never have heard of someone ordering a warmed cold brew.

I'm not certain how I'd warm it up. I suppose it could be poured into a clean frothing pitcher and steamed directly, I'd somewhat worry that might dilute the flavor of the coffee.

I don't reckon someone's going to want me to microwave their cold brew, but it certainly seems like it'd be the quickest way to do it.

Most cafe workers get into flows of orders. Lattes means you always pump syrups into the cup, start the pour, then steam milk. Cold coffees usually means you ready the cup (syrups, milk) and pour the cold brewed coffee onto it.

Warming the cold brew totally breaks that flow, and is why it would be unexpected.

Hope that perspective helps. I do want to try it now though! I could imagine it being pretty good.

lytfyre
0 replies
19h1m

Coffee nerd, I like to play with this stuff. Steaming cold brew (flash or regular) will give a very smooth frothy texture - almost nitro like foam. You can serve them over ice to get them back to cold, or serve warm.

Tasty if you use good coffee, and pretty unique honestly - "steamed iced americano" or "aerocano" are the two names I've heard if you want other people's reports on them.

You're right that it's very different from the experience of microwaved cold brew, and a customers response can be all over the place depending on what they're expecting.

dahart
0 replies
23h57m

I appreciate that, it does help, thank you. Indeed I found a few cafes that were used to it, and quite a few that weren’t. I think you’re totally right that this trips up some people’s flow especially when they’re not used to it. I’m okay with accepting it actually is unusual for some and just instead being the person complaining that it should be usual or expected even if it isn’t always. FWIW I have tried it microwaved, and it’s fine, but never in a cafe - baristas have always steamed it until warm or hot. That also works for me.

vallode
5 replies
1d3h

The paper[1] seems to imply agitation is exactly what this method is promoting: "Furthermore, acoustic streaming induced greater mixing and enhanced mass transfer during brewing.". I assume the 100W of ultrasonic energy would be pretty hard to reproduce by just shaking your cold brew container though!

[1]: https://www.sciencedirect.com/science/article/pii/S135041772...

dahart
4 replies
1d3h

Very interesting, and I missed the 100W bit, thanks! Yeah that would be really hard to do by hand for 2 minutes. Maybe Guinness records needs to see who can shake their cold brew hardest/longest. So this begs further questions for me, like can I shake with 10W for 30 minutes, or 10 minutes, or…? Does the frequency matter? Can we use one of those chem lab agitator machines to cold brew?

petre
1 replies
1d2h

Yes, it's the frequency and also the amplitude that makes it faster. One could use a lab agitator but it would still be too slow. I think if you pour the water into an ultrasonic cleaner along with the coffee and filter the mix you might get the same result.

fch42
0 replies
7h25m

That's precisely the thought which has taken hold of me now as well.

The ultrasonic cleaner is always stashed away somewhere safe for its once-a-year use ... I think can't resist to experiment.

kurthr
0 replies
1d2h

I find it interesting that 100W for ~120 seconds is ~0.3kcal which for a 100ml cup is ~3C. They are right at the limit of power to flow rate. Much faster flow and presumably the cavitation wouldn't "brew" enough, while much slower and it would warm up the coffee noticeably. I'm doubtful the frequency matters much if the cavitation is what is causing the mixing since those are just bubbles emerging and popping, but the efficiency of coupling from ultrasonic wand to liquid could change a lot.

Since you could presumably put 2 of these in parallel and have 2x100ml cups in 2min with 200W without changing the recipe (or 1 cup in half the time), this seems pretty scalable with increased cost and area.

Unagitated cold brew is in the 10hour region, but with agitation/pump through it seems like you can do 8 cups in 20min which is almost as fast as the cavitation method. I suspect the grind size starts having really big effects here.

https://instantpot.com/products/instant-cold-brewer

aaarrm
0 replies
1d1h

I think the size of the vibrations is important here. The paper mentions acoustic cavitation, which I believe would only really occur at small frequencies like the ones stated in the paper, not large shakes that you or I would do.

mmanfrin
3 replies
21h21m

I was laughed at in one hipster joint for asking for a steamed or warmed cold-brew

Not to discount the rest of your comment but it's a mild irony here for you to add the 'hipster' qualifier to a coffee place when you ask for steamed cold brew

dahart
2 replies
20h52m

Why’s that? What’s ironic? Do you feel like that’s a fair gotcha? Do you know why I asked for a heated cold brew?

I’m asking for cold brew because my esophagus gets inflamed with higher acidity coffee. I used hipster not as pejorative, but to indicate this is a cafe that claims to, and should, know the difference between cold brewed and hot brewed coffee. In fact, I’m certain the owner does know the difference and the snarky barista who refused to help me that day does not. First she said, “Uh, we call that a drip.” When I offered the acidity reason and that it’s my doctor’s recommendation, she replied with “it’s not on the menu”. Cold brew was on the menu.

omnimus
1 replies
9h51m

Sounds like you are the snarky hipster. The barista didnt know this process and didnt have it on menu. In their eyes its just strange request asking for trouble.

I think of myself as very knowledgable barista and this is first time i am hearing this. I checked usual resources like James Hoffman and nobody is even mentioning heated cold brew. So its very niche and sounds more like something from camping.

I believe you that health wise its for some people better. But cold brew overall is not that popular with coffee fans because the coffee is underexttacted - it tastes ok but you will get more flavours using hot water. Its kinda waste to use high quality coffee on cold brew. But thats where i personally like cold brew - with lower quality coffee it can taste better than hot extraction.

dahart
0 replies
4h31m

WTF? I don’t understand the attacks. Where in the exchange do you see snark from me? I wasn’t rude to her, nor to the parent and she absolutely was rude to me, and so was parent and so are you now. Why? Did my use of hipster trigger people, or was it something else? It’s fine if she doesn’t know what warm cold brew is. She didn’t say she doesn’t know how to make it. She did know how to make it, but instead of making it, she took the time to insult me for asking.

Cold brew was in fact on the menu, and it is in a lot of cafes. Arguing that cold brew is not popular and not ideal is a straw man here, and is also very debatable given that it’s widely available. That cold brew was available and on the table is a given, regardless of what you think about it.

You say you are a knowledgeable barista. Can you handle steaming something? I’m pretty sure you can, and that it would be 100% trivial, right? I didn’t ask for some unknown or mysterious or strange process. What I asked for is pour the cold brew they were selling into a cup, and steam it. Exact same process as the milk half of a latte. Why, exactly, does it matter what’s being steamed, and why does that deserve scorn when requested? Why, exactly, does it matter if the request seems unusual? Who cares, when you and I both know it can be done without even thinking?

The good cafes do it happily without batting an eyelash, and don’t complain about it being weird, because if you think about it at all, heated cold brew might be uncommon but it’s neither weird nor hard to do at all.

D13Fd
3 replies
1d1h

I drink only cold brew normally, and I've noticed this as well. It's 50/50 whether you will get actually cold brew at any given coffee shop or just iced hot-brew coffee, which tastes different and has much less caffeine.

Cold brew needs a new name or it will likely fade away over time.

fuzzzerd
2 replies
22h27m

There's nothing wrong with the name cold brew. It describes the difference from "standard" coffee. It is the charlatans selling warm brew over ice that devalue it.

As someone that greatly prefers coffee brewed cold and served on ice, I hope it doesn't fade away, because without it I have a lot less reason to get coffee out as opposed to at home.

dahart
0 replies
21h20m

There shouldn’t be a problem with the name, but my experience tells me that people don’t comprehend it the majority of the time, and assume incorrectly that cold brewed must be served cold. This mentality is even here in this thread in a few places. It does seem like some other word than “cold” might help avoid leading people into an erroneous conclusion.

D13Fd
0 replies
18h8m

Yeah I greatly enjoy cold brew too. But it's too easy for people working these stands to just take any old coffee that's cold (or even just "not hot) and call it "cold brew." Far too often people just don't know the difference and serve plain iced coffee.

If it were called something else, maybe there wouldn't be this level of confusion, or people couldn't get away with the cheap/lazy way of just serving yesterday's leftover hot coffee as "cold brew."

sharpshadow
2 replies
1d3h

I think they mentioned that cold brew has lower acidity than hot brew.

Yes it’s agitation with the mentioned frequency. Technically it should move the grounded coffee particles back and worth and so extracting the components.

dahart
1 replies
1d3h

Yes, they mentioned that cold brew has a reputation for being lower acidity than hot brew, but they didn’t measure the pH of the coffee they were testing using a hot brew process. They reported the pH of the normal cold brew and sonicated cold brew as both about 5.1.

For frequency, does it matter if it’s high or low frequency? I’m wondering if I can shake my cold brew for 3 minutes and get close to the same effect.

sharpshadow
0 replies
23h22m

Yes hot brew coffee has more acidity tan cold brew. I like hand filter coffee and I use water around 90 degree Celsius. The higher I go with to boiling water the more it washes out bitter and acidic components.

petre
2 replies
1d1h

That reminds me of the Soul Kitchen movie when a client of a fancy restaurant asked for a hot gazpacio. The waiter escalated to the chef who calmly explained to the client what a gazpacio is. After the client insisted, shouting at him, the chef refused driving his knife into the client's table.

https://youtu.be/rQ61MfRBSQg

SamBam
1 replies
1d1h

We had gazpacho soup for starters... I didn't know that gazpacho soup was meant to be served cold. I called over the chef and told him to take it away and bring it back hot! So he did... the looks on their faces still haunt me today! I thought they were laughing at the chef, when all the time they were laughing at me as I ate my piping hot gazpacho soup! I never ate at the Captain's table again. That was the end of my career. – Rimmer, Red Dwarf

https://www.youtube.com/watch?v=3ZGJHDegPcU

aspenmayer
0 replies
22h22m

Red Dwarf is one of the most unhinged shows I’ve seen, in the best way. Nice reference, as I was also thinking of hot gazpacho soup, but had forgotten this scene until you reminded me of it.

kjkjadksj
2 replies
21h7m

I wonder if you can deal with the acidity issue in a quick and dirty manner by just throwing in some baking soda into your grinds and brewing hot?

dahart
1 replies
16h1m

Okay this is a totally wild and hilarious coincidence, but I came home tonight and told my wife about this thread. Turns out that, today of all days, without knowing I was ranting about cold brew on HN, she did a careful home experiment with her coffee using baking soda, so I can report on what she found. She has suffered me complaining about fake cold brew and rude baristas before, but it’s been months since we discussed it. We do have some pH test strips sitting around from my investigations into different brewing methods, and she used 4 of them doing this experiment twice.

For each experiment, she made 2 cups of coffee, using 1 scoop of grounds (0.25 oz) to make a pour-over with 8 oz water heated to 200 degrees Fahrenheit for each cup. In one of them she added 1/16th teaspoon (which is a tiny pinch) of baking soda to the grounds before pouring the water over them. In the other cup, it was only grounds with no baking soda. She said she could see the water foaming in the cup with baking soda. She reported that there was no noticeable negative flavors at all, no hint of baking soda taste, the coffee made with baking soda was as good as the control, perhaps slightly better because it was less acidic. For the pH measurement, she measured a pH of 6 for the normal coffee and a pH of 8 for the baking soda added cup — it actually made the coffee slightly alkaline! PH of 6 sounds like a pretty weak coffee, I was usually getting a pH of 5 IIRC. PH strips are a pretty blunt measure and don’t give you fractional pH values, but she showed me the strips and I can confirm her conclusion. The 2nd experiment was the same setup, and the result was identical.

When I read your comment earlier, I thought it was a good question, but assumed baking soda would change the flavor negatively. I’m surprised to hear that it totally works, so I think you have a good idea. I might even consider making this my routine if it works that well. Now I’m curious if you can sprinkle in a tiny pinch of baking soda into an already brewed coffee and reduce acidity without damaging flavor…

bobthepanda
0 replies
12h39m

I suppose this makes sense? Baking soda’s main flavor profile is bitter, but coffee is already bitter so I suppose it isn’t going to make things worse. (Compare this to its use in baking, where you have to be careful not to use too much so the bitterness doesn’t ruin the baked good.)

romafirst3
1 replies
21h13m

All coffees tend to be in the same ph range regardless of brewing technique.

dahart
0 replies
1h17m

This contradicts the common claims about cold brew. Do you have any references on it? When I google it now, the first answer I get says hot brewed gives a pH around 4.8 and cold brewed around 5.1, which if true is a 2x difference in acids. My home tests with pH strips show drip and pour overs to be a bit more acidic than a very fast aeropress.

There are low acidity beans, and as I just found out additives to counteract acidity that won’t compromise the flavor, such as baking soda. I guess I might head more in that direction and stop worrying about cold brewing.

nkozyra
1 replies
1d2h

I find that heating cold brew reintroduces some of the flavor of hot brewed coffee, though I've never been able to pinpoint a mechanism for it.

bunderbunder
0 replies
1d1h

Speculation: A lot of it is that chemicals that contribute to flavor are more volatile at higher temperatures.

The same things happens with beer. Many traditional and craft beer styles are intended to be served at a higher temperature than what it will be right out of the refrigerator, and you really do get more (and, to my palate, better) flavor out of them if you let the bottle warm up on the counter for a while before you open it.

m463
1 replies
23h58m

I've been doing cold brew for a while now.

There seems to be two ways to cold brew coffee.

The more traditional method (like in the toddy system) uses paper filters, and the newer method uses reusable metal filters.

They are slightly different. the paper filters remove the oil, while the metal filters let it through. I suspect this might have flavor/aroma effects.

I also read because of the oils, the metal filter method is higher on cholesterol (if that makes any difference to you)

I've also seem drip cold brewers at some coffee shops that probably let the oils through. There seems to be a container of ice at the top, it melts and drips on a glass container of coffee and that drains through a circular glass thing (looks like a slinky) into an output carafe.

throwaway2037
0 replies
8h39m

I did a double take here:

    > higher on cholesterol
As I understand, cholesterol only occurs in animal products. That is why vegan diets are cholesterol-free. Zero trolling here: I assume that coffee beans are animal-free.

Google tells me:

    > Though brewed coffee does not contain actual cholesterol, it does have two natural oils that contain chemical compounds -- cafestol and kahweol -- which can raise cholesterol levels. And studies have shown that older coffee drinkers have higher levels of cholesterol.

xtiansimon
0 replies
6h40m

Hipster coffee is not all the same. My local farmer’s market has a coffee seller who cold brews super strong coffee, then adds hot water—delicious.

tracker1
0 replies
23h2m

I like, and use the term "iced cold brew" for serving cold... not sure about serving cold without ice... In that my first introduction to it, the person would be taking it from a container in the fridge, adding some water and microwaving it to heat it up.

After trying it, I liked it a lot... I always drink coffee over ice (usually with a lot of cream and sweetener), as I'm not so much a coffee fan as a caffeine consumer a few times a month. I like the more mellow taste of cold brew.

the_optimist
0 replies
1d2h

“Old Brew” can be more valuable. You must check the vintage and terrioir.

draw_down
0 replies
1d2h

I agree people can be really annoying about heating up cold brew. Iced espresso no problem, heated cold brew = mind blown.

bethekind
0 replies
1d1h

Using low frequency sound will agitate the solute and solvent, speeding up the natural cold brew process.

Using ultrasonic will do it even faster, but since ultrasonic underwater induces cavitation bubbles, it's much more violent.

Ultrasonic has been used for dermal infusion quite successfully, but it is....painful, as bubbles are exploding against your skin.

I would presume the same to be for the sonic coffee. Agitation speeds up the process, until cavitation occurs, where it becomes more violent

atoav
0 replies
11h53m

As someone who regularly makes cold brew during hot summers, the tale is that the acidity is lower — or at least of a different kind.

Hot brewed coffee starts to taste bad after a few hours if you let it go cold, cold brewed coffee tastes differently from the start, but won't develop that bad flavour even after a week in the fridge.

The key for a good cold brew is however that the bean/roast is of very good quality. And it is quite simple to make. The way I do it:

1. Grind coffee coarsly and put it in a glas jar that can be closed. The amount of coffee can be adjusted quite freely, but I'd go with one fourth/fifth of the volume of the jar. More bean = more concentrated coffee.

2. Add cold water and stir

3. Put in the fridge and stir at least once in the morning, once in the evening.

4. After ca. 24 hours you can run the whole thing through a coffee filter to extract the coffee. It is also possible to reuse the coffee-sludge once if you add some fresh beans.

That is not too complicated and worth a try. Please avoid pre-grind cheap coffee for this, It will taste like bullshit.

anon84873628
0 replies
3h15m

And yet if you asked for the "aerocano" as seen on YouTube, they would probably be happy to oblige.

0xbadcafebee
0 replies
23h25m

Flavor compound release is affected by method, temperature, and wat. The method (which includes temperature, but is not restricted to it) extracts certain compounds. The release is affected by temperature and the amount and type of compounds in solution. It's entirely possible that warming up a cold-brewed coffee could create off-flavors.

If you let coffee and water sit for long enough, all the compounds that can be extracted, will be extracted. But those compounds will also start to break down over time. Heating and oxidation accelerates the breakdown.

When you go to taste coffee, the compounds in the coffee either expand or contract depending on the temperature, and solubility. So the temperature you drink it at, along with water concentration, determines the flavors. (Flavor is actually aroma, taste only has 5 basic senses)

peteforde
18 replies
1d3h

Funny thing is that I'm currently drinking cold brew that I prepared on my acoustic cavitation brewer.

It's called Osma Pro. The company that made it sadly did not survive, and they took a lot of heat (no pun initially intended) for the price point and various complaints about how it worked.

https://www.engadget.com/osma-pro-cold-brew-coffee-machine-r...

Luckily, mine works great and I like it a lot. I use it every morning.

Takeaway point: maybe Google your idea to see if other people have also had it before describing it as new.

triceratops
14 replies
1d3h

The system connects a bolt-clamped transducer with the brewing basket via a metallic horn – transforming a standard espresso filter basket into a powerful ultrasonic reactor.

Now it can be done without shelling out $695 for a dedicated machine. That's progress. I wouldn't be so dismissive.

iancmceachern
12 replies
1d3h

But you have to shell out $10k for a commercial ultrasonic welder from Branson, etc. Just the horn they show in the paper probably cost $6k to make.

I wouldn't be too dismissive.

fallat
7 replies
1d3h

What? I went on Aliexpress and found a 40KHz transducer for $40. You can 3D print the attachment, can't you?

iancmceachern
6 replies
1d3h

A woofer from AliExpress is not a speaker with amp you can use for University level audio work.

I expect they used something like these:

https://www.emerson.com/en-us/automation/branson

You cannot 3d print anything in the ultrasonic chain, they need to be machined from specific metal, that's why the horns cost so much.

parineum
2 replies
1d2h

A woofer from AliExpress is not a speaker with amp you can use for University level audio work.

We're talking about coffee here...

iancmceachern
1 replies
1d2h

Exactly!

Wars have been fought over coffee, people regularly spend thousands for coffee machines. There are entire companies that exist just to cater to this market.

Me, I'm a tea guy.

JoBrad
0 replies
23h44m

A wholly different set of wars

fallat
2 replies
1d2h

I looked up "transducer" and it seems to be what you'd need. But! You seem to have found where I was wrong: the horn. The horn seems to be the actual expensive part here. They could start a business I guess selling these en-masse. If anyone has any ideas how a maker could create this within reason please reply.

iancmceachern
1 replies
1d2h

You can't really sell them in big quantities because they're typically custom to the task. They need to be custom shaped for each application.

srmatto
0 replies
23h58m

Portafilters are made in mass so you could make horns for common portafilters.

bongodongobob
1 replies
1d

They make ultrasonic jewelry cleaners for $75 that should work just fine. You're referencing something that is intended to be used with hundreds of gallons of water.

iancmceachern
0 replies
23h8m

I'm just talking about the paper. If they had referenced what you mention I would have referenced that

triceratops
0 replies
1d3h

It's a prototype.

daniel_reetz
0 replies
1d3h

Also it will be punishing for pets and MEMs microphones.

karaterobot
0 replies
1d1h

However, engineers from UNSW have now developed a new way to make cold brew coffee in under three minutes – just like a regular hot brew – without sacrificing on the taste experience.

I think the commenter you're responding to was calling out the use of the word 'new' (which is used five times in the article) to describe the process, when it's evidently not new at all. The commenter didn't say anything about the price point, and neither does the article.

kjkjadksj
0 replies
20h59m

$695 isn't even bad, have people seen what even an entry level espresso machine can cost?

Alex3917
0 replies
1d3h

I hope the creator does another run of the original Sora Pot, I would buy that in a heart beat.

seanhunter
14 replies
1d4h

This is awesome in an overengineered way, but if you want to make cold brew the normal way it's very easy. Basically you make it using a cafetière/French press/Bodum[1] using cold tap water in the fridge overnight (probably put some cling film over it), then press it and run it through a drip filter. The secret (if there is one) is to use fine ground coffee like you would use for an espresso rather than coarse ground (like you would use for a normal drip coffee or French press). It's very easy and very lovely. Just don't skimp on coffee.

More detailed recipe here https://www.uncarved.com/articles/cold-brew/

[1] UK/US/French name but you know the thing with the plunger

arijun
11 replies
1d3h

If you use a French press for cold brew, be aware that the harder you press, the more bitter it will come out.

I use a $5 nut milk bag instead, it lets me brew way more at once; I do 1/4 kilo grounds with 2 liters of water. It also has the benefit of reducing cafestol, which makes it healthier, according to some.

hammock
7 replies
1d2h

the harder you press, the more bitter it will come out

Huh? I don't plunge until after it brews, and the purpose of the plunge is just to keep the water out of the grounds from that point forward, to (essentially) stop the brewing process. Or so I thought

i_am_jl
4 replies
21h36m

Plunging pushes your coffee through the metal filter. Pushing harder pushes the coffee through the filter with a higher pressure. Higher pressure pushes particles past the filter more easily than lower pressure. Coffee particulate has a tendency to make coffee more bitter.

Anything that gets more small particles past your filter will add to your coffee's bitterness. This can happen when using a ground coffee that has a lot of fine particles, or if you agitate when you pour/plunge.

hammock
3 replies
21h0m

I don’t know anyone who’s jumping up and down on the plunger or doing anything more than pressing it slowly. Have to imagine the coarseness/evenness of your grind is a 10x bigger factor in that regard

NegativeLatency
2 replies
20h43m

or doing anything more than pressing it slowly

I have a french press for camping, it's fine but when I want that first cup of coffee and it's cold and rainy outside you better believe I'm not pressing it slowly.

hammock
1 replies
18h22m

Three seconds faster? You must really like coffee

NegativeLatency
0 replies
17h30m

Hm maybe not that fast, whats considered fast?

vincentrolfs
0 replies
1d1h

I agree with your confusion, are we all talking about the same thing?

bschmidt1
0 replies
18h31m

I used to plunge down hard and fast because I liked to see the bubbles.

But I realized less disturbing is better, and I started barely using the plunge - just to catch grounds when pouring.

After a while I went back to pour-over. The flavor is so much better - French press is now used for loose leaf tea and I have a lot more fun plunging.

senkora
2 replies
1d3h

It also has the benefit of reducing cafestol, which makes it healthier, according to some.

I often filter my french press cold brew after-the-fact with a paper filter to achieve this.

base698
1 replies
15h40m

Isn't the paper filter supposed to strip flavorful oils? Which negates using a French press?

senkora
0 replies
13h45m

Probably. To be honest I just find it convenient to use a French press as a cold brew maker and first-pass filter, because it is IMO easier to keep clean than a nut milk bag or coffee sock.

nubinetwork
0 replies
13h32m

I just pour coffee grinds into a recycled pop bottle... no need to get fancy with a French press.

dhritzkiv
0 replies
21h41m

One thing I'll mention is that cold brew doesn't need to be put in the fridge to "brew". It can be left out on the counter at room temperature. As a result, this takes the brew time from 24 hours to about 12 hours.

thsksbd
4 replies
1d2h

I'm guessing few on this board have heard an uktrasonicator in action.

I just showed to article to my mate, and he enthusiastically said we'll brew some... as soon as we leave the lab to break for lunch

askvictor
3 replies
21h8m

heard an uktrasonicator

Is this a joke?

papertokyo
2 replies
18h36m

No. These machines sound like robot hornets operating dental drills.

askvictor
1 replies
17h13m

I thought ultra sonic was defined as being above the sonic range of humans. Genuine question: why would an ultrasonic noise generator create sound audible frequencies? Can it not provide enough power without doing so?

thsksbd
0 replies
14h25m

Ultrasonicators for the purpose of cavitation research are insanely powerful and non linear material response cause all sorts of vibrational modes to boom.

Its unpleasant.

showerst
4 replies
1d3h

This is incredibly cool and I want to go build one, though it feels like that cutaway model of injecting the ultrasound from the side would lead to very uneven extraction.

I also chuckled at graf about doubling the caffeine content, as if that's necessarily a good thing =).

Those cheap HC-SR04 ultrasonic modules output at 40kHz, so maybe this is home-brewable.

htrp
3 replies
1d3h

I think the idea is that the vibration transmits through the entire filter. The question is whether it's geometry/frequency specific

floatrock
1 replies
1d3h

The embedded youtube video at 0:58 shows a laptop screen with some pretty fancy-looking simulation jiggles and heatmaps on what looks like an espresso filter.

It also looks like a PDF of a paper, so presumably they have a paper that talks about the geometry/frequency interactions.

eichin
0 replies
22h24m

The article includes a link to the paper, which has simulation models of the acoustics, showing pressure levels and areas where cavitation can occur. (I didn't see anything about heating from dissipating the acoustic energy, though?)

sharpshadow
0 replies
1d3h

It’s likly not specific one could reduce the cold brewing time by shaking the jar.

brotchie
3 replies
1d4h

Coffee fracking IRL

doodlebugging
2 replies
1d3h

Get yourself fracffiened.

simondw
1 replies
1d3h

Ah yes, with a delicious frackuccino.

papertokyo
0 replies
18h34m

I'll have two frack whites to go thanks.

xkcd-sucks
2 replies
1d3h

It's really just a matter of mindset -- Many things go faster if you chuck them into a microwave or a sonicator :) I'm definitely going to try this out with cold brew in a cheapie bath sonicator. The thing here is like a big ass probe sonicator butted up against an espresso portafilter which is probably a bit louder than a loud steamer

kazinator
1 replies
1d3h

I have two sonicators, aged 3.5 and 5.5. The older one is going into grade 1 in September.

bethekind
0 replies
1d1h

This had me cackle :D

skrunch
2 replies
1d4h

Quick, someone let James Hoffman know!

blkhawk
0 replies
1d4h

I was just about to suggest he same thing

qwerty456127
2 replies
11h5m

You can also make reasonable (not excellent, not terrible) brandy this way by putting vodka and oak wood shavings of a suitable kind into an ultrasound machine.

robocop_legacy
1 replies
4h13m

I think it would be similar to an aged whiskey, perhaps. Brandy is distilled from wine. Bourbon is primarily from a corn mash, so maybe with the right vodka.

qwerty456127
0 replies
2h45m

Yes, I think you're right.

mianos
2 replies
20h29m

"Ultrasounds can be applied to several areas across the food industry including drying, extraction, emulsification and crystallisation – making the process faster and more efficient.", .. I think they have the tense wrong. It should read "Ultrasounds are now commonly applied .."

People have been doing this sort of thing for years. I have an ultrasonic tub for extracting flavours into ethanol. I didn't invent it, people were talking about it years ago on the forums on this stuff.

Maybe they don't have internet over there at UNSW. They can come over and borrow mine for a bit of a search. I am just a few ks away. Or go to that internet cafe in Kensington in the next block.

papertokyo
1 replies
18h41m

The innovation here is integrating the tech into a home espresso machine package. I do wonder if the sound is any less awful though.

Does the ultrasonic tub enable better extraction at lower proof or are you using it purely to speed up the maceration process?

mianos
0 replies
16h14m

The ultrasonic tub, (Vevor LOL, like everyone else gets for their bike parts), speeds up the process, specially oak shards.

For comparison, I also have a Soxhlet apparatus. As the extraction is boiled in the bottom with the recycling solvent it does not make the best flavours but it's the fastest way to get stuff like cinnamon.

Between a longer time, soxhlet and ultrasonic, the ultrasonic gives flavours as smooth as a longer time without the wait. (The ultrasonic bath heating up is still a problem so I have to cycle it).

Time beats both.

I think a short path soxhlet maybe be as good. My setup is a bit fragile for a good vacuum though.

hardwaregeek
2 replies
1d2h

This is a neat idea, since cold brew has a common criticism of an oxidized flavor due to its long steep time. A shorter steep could get you the smooth flavor without the oxidation

gruez
1 replies
1d1h

Wouldn't it be cheaper to brew the coffee in a sealed/vacuum chamber instead? Whatever machine they're using to generate "acoustic cavitation" doesn't sound cheap.

quarkw
0 replies
20h46m

That was my first thought. It seems like others have already tried it with good results.

https://old.reddit.com/r/coldbrew/comments/ob0gzg/cold_brew_...

You can also sous vide coldbrew coffee for faster results than traditional coldbrew. But at that point is it still technically coldbrew? Maybe warmbrew is a better term for it.

eezurr
2 replies
1d3h

I discovered you can mix Nestle instant coffee with cold (charcoal filtered) water and it dissolves fine. Somehow the added sugar easily dissolves too. I also add heavy cream

It actually tastes pretty good. Most of the acrid taste from (hot) instant isnt there

triceratops
1 replies
1d3h

But then you miss out on the self-flagellation aspect of drinking instant.

all2
0 replies
1d3h

You can no longer mutter to your coworkers I just need the caffeine as you add the 5th scoop of instant to your Styrofoam cup of hot water.

MisterBastahrd
2 replies
1d3h

Anyone ever tried dumping coffee grinds and water into an ultrasonic jewelry cleaner?

bethekind
1 replies
1d1h

Wattage might not be high enough to notice a difference, but might be fun

MisterBastahrd
0 replies
23h46m

So I looked at Amazon for products. There's an ultrasonic brewer that is used for both cold brew coffee and also for rapid infusion of spirits with charred barrel staves. There's also a stir plate / french press combo for sale that apparently does fine cold brew in 20 minutes.

0xbadcafebee
2 replies
23h33m

So, to simplify, we could take a large mason jar and attach to the bottom a magnet and wire coil attached to a power source, and just pump sound waves into a glass jar of water and coffee grounds. Effectively it's a speaker that holds coffee. Should have the same effect

kjkjadksj
0 replies
20h57m

Buy an ultrasonic cleaner off the shelf and just decant the grounds out of the coffee when you are done

eternauta3k
0 replies
22h18m

If the cavitation really is important then no, it won't have the same effect. But maybe the cavitation is not important! Try it out and report back.

surfingdino
1 replies
1d2h

James Hoffman's video on the subject incoming in 3... 2... 1... can't wait :-)

anon84873628
0 replies
31m

He's already spoken many times about cold brew. including his preference for iced filter as opposed to true cold brew. which may have contributed to the exasperation expressed in the current top comment.

Maybe the Coffee Lit Review podcast will cover this, but honestly it's not that interesting. Cavitation has already been done many times.

spython
1 replies
22h26m

Or you could use a (quite affordable) ultrasonic machine designed for gentle cleaning of jewelry, dentures, glasses..

I've used one to extract fragrance from biological material for an artistic project[0], and it worked really well. Instead of having to wait for a few weeks for a tincture to finish, you put the same tincture (alcohol and material you want to extract fragrance from) into a plastic bag for just 15 minutes. Sure, it smells not quite the same, but the speed is often worth it. I've even heard about some guy trying to turn vodka into whiskey with an ultrasonic machine and wood chips.

There are quite a few ultrasonic machines on the market. I've tried EMAG and multiple Chinese no-name machines that are just as powerful but cheaper. Sadly the no-name machines are quite a bit louder - you can't stay in the same room while it's running basically. Still, they all work well for this kind of fast and dirty extraction.

[0] https://rybakov.com/blog/smelling_cz/

19f191ty
0 replies
2h56m

This is what I was thinking. If it's mostly fine scale mechanical agitation one is after then there are many ways to do it. An ultrasonic cleaning machine being the closest in spirit to their approach.

jerlam
0 replies
1d

The machine uses single-serve, single-use aluminum pods, which along with the machines are expected to be available next summer.

Of course, it's an attempt to be the next Keurig/Nespresso.

knicholes
1 replies
1d2h

Does anyone know what make this better than just stirring for three minutes?

eichin
0 replies
22h21m

The paper lists many things they tested for, but the fascinating one is that the coffee oils and water get emulsified which isn't going to happen with any level of stirring below "purée" :-)

eichin
1 replies
23h49m

Ooh an excuse to upgrade some homelab equipment :-)

(My preferred "weird" coffee is sous-vide: 125g/liter, 2h @ 150f - so you don't leave as much flavor "on the table", but by not getting near boiling you leave more of the bitter compounds behind. Refrigerated but served iced or warmed with boiling water, to taste.)

manishsharan
0 replies
3h15m

I would like to try this. Are you using ice cubes to vacuum seal or do you have some fancy gadget that I must have !

We need Lance Hendricks or James Hoffman to do experiments and determine the best temperature.

blincoln
1 replies
1d3h

I'm disappointed that their test didn't include a comparison to traditional drip coffee made using the same beans, then chilled to match the temperature of the cold brew.

I haven't looked into ultrasonic cavitation in years, but since it can produce enough heat and light to make some people wonder if it was a form of nuclear fusion back in the early 2000s, I feel like maybe it's affecting the flavour of the coffee at least as much as using hot water would.

bschmidt1
0 replies
12h12m

Interesting, microwaving with sound

anfractuosity
1 replies
1d3h

Interesting, I wonder how that would compare to recirculating water through the coffee grounds through a filter.

It does say the ultrasound generates 'micro-jets with enough force to pit and fracture the coffee grounds', so I assume that the ultrasound would work better?

There also seems research in using ultrasound in artificial ageing of whisky/spirits.

bethekind
0 replies
1d1h

A YouTuber calls thought emporium tried out the whiskey method

And yes, ultrasonic cavitation will break apart the grounds very thoroughly. Think a jewelry or denture cleaner.

vletal
0 replies
16h45m

Can I just take an ultrasonic jewelry cleaner and fill it with water and ground coffee?

ugh123
0 replies
1d1h

Here's my iced coffee prep for those who like it strong with a bite:

Prepare a "lungo" via espresso by brewing through twice (or more) as much water through a single espresso puck. Don't do this over ice. Put the cup in the freezer. Depends on the cup (I use ceramic) but should be close to room temperature or slightly cold after about 30 minutes. Now pour over ice.

Can also do this over night for larger brews in the fridge (non freezer).

This is as close as I could get to a Starbucks iced coffee that isn't watered down and still has bite.

shirro
0 replies
20h2m

Wake up yourself and all the dogs in the neighborhood at the same time. I want one.

I went through the obligatory Australian fascination with espresso and am well over it. It is a load of fetishistic bs and scalding hot coffee is disgusting. I buy bottles of cold brew from a local roaster and avoid the hassle.

senderista
0 replies
16h50m

Our espresso machine has been on the fritz for a while, but I barely miss it after discovering that a few oz. of TJ's cold brew with a splash of milk in the microwave for 30s is practically as good. I think warmed-up cold brew is one of my favorite life hacks.

selimnairb
0 replies
23h53m

First they should teach Australian baristas what iced coffee is.

nottorp
0 replies
11h54m

Why 3 minutes? Fancy ways of brewing coffee bring more value via their ritualistic part than via the final product. Same for smoking a pipe, it's the filling up and cleaning that matters.

If you want speed, get a fully automatic machine. Ideally with a timer so your coffee is ready when you wake up.

ngcc_hk
0 replies
9h37m

Tea as well, said the post.

nefrix
0 replies
23h31m

Finally, the scientists discovered a life changing thing.

naltroc
0 replies
1d3h

Two of my favorite things, cold brew and acoustics :D

monkayMan
0 replies
1d3h

I enjoy a good cold brew but it’s been a rare occurrence. It usually has a stale taste I assume is due to oxidation. I can see coffee shops using acoustic cavitation to make fresh batches throughout the day instead of one big overnight batch!

mattmaroon
0 replies
6h51m

It’s strange that they write this like it’s some new discovery when modernist chefs have known this for years and even developed “sonicators” for commercial use.

maherbeg
0 replies
1d1h

Huh, I'd love to taste a sample. This would be such a nice extension to an existing Espresso setup!

m463
0 replies
1d

sonicated

I sense a new term making its way into coffee marketeering...

lacrosse_tannin
0 replies
1d1h

In the picture, it looks like they're posing with some refreshing sun-tea. Maybe they should try 4 minutes.

klysm
0 replies
18h58m

Ultrasonics seems like a heavily underused technology based on the little I know about it. Piezo elements are cheap too and you can get a lot done with them

greentxt
0 replies
1d1h

Guess this proves Havana Syndrome is real after all.

eschneider
0 replies
1d3h

Technically interesting and possibly useful at an industrial scale, but I think I'll stick to my moka pot/french press setups. Both are good enough and easy enough for me.

eps
0 replies
1d4h

Was going to crack some joke about their work, but then realized that this tech is absolutely monetizible. Hook it up to, say, Nespresso marketing machine and this will sell like hotcakes.

dukeofdoom
0 replies
1d1h

They should add led lights and ultrasonic vibration to the cup for a futuristic cyber punk style presentation.

cwillu
0 replies
1d

    The Doctor: It's sonic, okay, let's leave it at that.
    Captain Jack Harkness: Disruptor? Cannon? What?
    The Doctor: It's sonic, totally sonic. I am sonicked *up*!
    Captain Jack Harkness: [yelling] A sonic *what*?
    The Doctor: [yelling] *Coffee maker*!

conchy
0 replies
17h38m

As someone who makes cold brew every day, this is one of the two approaches I've considered to speed things up, the other being one of those magnetic stirrers they have in chemistry lab. However, after careful consideration, the real low-hanging-fruit here is the time it takes to grind the coffee, load it, fill the water, clean the filter, and rinse the jar. If a cold brew machine could automate these steps (like some hot coffee machines do) you wouldn't care about making a cup in 3 minutes because you'd always have an automatic jar ready for you from 24 hours ago.

cabirum
0 replies
22h8m

Search for "portable ultrasonic washing machine" on Amazon/Aliexpress, looks like a hockey puck you drop into a bucket with water and clothes. Looks like the principle of operation is the same, just add a coffee filter.

beefman
0 replies
1d2h

A few years ago there was a crowdfunded instant cold brew machine based on acoustic cavitation called Osma.[1] I don't think it's still in production. I met the founder during testing at Chromatic Coffee in San Jose, and took delivery of one of the first units. Cool concept, but it didn't work very well

[1] https://www.engadget.com/osma-pro-cold-brew-coffee-machine-r...

bastardoperator
0 replies
1d1h

Whatever they're holding up in that picture, it looks more like iced tea versus cold brew coffee.

antonchekhov
0 replies
1d2h

New startup idea: manufacture a hard-plastic spiky attachment, shaped like a tubular hair-brush that I can simply screw onto the base of my Sonicare toothbrush, then stand upside down into the brewing carafe of my Oxo cold-brew setup. The Sonicare's built-in 2 minute timer may have to be activated twice, for a full brew.

acc_297
0 replies
21h48m

unfortunate that the acoustic cavitation frequency is just barely within the range some dogs can still perceive

Spaced-Oddity
0 replies
20h43m

Not to be that guy, but this works with room temperature water if you stir it for a minute as well. No need for "acoustic cavitation" for this to work.

The inventor of the aeropress shared this tip. Here's his recipe:

https://www.youtube.com/watch?v=oUD6HxDnlwI&t=56s&ab_channel...

01100011
0 replies
17h57m

Hmm.. I didn't think to try my ultrasonic machine. Last time I made cold brew and got impatient, I just warmed it up to around 100F and put the whole thing in my vacuum chamber for a bit. Seemed to speed things up but I don't know. I don't brew enough to have a recent comparison. The result is pretty great though.