Cold brew coffee in 3 minutes using acoustic cavitation

https://www.unsw.edu.au/newsroom/news/2024/05/Ultrasonic_cold_brew_coffee_ready_under_three_minutes

by ople • 2 years ago

537 351 2 years ago

unsw.edu.au

skrunch• 2 years ago

Quick, someone let James Hoffman know!

blkhawk• 2 years ago

I was just about to suggest he same thing

rolivercoffee• 2 years ago

Don't worry he's way ahead of us: https://youtu.be/2meeYcxXoVs

brotchie• 2 years ago

Coffee fracking IRL

doodlebugging• 2 years ago

Get yourself fracffiened.

simondw• 2 years ago

Ah yes, with a delicious frackuccino.

eps• 2 years ago

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.

seanhunter• 2 years ago

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• 2 years ago

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.

senkora2• 2 years ago

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.

hammock3• 2 years ago

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

dhritzkiv• 2 years ago

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.

nubinetwork• 2 years ago

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

anfractuosity• 2 years ago

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.

bethekind4• 2 years ago

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.

xkcd-sucks• 2 years ago

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• 2 years ago

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

bethekind4• 2 years ago

This had me cackle :D

showerst• 2 years ago

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• 2 years ago

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

sharpshadow3• 2 years ago

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

floatrock• 2 years ago

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.

naltroc• 2 years ago

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

peteforde• 2 years ago

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.

triceratops3• 2 years ago

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.

iancmceachern5• 2 years ago

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.

karaterobot• 2 years ago

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.

Alex3917• 2 years ago

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

kjkjadksj5• 2 years ago

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

hobolord• 2 years ago

There's also this ultrasound company that sells lab equipment, but has a cold brewing via sonification page as well https://www.hielscher.com/ultrasonic-extraction-of-caffeine-...

throwaway482945• 2 years ago

Is their approach different from this one from 5 years ago? https://youtu.be/cO6-SL3bMZg?si=_pVdOLNdej2pjDnT

dahart24• 2 years ago

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.

sharpshadow3• 2 years ago

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.

dahart24• 2 years ago

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.

vallode• 2 years ago

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...

dahart24• 2 years ago

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?

lamename2• 2 years ago

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.

dahart24• 2 years ago

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.

ada19812• 2 years ago

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

90% of the experience is looking cool!

cratermoon2• 2 years ago

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.

SamBam2• 2 years ago

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...

Terr_• 2 years ago

But brew temp and serving temp are orthogonal.

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

eddd-ddde• 2 years ago

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?

opwieurposiu• 2 years ago

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.

dahart24• 2 years ago

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

giancarlostoro• 2 years ago

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.

samcheng• 2 years ago

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.

bobthepanda3• 2 years ago

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.

this_steve_j• 2 years ago

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

tedmiston• 2 years ago

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• 2 years ago

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.

cout• 2 years ago

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.

dahart24• 2 years ago

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.

nkozyra2• 2 years ago

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

YetAnotherNick2• 2 years ago

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.

klausa• 2 years ago

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.

hinkley2• 2 years ago

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.

rrrrrrrrrrrryan• 2 years ago

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.

draw_down• 2 years ago

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

csmpltn• 2 years ago

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

nkrisc• 2 years ago

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

dahart24• 2 years ago

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.

windexh8er• 2 years ago

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• 2 years ago

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.

lytfyre4• 2 years ago

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• 2 years ago

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

CTDOCodebases3• 2 years ago

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

the_optimist• 2 years ago

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

nkozyra2• 2 years ago

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.

bunderbunder4• 2 years ago

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.

dev-tacular• 2 years ago

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.

rpdillon• 2 years ago

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...

bunderbunder4• 2 years ago

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

dahart24• 2 years ago

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• 2 years ago

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.

CTDOCodebases3• 2 years ago

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.

jmilloy• 2 years ago

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.

dahart24• 2 years ago

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.

bethekind4• 2 years ago

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

petre2• 2 years ago

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

SamBam2• 2 years ago

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

D13Fd2• 2 years ago

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 years ago

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.

m4632• 2 years ago

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• 2 years ago

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.

elevatedastalt4• 2 years ago

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• 2 years ago

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.

tracker12• 2 years ago

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

askvictor3• 2 years ago

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.

ccppurcell• 2 years ago

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.

mns• 2 years ago

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• 2 years ago

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.

0xbadcafebee2• 2 years ago

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)

tracker12• 2 years ago

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.

mmanfrin• 2 years ago

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

dahart24• 2 years ago

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.

romafirst33• 2 years ago

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

dahart24• 2 years ago

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.

kjkjadksj5• 2 years ago

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?

dahart24• 2 years ago

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…

solardev6• 2 years ago

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?

Xerox9213• 2 years ago

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.

taylorportman• 2 years ago

Your ambivalence contributes little to the conversation.

ChrisMarshallNY2• 2 years ago

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

King-Aaron• 2 years ago

I like the cut of your jib.

dahart24• 2 years ago

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.

WilTimSon2• 2 years ago

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.

BrandoElFollito2• 2 years ago

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.

chasd00• 2 years ago

somewhere between room temperature and minutes-old vomit

New unit of measure unlocked.

adolph• 2 years ago

moments later I have a perfectly average cup of something

Something about this description brings to mind the tea made by a Nutrimatic machine.

https://www.bbc.co.uk/cult/hitchhikers/guide/tea.shtml

justin66• 2 years ago

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

From the sound of things, Soylent.

https://soylent.com/

insane_dreamer2• 2 years ago

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.

anonuser1234• 2 years ago

You've got a perdy writing style

atoav• 2 years ago

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.

xtiansimon• 2 years ago

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.

anon848736283• 2 years ago

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

blincoln• 2 years ago

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.

_akhe2• 2 years ago

Interesting, microwaving with sound

eschneider• 2 years ago

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.

eezurr• 2 years ago

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

triceratops3• 2 years ago

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

all2• 2 years ago

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.

MisterBastahrd2• 2 years ago

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

bethekind4• 2 years ago

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

MisterBastahrd2• 2 years ago

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.

monkayMan• 2 years ago

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!

pain_perdu• 2 years ago

The longtime CEO/President of Starbucks recently invested in a Cold Brew startup called Cumulus which makes instead coldbrew via a $600 countertop machine.

https://dailycoffeenews.com/2023/11/16/howard-schultz-part-o...

jerlam• 2 years ago

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.

hardwaregeek• 2 years ago

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• 2 years ago

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• 2 years ago

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.

antonchekhov• 2 years ago

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.

beefman• 2 years ago

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...

surfingdino• 2 years ago

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

anon848736283• 2 years ago

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.

knicholes• 2 years ago

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

eichin4• 2 years ago

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" :-)

thsksbd2• 2 years ago

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

askvictor3• 2 years ago

heard an uktrasonicator

Is this a joke?

papertokyo4• 2 years ago

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

bastardoperator• 2 years ago

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

maherbeg• 2 years ago

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

dukeofdoom• 2 years ago

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

lacrosse_tannin• 2 years ago

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

ugh123• 2 years ago

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.

greentxt• 2 years ago

Guess this proves Havana Syndrome is real after all.

LargoLasskhyfv3• 2 years ago

https://en.wikipedia.org/wiki/Sonication

How will cats feel about that high-pitched noise?

cwillu• 2 years ago

    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*!

m4632• 2 years ago

sonicated

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

avidphantasm• 2 years ago

First they should teach Australian baristas what iced coffee is.

eichin4• 2 years ago

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• 2 years ago

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.

eichin4• 2 years ago

Oh, even simpler: cheap sous-vide circulator and rubbermaid "tank" for the outer water bath, tall glass pitcher for the actual coffee, cotton "tea sock" to hold (and filter) the ground coffee in the pitcher. Most of the complication is that it needs to weigh enough (or be braced) so that all of the coffee is submerged, without the pitcher starting to float... and if the pitcher has a neck make sure that the coffee absorbing water and swelling doesn't get stuck inside the pitcher...

0xbadcafebee2• 2 years ago

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

eternauta3k3• 2 years ago

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.

kjkjadksj5• 2 years ago

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

nefrix• 2 years ago

Finally, the scientists discovered a life changing thing.

spython• 2 years ago

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• 2 years ago

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.

cabirum• 2 years ago

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.

acc_297• 2 years ago

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

Spaced-Oddity• 2 years ago

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...

mianos2• 2 years ago

"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.

papertokyo4• 2 years ago

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?

mianos2• 2 years ago

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.

shirro• 2 years ago

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.

klysm• 2 years ago

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

01100011• 2 years ago

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.

conchy• 2 years ago

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.

senderista2• 2 years ago

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.

vletal• 2 years ago

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

nottorp2• 2 years ago

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.

dr_kiszonka• 2 years ago

This is about cold brew, which takes 12-24 hours.

nottorp2• 2 years ago

Yeah so you not only get to set it up, but also check on it a couple times during the day :)

qwerty4561272• 2 years ago

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• 2 years ago

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.

qwerty4561272• 2 years ago

Yes, I think you're right.

ngcc_hk• 2 years ago

Tea as well, said the post.

mattmaroon• 2 years ago

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.

timka• 2 years ago

Hm, I wonder if a ultrasonic nebulizer can be used for that.

Cold brew coffee in 3 minutes using acoustic cavitation

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