Cold brew coffee in 3 minutes using acoustic cavitation • Hacker News Board

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#121

Post by HankB99 » Tue, May 07, 2024, 5:48 PM UTC

dev-tacular wrote: post #70

dahart wrote: post #17

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 refus…

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.

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#122

Post by cwillu » Tue, May 07, 2024, 5:53 PM UTC

    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*!

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#123

Post by NoGravitas » Tue, May 07, 2024, 6:02 PM UTC

dahart wrote: post #40

lamename wrote: post #32

Earlier quoted context omitted.

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 turne…

> 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 w…

> 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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#124

Post by artimaeis » Tue, May 07, 2024, 6:07 PM UTC

dahart wrote: post #93

jmilloy wrote: post #84

Earlier quoted context omitted.

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 lik…

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 be…

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#125

Post by hinkley » Tue, May 07, 2024, 6:08 PM UTC

cout wrote: post #46

dahart wrote: post #17

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 refus…

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 re…

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#126

Post by rhaps0dy » Tue, May 07, 2024, 6:11 PM UTC

janalsncm wrote: post #73

bananskalhalk wrote: post #55

Earlier quoted context omitted.

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.

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.

> 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?

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#127

Post by klyrs » Tue, May 07, 2024, 6:13 PM UTC

bobthepanda wrote: post #61

bananskalhalk wrote: post #55

Earlier quoted context omitted.

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.

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/

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#128

Post by klyrs » Tue, May 07, 2024, 6:15 PM UTC

rhaps0dy wrote: post #126

janalsncm wrote: post #73

Earlier quoted context omitted.

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.

> 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?

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

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#129

Post by jerlam » Tue, May 07, 2024, 6:15 PM UTC

pain_perdu wrote: post #45

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...

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#130

Post by WirelessGigabit » Tue, May 07, 2024, 6:19 PM UTC

dahart wrote: post #40

lamename wrote: post #32

Earlier quoted context omitted.

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 turne…

> 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 w…

> 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.