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Cold brew coffee in 3 minutes using acoustic cavitation

unsw.edu.au

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Re: Cold brew coffee in 3 minutes using acoustic cavitation

#71

Post by petre »

dahart wrote: post #44
vallode wrote: post #27

Earlier quoted context omitted.

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...

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?

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#72

Post by hammock »

arijun wrote: post #19
seanhunter wrote: post #6

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…

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.

>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

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#73

Post by janalsncm »

bananskalhalk wrote: post #55
bobthepanda wrote: post #50

Earlier quoted context omitted.

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.

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#74

Post by rpdillon »

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.

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...

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#75

Post by YetAnotherNick »

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…

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#76

Post by dahart »

csmpltn wrote: post #53
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…

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

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#78

Post by bunderbunder »

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.

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

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#79

Post by dahart »

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.

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#80

Post by ok123456 »

ada1981 wrote: post #58
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…

The more complex, expensive and counter intuitive your morning coffee, the better! 90% of the experience is looking cool!

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