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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

#91

Post by aaarrm »

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?

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#92

Post by bethekind »

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…

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

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#93

Post by dahart »

jmilloy wrote: post #84
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…

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 been said many times in this thread, nobody balks at the idea of cold hot brew, nor do they charge extra.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#94

Post by bethekind »

kazinator wrote: post #11
xkcd-sucks wrote: post #8

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

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

This had me cackle :D

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#96

Post by bethekind »

anfractuosity wrote: post #7

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.

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#97

Post by dahart »

ackfoobar wrote: post #89
dahart wrote: post #76

Earlier quoted context omitted.

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.

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

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.

Re: Cold brew coffee in 3 minutes using acoustic cavitation

#100

Post by gruez »

hardwaregeek wrote: post #47

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

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.
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