Using Sound Waves To Make Espresso Could Cut Coffee-Brewing Energy Use By 75% (theconversation.com) 26
Researchers developed an ultrasonic espresso process that uses high-frequency sound waves instead of hot water to produce espresso-strength coffee at room temperature. And, not only did coffee drinkers find it comparable to traditional espresso, but the brewing process cut energy use by up to 75%. An anonymous reader quotes a report from The Conversation: We have developed what we call an ultrasonic espresso: a room-temperature brewing process that uses high-frequency sound waves to extract the flavor, oils, aroma and caffeine from coffee grounds. The result is an espresso-strength coffee made in under three minutes, but needing far less energy than the conventional method. Saving up to 75% of energy by not heating the water is a minor benefit for home users or small coffee shops. But for companies making ready-to-drink coffee products at industrial scale, it could be very significant indeed. A concentrated room-temperature coffee could be used directly in bottled drinks, milk-based beverages or cold coffee products. It can also be shipped as a concentrate and diluted later. This would reduce not only energy use, but potentially processing time as well.
The key to the new process is ultrasound. These are sound waves above the range of human hearing. In our system, a small metal device called a transducer presses against the side of a traditional espresso basket and makes it vibrate rapidly. Those vibrations move through the water and coffee grounds. This creates a phenomenon known as acoustic cavitation. Tiny bubbles form and collapse in the liquid. When these bubbles collapse near coffee particles, they produce microscopic jets and forces that act a little like scrubbing brushes. They pit and fracture the surface of the coffee grounds, helping flavor compounds, oils and caffeine move into the water much faster than they normally would at room temperature. In other words, ultrasound helps us replace heat with mechanical energy.
[...] In earlier work, we used ultrasound to speed up cold brew dramatically. But the challenge in this project was different: could we produce something with the strength, body and intensity of espresso, without heating the water? To do that, we adjusted several variables. Brew ratio was one of the most important: how much water we used for each gram of coffee. Too much water and the drink becomes diluted; too little and extraction becomes difficult. Grind size also mattered. Finer grounds allowed us to extract flavor more rapidly. Finally, we tested how long the ultrasound should be applied. We found the sweet spot was about two-and-a-half to three minutes. Of course, making a concentrated coffee in the laboratory is one thing. The real test is whether people want to drink it. [...] For the espresso samples, participants could not reliably tell the traditional and ultrasonic versions apart. There were no significant differences in aroma, flavor, bitterness or overall liking. For filter coffee, the ultrasound version was actually preferred overall, with participants rating its bitterness more pleasantly.
The key to the new process is ultrasound. These are sound waves above the range of human hearing. In our system, a small metal device called a transducer presses against the side of a traditional espresso basket and makes it vibrate rapidly. Those vibrations move through the water and coffee grounds. This creates a phenomenon known as acoustic cavitation. Tiny bubbles form and collapse in the liquid. When these bubbles collapse near coffee particles, they produce microscopic jets and forces that act a little like scrubbing brushes. They pit and fracture the surface of the coffee grounds, helping flavor compounds, oils and caffeine move into the water much faster than they normally would at room temperature. In other words, ultrasound helps us replace heat with mechanical energy.
[...] In earlier work, we used ultrasound to speed up cold brew dramatically. But the challenge in this project was different: could we produce something with the strength, body and intensity of espresso, without heating the water? To do that, we adjusted several variables. Brew ratio was one of the most important: how much water we used for each gram of coffee. Too much water and the drink becomes diluted; too little and extraction becomes difficult. Grind size also mattered. Finer grounds allowed us to extract flavor more rapidly. Finally, we tested how long the ultrasound should be applied. We found the sweet spot was about two-and-a-half to three minutes. Of course, making a concentrated coffee in the laboratory is one thing. The real test is whether people want to drink it. [...] For the espresso samples, participants could not reliably tell the traditional and ultrasonic versions apart. There were no significant differences in aroma, flavor, bitterness or overall liking. For filter coffee, the ultrasound version was actually preferred overall, with participants rating its bitterness more pleasantly.
Industrial scale (Score:5, Interesting)
Yes, this makes sense.
But for companies making ready-to-drink coffee products at industrial scale, it could be very significant indeed.
Coffee made at an industrial scale isn't expected to be *great* coffee, just "good enough". I can see the process being "good enough." For those who see coffee as just a base into which to stir their favorite (industrially produced) creamer, it will be just fine.
Coffee snobs will get to keep their heat-base process, they'll be the ones that care about fine nuances of flavor, and they don't drink the industrial stuff anyway.
So everybody's happy.
P.S.: Yes, I identify as a coffee snob.
Re: Industrial scale (Score:2)
As long as the daily fix of caffeine is there.
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For a factory making instant coffee granules, huge.
Not only will they save the energy from not having to boil water, they'll also save it when freeze-drying the room-temp output.
Of course, that won't make it any cheaper to actually buy...
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I also consider myself a coffee snob; bellman if I'm making a "nice" coffee, Aeropress in a pinch, and I'm low key stoked to try this, and gladly will buy into an appliance if it passes my personal taste test- I am fairly confident at this point that I'll be spending rest of my life mostly in places where most of the time, any heat and air moisture added to the household is a detriment (to be fair, probably, most of the planet going forward.), and so even if the power bill wasn't as eye watering as it's rig
Cut Coffee-Brewing Energy Use (Score:4, Insightful)
Anyone seen any data on the obvious hack version? (Score:2)
Gotta try putting a thin walled cup of what'd be a cold brew into a generic ultrasonic bath; surely that has do something.
Hands off my tea (Score:3)
... yes you are thinking about it . That water has to be just off the boil and the tea bag is Yorkshire, wars have been fought over less.
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Tea bags? What on earth! Sorry, you just lost the war.
Loose leaf, please and thank you.
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Not to mention the water has to be boiling, not just off the boil. What a barbarian!
Quirks (Score:2)
I had a colleague who was drawn into the hype. Of course I mentioned that I go for the cheapest coffee in the rack in the supermarket. I hunt for the cheapest. I rubbed it in.
Poor lad did not have time to go get his fresh coffee from the shop one day, so in desperation, he asked me if he could use one of my coffee pads. I thought about letting him sign a
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What's a coffee pad?
Mostly I drink kirkland signature filter these days (at work) and whatever's available locally in a cafetiere at home.
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I have read nothing but the title (Score:2)
And I already know the perfect song for the perfect blend [youtube.com] to blare into your morning espresso and summon the spirit of consciousness into your cold bleary-eyed body and broken soul.
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Pointless Exercise (Score:2)
Stop trying to fix something that isn't a problem. Energy usage while making coffee has never been significant in the grand scheme of things.
Forget it, Jake (Score:2)
it's Slashdot.
Comparable (Score:2)
No, I don't want comparable. I want the real deal.
Who wants room temperature expresso ??? (Score:2)
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Sell it as coldbrew espresso, make it look and feel high quality, get one high profile Michelin chef to use it.
Make the Pacojet of coffee. It will sell, but 1000$ is probably too cheap (not for manufacturing cost, but for market positioning).
With how much stainless steel particulates? (Score:2)
High intensity ultrasound isn't just good at blasting particles apart, but also the transducer.
The molecular cooking community has experimented with it, didn't like the metallic aftertaste.