Using Sound Waves To Make Espresso Could Cut Coffee-Brewing Energy Use By 75% (theconversation.com) 74
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.
Re: (Score:3)
You definitely do not qualify as a coffee snob! :-)
Re: (Score:2)
Re:Industrial scale (Score:5, Insightful)
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...
Re: (Score:2)
Could also be interesting for cold brew iced coffee.
Re: (Score:2)
Or coffee ice-cream.
Re:Industrial scale (Score:5, Insightful)
The real savings though are going to come for the manufacturers of those pre-bottled coffee drinks you find in the chillers at supermarkets; that's the kind of scale TFS is alluding to; where the coffee is brewed in industrial sized vats. Especially so if the concentrate approach is viable; add one 10L (or whatever) carton to your vat, then dilute with whatever milk/fake-milk/water/flavouring combinations needed to assemble your pre-bottled coffee-based drink. Coffee snobs are not admitting to buying those either. Also, as a side-benefit, there will be less waste as the grounds will be processed centrally so can be collected and fed into a suitable secondary product - they're excellent for providing fertiliser for some plants, for instance.
All of which probably saves you enough power and money (globally) to run a single AI data centre for a few minutes, but such is the price of progress I guess.
Re: (Score:2)
I brew mine at room temperature for iced americanos. I like it because it is less bitter, but it takes more water (and pressure and time) to get a good extraction.
Re: (Score:2)
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
Re: (Score:2)
I'm an Aeropress guy myself, I might have to try your Bellman!
I can definitely see your curiosity, perhaps there's something about the process that produces better coffee than heat-brewing methods. But I'm skeptical of anything done at an industrial scale.
Re: (Score:2)
I did french press for a while and then switched to pour over because it requires less cleaning.
Re:Industrial scale (Score:4, Insightful)
Re: (Score:3)
Yes, there are coffee snobs like that. But it's not a requirement. Many of us swear by AeroPress coffee, made with a device that costs $35. https://www.amazon.com/AeroPre... [amazon.com]
As for this particular process, coffee snobs won't go for the *industrial scale* version, thought they *might* go for a personal-sized machine that does it.
The technology in this case seems pretty straightforward, there's no need for it to be expensive, in terms of the complexity of making the machine.
Re: (Score:3)
With the right hype, and a high enough price tag on the machine, the coffee snobs will be all over this.
Unless they have dogs -- "... ultrasound. These are sound waves above the range of human hearing."
Re: (Score:2)
Well, cold coffee drinks are popular these days. An espresso that is made at room temperature means you can make a cold espresso drink much quicker and with less energy since you don't have to boil water only to cool it back down again.
This would be something you'll find at Starbucks, fine purveyors of sugary coffee drinks. Honestly, they aren't far removed from soft drinks nowadays given the amount of su
Re: Industrial scale (Score:2)
The first example of this that comes to mind is the infamous Monster Cable versus metal coat hanger testing back in the early 2000's.
I can't say this "ultrasonic voodoo is good enough for the plebs" thing you're pushing is actually valid, and neither do you.
Re: (Score:2)
Yes, every form of snobbery has its pretenders, and Monster Cables are a good example. The pretenders don't do it for the love of the thing they are snobbish about, but to impress others. I'd argue such people aren't true snobs, but merely show-offs.
As the very title of my thread pointed out, my main issue is with *industrial scale.*
Who knows, maybe the process would make great coffee at a small scale! I personally doubt it, because I think heat does some things to the coffee that ultrasound will not. But I
Re: Industrial scale (Score:2)
Re: (Score:2)
For sure! Just like the blind test done, comparing sound quality between Monster cables and coat hangers! https://gizmodo.com/audiophile... [gizmodo.com]
Re: Industrial scale (Score:2)
Re: (Score:2)
There is a place for freeze dried industrial coffee products.
I keep Tasters Choice crystals in my camping gear and in my emergency survival pack. I also have a LifeStraw, a bottle, a metal cup and firestarting supplies. I can turn a puddle into clean water and either mix in coffee crystals and drink it, or make fire and have hot coffee... a luxury in a bad situation.
On a daily basis I prefer to take my time and make coffee in a french press, or espresso for a treat.
Re: (Score:2)
Yes, I agree freeze-dried coffee is great for camping. But while camping, exceptional taste is not a priority!
If you like your French press, you might want to try AeroPress. https://www.amazon.com/AeroPre... [amazon.com] It's a similar concept and inexpensive, but you don't get as much of the bitterness and "muddiness" that you get with the French press. It allows you to get a richer, stronger flavor, without the unwanted parts of the flavor profile.
Re: (Score:3)
AeroPress is awesome. I have used one at a friends place. My french press is big enough to make 2 full mugs of coffee, which fits my morning routine.
Re:Industrial scale [percolation?] (Score:2)
A coffee snob? Just the human to ask in lieu of an AI (which will just tell me whatever it thinks I want to here).
I've been wondering whatever happened to percolated coffee. I'm guessing it tastes bad, but I didn't start drinking coffee until decades after I last saw a percolator.
Re: (Score:2)
Yep, I've had percolator coffee. Because it steeps so long, the process extracts a lot of unwanted flavors from the grounds into the water, giving it a "muddy" flavor. The percolator was from an era when there was just...coffee, and the stuff diners served was good enough.
Re: Industrial scale [percolation?] (Score:2)
Re: Industrial scale [percolation?] (Score:2)
Re: (Score:2)
Perhaps there are coffee snobs who actually like that muddy flavor.
Re: (Score:2)
No, they aren't. A percolator cycles water through the grounds continuously. A moka pot forces water through the grounds once.
Cut Coffee-Brewing Energy Use (Score:4, Insightful)
Re:Cut Coffee-Brewing Energy Use (Score:4, Insightful)
Don't you see, AI is inventing ways for humans to consume less energy so it can eat it all.
Anyone seen any data on the obvious hack version? (Score:3)
Gotta try putting a thin walled cup of what'd be a cold brew into a generic ultrasonic bath; surely that has do something.
Re: Anyone seen any data on the obvious hack versi (Score:2)
Thinking the same thing. Maybe putting it in a tea bag?
Re: (Score:2)
Re: (Score:2)
I just now finished a glass if iced coffee prepared in the ultrasonic cleaner I use for cleaning bicycle parts. It seemed a little weak, however I have a couple of variables to tweak for further experimentation. On the plus side, iced coffee prepared at room temperature only needs a single ice cube, so there is much less dilution.
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.
Re: (Score:3)
Tea bags? What on earth! Sorry, you just lost the war.
Loose leaf, please and thank you.
Re:Hands off my tea (Score:4, Funny)
Not to mention the water has to be boiling, not just off the boil. What a barbarian!
Re: (Score:2)
Re: (Score:2)
Yes a great prop, just not ... British old boy. 8-)
Quirks (Score:3)
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 waiver first. Sometimes I suspect that they put asbestos in the cheap pads (quirk number 2, bored easily compensates with weird humor). You guessed it. He now uses ordinary coffee pads daily.
If this triggers you, no worries, we all are entitled to a few quirks. Stay proud of your perfect espresso. I may roll my eyes. People...
Re: (Score:2)
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.
Re: (Score:3)
Re: (Score:2)
What is this devilry?
Never seen one before! Is that basically a filter coffee thing with the filter around all sides for convenience?
My main filter (it's the one at work) is one of these:
https://www.nisbets.co.uk/novo... [nisbets.co.uk]
It takes a rather large paper filter. Less convenient for one cup, but it'll crank out 12, and keep them warm while cranking out 12 more.
Re: Quirks (Score:2)
Re: (Score:2)
Ah i see, so an alternative to those coffee pod machines? Less plasticky.
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.
Re: (Score:1)
Pointless Exercise (Score:3, Interesting)
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.
Re: (Score:3)
it's Slashdot.
User name checks out, plus that’s correct. This is a purchased ad to raise investment for a 3m dollar ultrasonic emitter array to replace a 5k dollar chunk of high resistance conductor. It’s also the reason why it’s unlikely to make it to coffee shops or homes until the emitters become fantastically cheap. It’s also why ultrasonic cleaners (this is a glorified one) are so damn expensive.
Re: (Score:2)
The heat and especially pressure make good espresso makers big and expensive. Ultrasonic emitters are cheap, small and plentiful.
Comparable (Score:2)
No, I don't want comparable. I want the real deal.
Who wants room temperature expresso ??? (Score:2)
Re: (Score:3)
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).
roasting the beans takes 99% of the energy (Score:1)
Making the coffee doesn't require that much energy.
You might as well use an hydraulic press to extract the oils and other goodies.
Re: (Score:2)
It's been done [youtu.be]. Quite messy.
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.
Sonicator (Score:2)
Any other chemists out there like me trying to figure out how to do this in their sonicator?
next (Score:2)
Cold brew (Score:2)
Re: (Score:2)
They were all slain by reading the news about an ultrasonic cold brew espresso. That's rough, being killed by the news AND STILL finding no relief.
Very significant indeed? (Score:3)
What percentage of coffee-brewing costs are from energy consumption? I would guess that most of the cost is the coffee itself.
To boil 500 mL of water that starts out at room temperature takes about 0.05 kWh, which costs very much less than one cent in pretty much any jurisdiction. Enough coffee to make two cups of coffee probably costs 5 to 25 cents. So I don't see the energy saving as being "very significant".
tea (Score:2)
Brewing tea will cut coffee brewing cost 100%.
Midjourney (Score:2)
So I could go get my whole body ultrasonic-ct scan done while holding a cup of ingredients and walk out of there with an espresso?
Decaf, anyone? (Score:2)
Bueller? Bueller?
Except... (Score:2)
1. I want my coffee hot.
2. There's no discussion of frothing the milk for my cappuccino.
I'll stick to my manual DeLonghi espresso maker.