Making espresso with ultrasound

darktoto 84 points 76 comments June 16, 2026
www.unsw.edu.au · View on Hacker News

Discussion Highlights (15 comments)

thomasoffinga

Someone get James Hoffmann on the line right now.

mzitelli

75% energy save to make a room temperature expresso. I am ok spending a bit more energy to have it warm.

alansaber

Not even the baristas are safe. Technology really is coming for everyone.

abujazar

The crema looks like terrible, more like Nespresso, and having the coffee warm is kinda important. But perhaps this can be used in the instant coffee industry or something.

uberex

Awesome idea. I would love to try it. If that can also make my espresso routine easier I am up for it.

fabian2k

But people want to drink coffee/espresso hot, not room-temperature. So you have to heat the water afterward anyway. I'm not seeing that much potential for energy savings here, unless you're comparing setups with large boilers inefficiently used for small amounts of coffee.

elAhmo

When you thought that coffee snobs couldn't get any worse...

erikgahner

What exactly is the innovation here compared to the press release from two years ago?[1] [1]: https://www.unsw.edu.au/newsroom/news/2024/05/Ultrasonic_col...

swiftcoder

Does this work with cold water? Because if so, my iced espresso drinks are crying out for it Where's James Hoffmann when you need him?

jurf

> Both espresso samples were served at 22 °C to ensure a fair like-for-like comparison […] > It is noted that espresso is normally consumed hot and has transient sensory attributes that are temperature- and time-dependent. Hence, serving espresso at 22 °C will alter its sensory characteristics. This is a weird test, coffee get’s so much worse when cold. So people can’t distinguish between two bad coffees.

supertroop

This sounds awful. I’m an espresso snob and caffeine isn’t even on my list of why I love it. It’s like they complete ignored what makes a good shot and focused on one element.

emptybits

Of all the objective and subjective metrics a home coffee drinker is trying to optimize, never once have I heard anyone care in the least about the watt-hours consumed during the brew process. "I really wish I could drink coffee at room temperature all the time and save a penny on electricity while doing it!" Someone will do the math, I'm sure it's not exactly a penny. TL;DR: Aiming for a high-volume industrial goal, tone-deaf to coffee enthusiasts.

cush

This is really cool, I have so many questions! What's interesting to me is they only replaced the hot water part of the equation, and the system still requires high pressure. How does ultrasound affect flow rate? Do fines sink to the bottom of the puck and choke the shot? There is a new movement happening, especially in lighter roast coffees, where we're finding that more balanced extractions (less bitterness/acidity/acridity) are happening at lower pressures, even going so far as grinding so coarse that the puck offers zero resistance - effectively making the pump the limiting factor for flow rate. Light roast coffee is much less porous and more hydrophobic. I wonder if adding ultrasound would allow light roasts to yield more extraction in general, maybe even keeping the high temperature. Or, would adding ultrasound allow a finer grind size and more resistance without adding the harsh flavors of a high-temperature shot. So many experiments to be done!

Febriss33

mmm.. what about pressure? the real espresso need pressure... is not just hot water. is the pressure of the expanding water that pushes it... not sure it would be the same stuff lol

cocodill

It immediately brings to mind that YouTube video where a guy was making whiskey out of vodka and oak chips in an ultrasonic bath.

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