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- Hacker News
- > For filter coffee, however, the ultrasound-brewed version performed even better: participants significantly preferred it overall, particularly rating its bitterness as more pleasant.
I'm surprised by this, my assumption from hot coffee vs cold brew was that since the water isn't hot, there wouldn't be as much bitterness? Or maybe I'm reading it wrong and it's why they prefer it, because it's less bitter?
by m-p-3 - It immediately brings to mind that YouTube video where a guy was making whiskey out of vodka and oak chips in an ultrasonic bath.by cocodill
- 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.by supertroop
- 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...
by erikgahner - 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?
by swiftcoder - Wonder why they chose to stick with the portafilter form factor rather than something custom for the method. Perhaps it just fits the task well and they don't need to change, or they want to preserve the look of an espresso machine. Though, if the water is room temp, they only really need the pressure, which doesn't need the entire machine. Seems pretty cool.
Edit: The article shows that they chose this method specifically to use the basket, and the basket allows for the vibrations they need. The other conveniences of the basket form factor also come into play; reloading, cleaning, etc. and don't need reinventing or retraining. Cool stuff. I wonder whether they'll remodel the machine around the basket and remove what's not needed if this becomes a product.
by nusl - 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!
by cush - > 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.
by jurf