Estimated reading time:8 minutes

Key takeaways

• Ultrasonic espresso uses high-frequency sound waves to extract espresso-strength coffee from room-temperature water.
• Blind taste tests found no difference between ultrasonic and traditional espresso.
• The brewing process takes three minutes, far slower than conventional espresso.
• Commercial ready-to-drink coffee manufacturing will benefit more than cafés.

Espresso is loved the world over. It’s the second-most-consumed drink in Italy, and consumption in markets like the US, which traditionally favour filter coffee, has reached record levels, according to the 2026 NCDT Specialty Coffee Report.

Yet every few years, espresso seems to get reinvented. The traditional method has real drawbacks. It requires high temperatures and high pressure, consumes a lot of energy, produces significant waste, and baristas often struggle with inconsistent extraction.

So researchers keep searching for “better” ways to pull a shot. Now we have “ultrasonic espresso” – but what is it exactly?

You may also likeour article revisiting extract chilling.

A classic reinvented

Espresso is a short, concentrated drink brewed under high pressure (around 9 bar) using finely ground coffee. It’s extracted at a 1:2 water-to-coffee ratio for 25 to 40 seconds, resulting in a rich, bold, and viscous beverage with a distinct reddish-brown crema.

Invented in the early 1900s, espresso has stood the test of time. But science wants to reinvent it.

In the early 2000s, Montreal’s coffee scene became synonymous with the allongé: a long shot of espresso extracted at a ratio between 1:4 and 1:6. The drink was developed in response to the growing popularity of lighter roast profiles and washed coffees. By grinding much coarser and extracting higher yields within the typical timeframe, it’s easier to pinpoint fruity flavours.

Two decades later, the Systematically Improving Espresso study introduced “turbo shots”, extracted in 10 to 18 seconds by grinding coarser, using smaller doses, and lowering pressure. The idea was to use less coffee, reduce waste, and improve extraction efficiency and consistency.

Renowned restaurant Noma also experimented with “Nomacanoes” in 2020 to improve workflow and maximise extraction efficiency. Co-developed with Noma’s then-roaster Tim Wendelboe, the drink sits somewhere between espresso and filter.

Most recently, pre-batched espresso has divided specialty coffee. The practice involves pulling shots in advance, chilling them, and serving them to order for milk drinks. Advocates like Project Zero claim it speeds up service and that customers can’t taste the difference. Opponents argue it diminishes the craft of espresso.

Each innovation promised to solve specific problems: speed, waste, consistency, flavour.

Now researchers at the University of New South Wales (UNSW) have added a new entrant to the list: “ultrasonic espresso”. Dr Francisco Trujillo and his team at UNSW’s School of Chemical Engineering have developed a process that uses high-frequency sound waves to pull espresso-strength coffee from room-temperature water.

How does “ultrasonic espresso” work?

Using ultrasonic sound waves for espresso isn’t a new idea. Dr Robert McKeon Aloe experimented with ultrasonic mixing after extraction, and he found it reduced sourness and bitterness while giving the coffee a silkier mouthfeel.

A similar technique applies ultra-low-frequency electromagnetic waves, at roughly 500 Hz, to espresso. Jack Simpson used it in his 2024 World Barista Championship routine, explaining that “post-extraction improvement” energises the water molecules so that polyphenols, including caffeine, bond together. The result is less perceived bitterness, along with greater sweetness and balance.

Extracting espresso with ultrasonic sound waves, however, is new. Dr Trujillo’s team pressed a transducer, a small metal device, against the side of the portafilter basket. It generates ultrasonic sound waves that cause the basket to vibrate rapidly during extraction.

The vibrations pass through both the coffee grounds and water, triggering a phenomenon called “acoustic cavitation”. Microscopic bubbles form and collapse at speed, acting like tiny scrubbing brushes against the ground coffee particles. This releases flavour compounds, oils, and caffeine into the water far faster than room-temperature water would allow.

“We call it an ultrasonic espresso. It’s a different process, but you get the same richness and concentration of a normal espresso in under three minutes,” says Dr Trujillo. “Traditionally, espresso is made by forcing hot water through coffee under pressure. But with ultrasound we can use room-temperature water instead, reducing energy consumption by up to 75%.”

Cold brew vs espresso

This isn’t Dr Trujillo’s first time reimagining classic coffee drinks. His team previously developed a patented cold brew system, compressing a process that traditionally took 12 to 24 hours into about three minutes. 

But extracting ultrasonic cold brew and espresso requires entirely different approaches. 

“The most important [factor] was the brew ratio… because this helps ensure the final drink is concentrated and not too diluted,” Dr Trujillo says. “Another important factor is how finely the coffee beans are ground. We found that by grinding finer we could extract the flavour more rapidly.

“We also experimented with how long the sound waves were applied, as this can affect both the concentration and flavour of the coffee. What we found is that between two-and-a-half and three minutes is a sweet spot for producing a balanced cup.”

So, what does “ultrasonic espresso” teach us?

“Ultrasonic espresso” is unlikely to find its way into coffee shops, but the sensory results are surprising.

UNSW ran a blind evaluation with around 100 regular coffee drinkers, rather than trained tasters. Participants were served four types of coffee: traditional espresso, ultrasound-brewed espresso, traditional filter coffee, and ultrasound-brewed filter coffee, all cooled to the same temperature and served in identical cups. Each drink was rated on aroma, flavour, bitterness, and overall liking.

The results were unambiguous for espresso. There was no significant difference between the traditional and ultrasonic versions across any measure, and no clear preference either way. 

Interestingly, participants preferred the ultrasound-brewed filter coffee overall, rating its bitterness as more pleasant than traditional filter coffee. “These findings showed that using ultrasound didn’t harm taste, and in some cases even improved it, despite brewing at room temperature and without the heat normally associated with coffee making,” says Dr Trujillo.

Ultimately, this suggests that temperature and pressure, two pillars of espresso extraction, aren’t strictly necessary to meet the same sensory targets, provided sufficient mechanical energy comes from elsewhere. 

For an industry that treats the 9-bar, 90-something-degree extraction as standard, “ultrasonic espresso” is worth contemplating – although taste tests from qualified coffee professionals are necessary.

Where the real commercial value lies

A conventional espresso shot is ready between 25 and 40 seconds, whereas “ultrasonic espresso” takes up to three minutes. In any café, whether during a morning rush or a slow afternoon, increasing extraction time sixfold isn’t feasible.

Dr Trujillo points to where the real opportunity lies. “There are companies that make coffee products on an industrial scale, and we are confident this ultrasound system can be scaled up to meet their needs, delivering real benefits in terms of reduced processing times and energy use,” he says. “The 75% energy saving is particularly beneficial at that scale, and we are also able to produce the coffee very quickly.” 

He adds that because the process yields a concentrated, espresso-strength coffee, it could be used directly in ready-to-drink manufacturing or used as a concentrate for cold brew and milk-based drinks.

High energy costs, water waste, and inconsistent extraction are real problems, and researchers should keep testing new ways to solve them. UNSW’s work adds a credible data point: sound waves can substitute for heat and pressure without sacrificing flavour, at least according to 100 blind tasters.

Not every solution to a coffee problem should make its way behind the counter of a café. Some belong in a lab, refined further, tested at scale, and eventually licensed to manufacturers who truly benefit.

Ultrasonic espresso is exactly this kind of innovation, so don’t expect to see it in your local coffee shop any time soon.

Need more leads for your coffee business? Get in touch with PDG Media, our marketing agency dedicated to specialty coffee,here.

Ultrasonic espresso FAQs

What is ultrasonic espresso?
It’s a brewing method developed by Dr Francisco Trujillo’s team at the University of New South Wales that uses high-frequency sound waves to extract espresso-strength coffee from room-temperature water in under three minutes.

Does ultrasonic espresso taste different to traditional espresso?
In a blind test with 100 regular coffee drinkers, participants showed no significant preference between traditional and ultrasonic espresso across aroma, flavour, bitterness, and overall liking.

Will ultrasonic espresso make its way to coffee shops?
It’s highly unlikely to be used in cafés. It takes up to three minutes per shot compared to 25 to 40 seconds for traditional espresso. Dr Trujillo sees more value in ready-to-drink coffee manufacturing.

Photo credits: University of New South Wales

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