Scientists have now demonstrated that espresso-strength coffee can be brewed using low-temperature water and ultrasonic sound waves. It sounds like science fiction - but it could have real implications for espresso, cold brew and the future of coffee.

What if the future of espresso does not begin with hotter water - but with sound?

Researchers in Australia have demonstrated a new way of producing espresso-strength coffee using ultrasonic sound waves and low-temperature water.

Yes. Sound.

Instead of relying mainly on heat to speed up coffee extraction, the experimental system uses high-frequency ultrasound to help release flavour, aroma, oils, caffeine and soluble compounds from ground coffee.

The result is what researchers are calling ultrasonic espresso - a concentrated coffee brewed in around two to three minutes at low temperature.

And the potential implications for espresso brewing, cold brew coffee, cafe equipment, ready-to-drink coffee and energy-efficient coffee production are fascinating.

What Is Ultrasonic Espresso?

Ultrasonic espresso is a new coffee extraction technique that uses high-frequency sound waves to increase the movement of soluble compounds from coffee grounds into water.

Traditional espresso normally uses water at approximately 90-95°C, together with pressure of around 9 bar, to rapidly extract a concentrated coffee.

Ultrasonic coffee brewing approaches extraction differently.

Researchers developed a system that sends ultrasound directly through the coffee basket while water moves through the ground coffee.

The process creates an effect known as acoustic cavitation.

Ultrasound causes microscopic bubbles to rapidly form and collapse in the water. When those bubbles collapse close to particles of ground coffee, they create tiny but powerful forces that disturb and fracture the surface of the coffee.

This increases mass transfer and helps water extract soluble compounds from the coffee much faster than room-temperature water normally could.

Can You Really Make Espresso Without Hot Water?

This is where things get interesting.

Under normal brewing conditions, using cool water to produce a strong espresso-style extraction would take far too long. That is one reason traditional cold brew coffee usually requires many hours of contact between coffee and water.

But ultrasound dramatically accelerates coffee extraction.

In a 2026 study published in the Journal of Food Engineering, researchers were able to produce espresso-strength coffee in approximately two to three minutes at low temperature.

By adjusting coffee grind size, coffee-to-water brew ratio, ultrasonic power and extraction time, the researchers achieved levels of Total Dissolved Solids (TDS) and Extraction Yield (EY) associated with traditional espresso.

At the finest grind tested, the ultrasonic coffee also reached the commonly referenced ideal coffee extraction-yield range of 18-22%.

When the same low-temperature process was attempted without ultrasound, it could not achieve the same espresso-strength extraction.

What Does Ultrasonic Espresso Taste Like?

Of course, clever technology means very little if the coffee does not taste good.

Researchers tested the ultrasonic espresso against traditionally brewed espresso with 100 regular coffee drinkers.

To make the comparison fair, both coffees were evaluated at approximately the same temperature.

The researchers found no statistically significant difference in consumer preference between the ultrasonic espresso and conventional espresso across the main liking measures tested.

The study also compared characteristics including colour, pH, caffeine and chlorogenic acid concentration and found no statistically significant differences in those key markers under the conditions tested.

That does not mean a low-temperature ultrasonic espresso will taste exactly like your favourite freshly pulled hot espresso when served over the counter. Serving temperature itself has an enormous effect on the way we perceive aroma, sweetness, acidity, bitterness and mouthfeel.

But it does suggest something remarkable: heat may not be essential for producing espresso-strength coffee extraction.

Could Ultrasonic Coffee Use Less Energy?

Potentially, yes - and this may prove to be one of the most important parts of the research.

Espresso machines require considerable energy because water, boilers, group heads and other metal components must be heated and maintained at brewing temperature.

In the researchers defined test, the ultrasonic system consumed only 24.3% of the operational energy required by the conventional espresso machine to produce three drinks of comparable strength.

In other words, the experimental ultrasonic system used approximately 75% less operational energy under those test conditions.

For one coffee at home, that may not sound revolutionary. Across thousands of cafes, coffee factories, bottled cold brew lines, offices and homes, energy-efficient coffee extraction technology becomes very interesting.

The Story Actually Started With Ultrasonic Cold Brew

The idea did not suddenly appear with espresso.

Australian researchers had already demonstrated that ultrasound could dramatically reduce the time required to make cold brew coffee.

Traditional cold brew commonly takes around 12 to 24 hours.

Researchers developed an ultrasonic system capable of producing cold brew-style coffee in less than three minutes. Instead of waiting for slow diffusion to extract the coffee over many hours, ultrasound dramatically accelerated the movement of flavour compounds, oils and aroma from the ground coffee into the water.

Why Ultrasonic Cold Brew Could Be Huge

At Kimberley Coffee Company, this is the area we find particularly interesting.

Cold brew coffee is already one of the fastest-growing ways of enjoying coffee, particularly in warm climates.

But traditional cold brew has practical limitations: long brewing times, containers, refrigeration space, production planning, filtration and the need for consistent extraction.

Imagine instead being able to produce a fresh cold brew coffee on demand in several minutes.

That could change the economics of cold brew for cafes, restaurants and commercial coffee companies. For bottled drinks and ready-to-drink coffee, the possibilities could be even bigger.

Does This Mean Espresso Machines Are Finished?

Definitely not.

Your local cafe is not likely to throw its espresso machine out next week.

Speed is still a major issue. A good commercial espresso machine can produce an espresso shot in roughly 25-35 seconds. The current ultrasonic espresso process takes around two to three minutes.

During the morning rush, that is a big difference.

There is also much more to cafe espresso than extraction numbers alone. Baristas care about crema, aroma, mouthfeel, temperature, consistency, speed, workflow, milk integration and equipment reliability.

Commercial espresso machines have had more than a century of development. Ultrasonic espresso is still emerging technology.

Could Ultrasound Change the Future of Coffee?

Possibly.

The exciting part is not necessarily whether ultrasound replaces espresso machines. It is that researchers have demonstrated another way of extracting coffee.

For decades, most coffee brewing conversations have revolved around the same basic variables: coffee, water, grind, temperature, pressure and time.

We may now have another variable to add: sound.

Future ultrasonic coffee technology could potentially influence espresso brewing, rapid cold brew, coffee concentrates, ready-to-drink coffee, commercial extraction, portable coffee equipment, low-energy coffee machines and automated brewing systems.

Research will determine which of those applications actually make commercial sense. But this is certainly technology worth watching.

What Does This Mean for Specialty Coffee?

Great brewing equipment can help you extract coffee. It cannot create flavour that was not in the beans in the first place.

Whether your coffee is brewed using a traditional espresso machine, pour-over, cold brew system or one day an ultrasonic coffee machine, the fundamentals remain exactly where they have always been: start with great coffee.

Bean quality, roasting, freshness, grind size, water and extraction all matter.

At Kimberley Coffee Company, we have been roasting specialty coffee in Broome, Western Australia since 2008.

We are fascinated by the science behind coffee because understanding extraction ultimately helps us produce a better cup.

Ultrasonic espresso may sound like science fiction. It is not. The technology is already working in the laboratory.

Whether we will eventually hear the hum of ultrasound alongside the familiar hiss of steam wands in cafes remains to be seen.

But one thing is certain: coffee is still evolving. And that is one of the reasons we love it.

Frequently Asked Questions About Ultrasonic Coffee

What is ultrasonic coffee?

Ultrasonic coffee is coffee extracted using high-frequency sound waves to accelerate the transfer of soluble compounds, oils and flavours from ground coffee into water.

What is ultrasonic espresso?

Ultrasonic espresso is espresso-strength coffee produced using ultrasound-assisted extraction rather than relying primarily on high-temperature water.

Can espresso be made with room-temperature water?

Research published in 2026 demonstrated that ultrasound-assisted brewing could create espresso-strength coffee at low temperature in approximately two to three minutes.

How does ultrasound extract coffee?

Ultrasound creates acoustic cavitation, where microscopic bubbles rapidly form and collapse. This action disrupts coffee particles and improves the movement of soluble coffee compounds into water.

Does ultrasonic espresso contain caffeine?

Yes. Researchers found no statistically significant difference in caffeine concentration between the ultrasonic and conventional espresso samples under the tested conditions.

Does ultrasonic coffee taste like espresso?

In a consumer study involving 100 regular coffee drinkers, researchers found no statistically significant preference difference between conventional espresso and ultrasonic espresso when both were evaluated at the same temperature.

Is ultrasonic coffee more energy efficient?

In the experimental operating scenario studied, the ultrasonic brewing system consumed about 24.3% of the operational energy of the conventional espresso machine - approximately a 75% reduction.

Can ultrasound make cold brew faster?

Yes. Earlier Australian research demonstrated ultrasonic cold brew production in less than three minutes compared with traditional cold brew methods that commonly take 12-24 hours.