A team of scientists replaced an espresso machine’s heat with sound, and 100 tasters couldn’t pick the difference

Researchers at the University of New South Wales have found a way to brew espresso strength coffee without using heat at all. Led by Dr. Francisco Trujillo, the team developed a method that relies on ultrasonic waves instead of pressurized hot water to extract flavor from coffee grounds. The technique reportedly replicates the taste, aroma, and caffeine content of a traditional shot while cutting energy use by roughly 75 percent.

As detailed by Wired, the process works by turning a standard filter basket into an acoustic reactor. A small transducer is pressed against the side of the basket, generating high frequency sound waves that travel through the water and coffee grounds and trigger a phenomenon called acoustic cavitation.

The cavitation process creates tiny bubbles that rapidly form and collapse near the coffee particles, acting like microscopic scrubbing jets that fracture the grounds and release flavor compounds faster than heat alone would. Dr. Trujillo said ultrasound helps replace heat with mechanical energy.

Researchers fine tune the brewing variables for a balanced cup

The research, published in the Journal of Food Engineering, examined variables including brew ratio, grind size, and the duration of ultrasonic treatment. A finer grind extracted flavor more efficiently, and a brewing time of two and a half to three minutes produced the most balanced results. That window runs longer than a typical 30 second espresso pull, though the researchers say the energy savings offset the added time.

To test the method, the team ran a blind sensory evaluation with 100 regular coffee drinkers, similar to how viral taste tests on social media have recently put snack ingredients under scrutiny, including a chip coated in sea salt that drew its own reaction online. Participants were served four samples, traditional espresso, ultrasound brewed espresso, traditional filter coffee, and ultrasound brewed filter coffee, all in identical cups at matched temperatures. According to the university, the espresso comparison showed no notable preference between methods, and tasters could not tell the two apart.

The filter coffee results favored the ultrasound version, with participants noting the bitterness came across as more pleasant. Dr. Trujillo noted that when the ultrasonic espresso was given to 100 regular coffee drinkers in a randomized test, they could not tell it apart from a normal espresso.

The researchers see potential industrial applications, particularly for companies producing ready to drink coffee at scale, where the savings in both energy and time could be significant. The system produces a concentrated, espresso strength liquid that could be adapted for milk based drinks or cold brew, a process that conventionally takes 12 to 24 hours but Trujillo’s prior ultrasound research showed could be completed in three minutes.

The team believes the same approach could eventually be built into a consumer coffee maker, though no commercial device has been announced. Health related viral claims about routines and food, including a viral 36-hour fast video, have drawn similar scrutiny from experts in recent weeks.

The findings have been published in the Journal of Food Engineering, and the research team has not announced a timeline for bringing ultrasonic brewing equipment to market.