A New Way to Make Espresso
For decades, making espresso has relied on two essentials: hot water and pressure. Now, researchers at the University of New South Wales (UNSW) in Australia have demonstrated that one of those ingredients may no longer be necessary. Their new brewing technique uses ultrasonic sound waves to create espresso-strength coffee at room temperature while consuming around 75% less energy than conventional espresso machines.
The breakthrough, published in the Journal of Food Engineering, could pave the way for more sustainable coffee production without sacrificing taste.
How Sound Waves Replace Heat
Instead of heating water to nearly boiling temperatures, the researchers use high-frequency ultrasound to extract flavors, oils, aromas, and caffeine from coffee grounds. The process relies on a phenomenon known as acoustic cavitation. Tiny bubbles form and rapidly collapse in the water, generating microscopic forces that break down coffee particles and accelerate extraction.
As a result, the system can produce espresso-strength coffee in just two to three minutes using room-temperature water. Researchers optimized factors such as grind size, brewing time, and ultrasound intensity to achieve results comparable to traditional espresso.
Taste Test Delivers Surprising Results
To determine whether consumers could notice a difference, the team conducted blind taste tests involving 100 regular coffee drinkers. Participants compared conventionally brewed espresso with the ultrasonic version without knowing which was which.
The results showed no significant differences in flavor, aroma, body, or overall enjoyment. Most participants could not distinguish between the two drinks, and neither method emerged as the clear favorite. In separate tests, participants even preferred the ultrasound-brewed filter coffee over a standard pour-over brew.
Potential Benefits Beyond the Coffee Shop
Although the technology remains in the research stage, its greatest impact may come in large-scale coffee manufacturing. By eliminating the need to heat water, producers could significantly reduce energy consumption while shortening processing times.
If commercialized, ultrasonic brewing could offer a greener and more efficient way to prepare coffee, proving that great espresso does not necessarily require heat.
