Researchers at the University of New South Wales have developed a method to produce espresso-strength coffee using ultrasonic sound waves and room-temperature water. The process cuts energy use by up to 75 percent compared with traditional machines. Blind taste tests showed no significant difference from conventional espresso.
Dr Francisco Trujillo and his team at UNSW’s School of Chemical Engineering pressed a transducer against the portafilter basket to generate high-frequency sound waves. These waves create acoustic cavitation that releases flavor compounds and caffeine from the grounds.
The method takes up to three minutes per extraction, far longer than the 25 to 40 seconds required by standard espresso machines. Dr Trujillo said the approach yields the same richness and concentration as a normal espresso.
A blind evaluation with about 100 regular coffee drinkers found participants rated ultrasonic and traditional espresso equally on aroma, flavor, bitterness, and overall liking. The team sees greater potential for industrial-scale ready-to-drink coffee production than for café use.
Dr Trujillo noted that the system could be scaled to reduce processing times and energy consumption in manufacturing. He added that the concentrated output could serve directly in ready-to-drink products or as a base for other drinks.
