The University of New South Wales in Sydney has developed a technology for making espresso without hot water. Instead of heating, it uses ultrasound: high-frequency sound waves help extract aromatic compounds, oils and caffeine from ground coffee. A drink with the strength of classic espresso is produced in 2.5 to 3 minutes using room-temperature water.
According to the authors, the new method can reduce energy consumption by about 75%, since it eliminates the most energy-intensive stage — heating the water. The process is based on acoustic cavitation: ultrasound creates microscopic bubbles that collapse and speed up the extraction of flavor components from the coffee beans.
The technology was tested in a blind randomized study involving about 100 coffee lovers. They evaluated traditional and ultrasound espresso, as well as two versions of filter coffee. For espresso, no statistically significant differences were found in taste, aroma or overall impression. And the filter coffee made with ultrasound was even slightly more popular among participants.
The technology may find use primarily in industrial production of ready-to-drink coffee beverages and concentrates, where speed of preparation and lower energy costs are especially important.
