A traditional espresso is made by forcing boiling water through finely ground coffee under high pressure, a process taking roughly 30 seconds and requiring substantial heat energy. Researchers have developed a novel method using high-frequency sound waves to make coffee, resulting in a beverage with the richness of standard espresso, prepared in under three minutes, and using up to 75% less energy. This innovation could significantly optimize industrial coffee drink production.
Traditionally, espresso involves boiling water and high pressure with finely ground coffee, taking about 30 seconds and consuming a large amount of heat energy. A new scientific project demonstrates that hot water isn’t necessary for a quality strong drink. Scientists have devised a technology called “ultrasonic espresso,” a room-temperature extraction process using sound waves for mechanical energy.
Ultrasound replaces heat through a process called acoustic cavitation. A small metal device attaches to a standard espresso machine’s portafilter, transmitting rapid vibrations to water and ground coffee. These high-frequency waves, inaudible to humans, create microscopic bubbles that, when they burst near coffee particles, generate microscopic jets and forces breaking the bean surfaces. This transfers aromas, oils, and caffeine to water faster than at room temperature.
This differs significantly from cold brew, where coffee is steeped in cold water for 12 to 24 hours, resulting in a milder taste. Ultrasonic espresso achieves an optimal balance by adjusting:
- The water-to-coffee ratio (to prevent dilution);
- The grind size (finer grind accelerates extraction);
- The exposure time, achieving best results between two and a half and three minutes.
Industrial potential and energy savings are considerable, with up to 75% energy savings avoiding water heating. This is modest for home users or small cafes, but significant industrially. Companies producing ready-to-drink coffees could use this concentrated extract, reducing electricity costs and processing and transport times.
In a consumer test, researchers conducted a blind test with about 100 regular coffee drinkers, offering four drinks in identical cups at the same temperature: traditional espresso, ultrasonic espresso, traditional filter coffee, and ultrasonic filter coffee. Results showed no notable difference in aroma, taste, bitterness, or overall sensation between standard and ultrasonic espressos. For filter coffee, the sound wave version was preferred by most for its more pleasant bitterness.
The experiment illustrates that replacing thermal with mechanical energy allows modern technologies to replicate classic coffee’s density and intensity more economically.
Source: sciencealert
Illustrative photo: pexels-onehundredseventyfive-12039010
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