Preparing a classic espresso is traditionally associated with the passage of boiling water under high pressure through finely ground coffee – a process that takes about 30 seconds and requires a significant expenditure of heat energy
Researchers have created a new method for extracting coffee that uses high-frequency sound waves instead of hot water. The result is a drink with the richness and strength of traditional espresso, prepared in less than three minutes, but with up to 75% lower energy consumption. The innovation promises serious optimizations for the industrial production of ready-made coffee drinks.
Preparing a classic espresso is traditionally associated with the passage of boiling water under high pressure through finely ground coffee – a process that takes about 30 seconds and requires a significant expenditure of heat energy. However, a new scientific project proves that hot water may not be a prerequisite for obtaining a high-quality and strong drink.
A team of scientists has developed technology for the so-called “ultrasonic espresso.” This is a room-temperature extraction process that relies on mechanical energy delivered through sound waves.
How does ultrasound replace heat?
The new method is based on a physical phenomenon known as acoustic cavitation. A small metal device (transformer) is attached to the portafilter of a standard espresso machine, which transmits rapid vibrations to the water and ground coffee.
These high-frequency waves, which are beyond the range of human hearing, create microscopic bubbles in the liquid. When they burst near the coffee particles, microscopic jets and forces are generated that break the surface of the beans. In this way, the aromas, oils and caffeine are transferred to the water much faster than would be possible at normal room temperature.
The process is significantly different from the familiar cold brew, in which the coffee is steeped in cold water for between 12 and 24 hours and has a much milder and more diluted taste. In ultrasonic espresso, scientists have achieved an optimal balance by precisely adjusting:
• The ratio of water to coffee (to avoid dilution);
• The grind size (a finer grind speeds up extraction);
• The exposure time, with the best results being achieved between two and a half and three minutes.
Industrial potential and energy savings
Saving up to 75% of energy by avoiding heating the water is a small advantage for home users or small cafes, but it has enormous significance on an industrial scale.
Companies that produce ready-to-drink bottled coffees, milk drinks or cold coffee products could use this concentrated extract directly. This would reduce not only electricity costs, but also processing and transportation times.
The consumer test: Is there a difference in taste?
To test the practical qualities of the development, the researchers conducted a blind test with about 100 regular coffee drinkers (non-professional tasters). The participants were offered four drinks in identical cups, cooled to the same temperature: traditional espresso, ultrasonic espresso, traditional filter coffee and ultrasonic filter coffee.
The results show that for espresso, consumers did not detect a significant difference between the standard and ultrasonic versions in terms of aroma, taste, bitterness or overall sensation. For filter coffee, the version prepared with sound waves was even preferred by the majority, with its bitterness being rated as more pleasant.
The experiment proves that by replacing thermal energy with mechanical energy, modern technologies can recreate the density and intensity of classic coffee in a far more economical way.
Source: sciencealert
Illustrative photo: pexels-onehundredseventyfive-12039010
