Scientists Develop Method to Make Espresso with High Pressure Waves—No Hot Water Required

What do you want to do well espresso? Ground coffee, of course; machine able to make a run; and hot water, preferably heated to between 195 and 205 degrees Fahrenheit. And that’s it. But can a person be without the last thing? No, not just water, but the need to heat it.

A Colombian scientist, Francisco Trujillo, led a team at the University of New South Wales in Australia, which claims to have invented what it calls “ultrasonic espresso.” As Trujillo explained, “it’s a home brewing process that uses high-energy waves to remove flavor, oil, aroma, and caffeine from brewed coffee.”

Although the process takes longer than the conventional method (three minutes compared to 30 seconds), it uses 75 percent less energy – a great benefit for coffee shops and restaurants, but especially for businesses that produce large amounts of coffee in factories, such as those that produce ready-to-drink products.

Sonic Brew

The test system direct waves directly in the filter contained the ground beans in the water. Instead of relying on heat, the technology uses a phenomenon called acoustic cavitation. This involves the creation and collapse of particles that produce microcurrents that, in this experiment, help remove soluble compounds from coffee.

To create these microcurrents, scientists have created a device that can send strong vibrations throughout the filter basket, turning it into a buzzer. This design allows the waves to hit multiple points at once and accelerate the movement of the liquid around the coffee particles. “Ultrasound helps us in hot places with mechanical energy,” explains Trujillo.

The purpose of this entire process, detailed in this month of the Journal of Food Engineering, and achieve the same concentration as espresso. To do this, the researchers changed various factors such as the size of the digester, the intensity of the ultrasound, and the incubation time. Using a fine grinder and 100 watts of power, they achieved brews with levels of soluble solids and yields similar to what the Specialty Coffee Association considers good.

When the experiments were repeated under the same conditions but without ultrasound, it was not possible to achieve these results. The ultrasonic system made it possible to make coffee with the same strength as espresso in just a few minutes-researchers found the right time to be between two and a half and three minutes-using water to heat.

The group also analyzed different levels of medicine. The concentrations of caffeine and chlorogenic acid were similar to those obtained by conventional methods. No significant difference was observed in pH or in the total concentration of volatile compounds responsible for the odor.

Taste Test

A group of 100 people participated in cognitive tests that compared brewed espresso with regular espresso. In the end, participants did not show a preference for either strategy. Ratings of smell, taste, bitterness, and overall acceptance were similar.

He also compared the filtered coffee prepared using the treatment method with ultrasound. “In terms of filtered coffee, the ultrasonically produced version was preferred, and the participants rated its bitterness as pleasant,” Trujillo said.

In addition to mimicking the characteristics of espresso coffee, this new method can also help the environment. The measurements obtained by the researchers show that, in order to produce drinks of the same strength, the electric machine uses only 24 percent of the energy used by the espresso machine.

The authors emphasize that coffee produced using ultrasound is not the same as traditional espresso. However, the results show that it is possible to make drinks with the same chemical and sensory properties without heating water.

This research opens up the possibility of developing new coffee makers that can prepare everything from espresso to filtered coffee and cold brew using the same technology. If this machine is brought to the market, the sound of the espresso machine may be replaced by an inaudible ultrasound vibration.

This article was originally published by WIRED in Spanish and translated from Spanish.