One thing most coffee lovers agree on is that good espresso starts with hot water. A team of researchers in Australia is challenging that idea. Scientists at the University of New South Wales say they have developed an “ultrasonic espresso” system that can brew coffee at room temperature using high-frequency sound waves instead of heat. And according to early taste tests, people could barely tell the difference.
Meet the world’s first ‘sonic espresso’
The new system uses ultrasound, high-frequency sound waves that humans can’t hear, to extract flavor, aroma, oils, and caffeine from coffee grounds. Instead of heating water, the researchers rely on a process called acoustic cavitation.
The simple version is that tiny bubbles form in the water and rapidly collapse, creating microscopic currents that move liquid around the coffee grounds and pull out soluble compounds. In other words, the sound waves do the work that heat normally does.
The team built a specialized device that sends ultrasonic vibrations throughout the entire coffee filter, effectively turning it into what researchers describe as an acoustic reactor.
It takes longer but uses far less energy
Usually, espresso takes about 30 seconds to brew. But the ultrasonic version takes closer to three minutes. That’s slower, but there’s a tradeoff, as the system uses roughly 75% less energy than a conventional espresso machine.
Researchers say that could make a significant difference for coffee shops, restaurants, ready-to-drink coffee manufacturers, and industrial-scale beverage producers. With energy costs climbing, a machine that produces espresso-like coffee while using a fraction of the electricity could attract serious attention.
Will it actually taste like espresso?
The researchers adjusted variables like grind size, brewing time, and ultrasound power until they achieved extraction levels similar to what the Specialty Coffee Association considers ideal for espresso. Then they put the coffee to the ultimate test: people.
When a group of 100 participants sampled both conventional espresso and the ultrasonic version, most people showed no meaningful preference between the two.
Participants rated aroma, flavor, bitterness, and overall enjoyment almost identically. Even more surprising, when researchers compared traditionally brewed filter coffee with ultrasonically brewed filter coffee, participants generally preferred the ultrasonic version.
Coffee makers could look very different in the future
The researchers aren’t claiming they have replaced espresso machines entirely. The drinks are not chemically identical to traditional espresso. But the study, published in the Journal of Food Engineering, suggests that producing espresso-strength coffee without heating water is possible.
That opens the door to entirely new types of coffee machines capable of making espresso, filtered coffee, and cold brew all using the same underlying technology.
Source: WIRED