404 Media report on an Australian team that has created cold espresso and a cold-brew coffee that takes a mere three minutes (instead of 12-to-24 hours) to make, thanks to a boost from ultrasonic technology to create “acoustic cavitation,” or tiny bubbles that can burst through the cell-walls of plant material like ground-up coffee beans:
The researchers at the University of New South Wales Sydney claim that their ultrasonic extraction held up to a “sensory analysis” and blind taste tests by trained experts: “A sensory analysis was conducted to evaluate appearance, aroma, texture, flavor, and aftertaste, which demonstrated that coffee brewed for 1 and 3 min in the sonoreactor exhibited almost undistinguishable properties compared to a standard 24 hour [cold] brewing without ultrasound,” they write in a paper about the method in the journal Ultrasonics Sonochemistry.
—
You can read more of the cold-coffee techniques here, in Ultrasonics Sonochemistry.