ResearchJournal of Food Engineering· Jun 1, 2026T1 · Peer-reviewed / standard
Francisco Trujillo's group at UNSW Sydney turned a portafilter basket into an ultrasonic sonoreactor, coupling high-intensity ultrasound directly into a loosely packed coffee bed while water percolates through it. Cavitation bubbles collapsing against the grounds pit and fracture particle surfaces, so espresso-strength concentrations are reached in 2-3 minutes without heat or 9 bar; the paper reports the ultrasonic brew used 24.3% of the energy of a conventional espresso machine (the university's press material rounds this to 'up to 75% less'). Brew ratio, grind size and sonication time were tuned, and beverages were characterised for colour, pH, caffeine and chlorogenic acids. In a blind test, 100 regular coffee drinkers could not distinguish the room-temperature ultrasonic shot from a conventional espresso, and an ultrasound-brewed filter coffee was preferred on bitterness. Caveats: a lab prototype with no consumer device; untrained consumer panel rather than descriptive analysis; the energy comparison depends on the reference machine's standby and heating losses.
Why it matters: Nothing to buy yet, but it is the clearest demonstration so far that heat and pressure are means, not ends: strength and flavour compounds can be pulled out of coffee at room temperature if you supply the mechanical energy another way, which reframes how we think about cold and low-temperature extraction.
Published Jun 1, 2026 · collected Sep 5, 2026