Researchers at UNSW Sydney say they have brewed espresso-strength coffee using room-temperature water and ultrasonic sound waves in just 2–3 minutes, claiming energy savings of up to 75% compared with conventional hot-water extraction. The work, announced on 1 June 2026 in a UNSW news release and published in the Journal of Food Engineering, positions ultrasound as a new low-energy brewing platform for both espresso-style and cold brew coffee.
According to UNSW news, the team used a patented ultrasonic brewing “sonoreactor” attached to a standard espresso-style filter basket to generate what they describe as an “ultrasonic espresso” in two to three minutes at room temperature. Trade title FoodManufacture reports that under identical conditions without ultrasound, espresso-strength extraction was not possible, highlighting the role of the sound waves rather than pressure or temperature alone.
Lead researcher Dr Francisco Trujillo, a senior lecturer in the School of Chemical Engineering at UNSW Sydney, told UNSW news: “We call it an ultrasonic espresso. It’s a different process, but you get the same richness and concentration of a normal espresso in under three minutes.” In the same release he contrasted the method with traditional espresso, which forces hot water through a coffee bed under pressure, saying that with ultrasound the team can instead use room-temperature water and reduce energy consumption by up to 75%.
The extraction relies on acoustic cavitation inside the coffee bed. As described by UNSW news, the ultrasonic waves create tiny bubbles in the liquid that collapse near coffee particles and behave like microscopic scrubbing brushes, pitting and fracturing the grounds to intensify extraction. FoodManufacture notes that the researchers identified between two-and-a-half and three minutes as a “sweet spot” for producing a balanced cup using this approach.
Taste has been a central test of whether the technology genuinely matches espresso rather than simply achieving higher strength. In blind experiments reported by UNSW news, participants could not reliably distinguish the ultrasonic room-temperature espresso from shots brewed in the traditional way. A summary by Dr Trujillo in The Conversation states there were no significant differences in aroma, flavour, bitterness or overall liking, and that using ultrasound did not harm taste and in some cases even improved it.
The espresso work builds directly on earlier ultrasound-based cold brew research at UNSW. In a 2024 article, UNSW news reported that ultrasonication reduced cold brew times from the typical 12–24 hours to less than three minutes by connecting a bolt-clamped transducer to the brewing basket via a metallic horn, effectively turning a standard espresso filter basket into an ultrasonic reactor operating at 38.8 kHz. In that study, further detailed in Ultrasonics Sonochemistry, sonication at 100 W doubled extraction yield and caffeine concentration compared with unsonicated samples and increased measured fatty acids eightfold under specific brewing conditions.
The research group also argues that ultrasound can form a unified platform for multiple coffee formats. FoodManufacture reports that the same ultrasonic system used for espresso-strength coffee can be configured to produce concentrated and filter-style coffees, and to cut cold brew production from hours to minutes. In The Conversation, Dr Trujillo writes that saving up to 75% of energy by not heating water is a minor benefit for home users or small cafés, but that for companies making ready-to-drink coffee products at industrial scale it could be “very significant indeed”.
Industrial applicability has been a recurring theme in the UNSW communications. In the 2026 news release, Dr Trujillo states that there are companies producing coffee on an industrial scale and that the team is confident the ultrasound system can be scaled to meet those needs, delivering benefits in reduced processing times and energy use. In the 2024 cold brew work, he also told UNSW news that the technology can be adapted to existing espresso machines, suggesting a pathway for integrating ultrasound into current brewing hardware.
