A pilot result from Francisco Trujillo's group at UNSW Sydney replaces the boil of conventional espresso with acoustic cavitation, and a blind panel of 100 coffee drinkers could not distinguish the cup from a traditional shot.
The energy cost of espresso has always been hidden in plain sight: nearly a litre of boiling water, pushed through finely ground coffee at nine bars of pressure, for a 30-millilitre shot. That heat is the load. A team at UNSW Sydney has now shown a way to produce the same drink without it, brewing espresso-strength coffee with room-temperature water and ultrasonic sound waves in under three minutes, and cutting energy use by about 75% in the process. In a blind tasting reported by the researchers, 100 coffee drinkers could not tell the result apart from traditionally brewed espresso (Refractor summary of UNSW work).
The work, led by Dr Francisco Trujillo in UNSW's School of Chemical Engineering, replaces the thermal and pressure stages of conventional espresso with acoustic cavitation. High-frequency sound waves generate microscopic bubbles in the water; the collapse of those bubbles does the work that heat and pressure normally would, extracting the coffee's flavour and aroma compounds at room temperature. According to the UNSW team, the brew takes under three minutes, and the resulting cup matched a conventional espresso in a 100-person blind panel.
The energy figure is the part that matters most. Espresso machines spend most of their input power heating water to around 90°C, and that cost scales linearly with volume. A 75% reduction in brewing energy, if it holds up under independent testing, is a meaningful cut for any operation that makes coffee in bulk. Cafés are the visible face of espresso, but the bulk of the format's energy load sits upstream: in the factories that produce ready-to-drink (RTD) espresso, canned and bottled coffee, and the concentrated coffee bases that end up in chain menus. Replacing a thermal extraction step with a room-temperature acoustic one is, in industrial terms, a different process altogether, with lower utility demand, simpler heat management, and a smaller boiler footprint.
The taste result travels with the energy claim rather than after it, because that is the harder hurdle. Hot extraction is not just a path to flavour; it is one of the mechanisms that produce espresso's characteristic body and aroma. A blind panel that fails to distinguish the two is a real signal, not a marketing footnote. The caveat is that the panel and the tasting protocol belong to the UNSW group, and the sensory claim should be read as primary-team-reported until the peer-reviewed methodology is independently examined.
Scale is the other honest limit. This is a pilot result from a single research group. The path from a university rig to a production line at an RTD bottler runs through replication, third-party sensory work, food-safety validation for an acoustic extraction, and equipment economics. The peer-reviewed record confirms the core finding — espresso-strength coffee brewed at low temperature in 2–3 minutes with lower energy consumption, published in the Journal of Food Engineering (2027) — but commercial deployment is not yet on the table. What is in the record is a credible proof of concept that the thermal step in espresso is removable, and that the result can survive a panel of 100 drinkers.
What to watch next is whether the energy and sensory results replicate outside Trujillo's lab, and whether the RTD segment, which buys flavour consistency and energy efficiency in the same procurement contract, moves first. If it does, the espresso in a can on a supermarket shelf is the place this technology will reach a consumer, not the espresso bar.