Ultrafast cold-brewing of coffee by picosecond-pulsed laser extraction

Coffee is typically brewed with hot water, whereas cold brewing—credited with health benefits and fewer acids and bitter substances—requires hours to days. To achieve cold-brew coffee within minutes, this study applies an ultrashort-pulsed laser directly to a coffee–water suspension at room temperature, extracting caffeine and aromatic substances without bulk heating. Three minutes of picosecond laser irradiation yielded about 25 mg caffeine per 100 mL, comparable to traditional hot brews, while maintaining a cold-brew-like chemical profile. Liquid-phase alkaloids (caffeine and trigonelline), analyzed by reversed-phase LC-HRMS, resembled conventional cold brew more than hot brew. Headspace analysis via ITEX-DHS GC–MS indicated preservation of (semi-)volatile compounds, such as pyridine, in the absence of heating, contributing to cold-brew taste characteristics. This proof-of-concept demonstrates that ultrafast laser extraction can accelerate cold brewing by more than an order of magnitude while preserving key compositional attributes.

Anna R. Ziefuß, Tim Hupfeld, Sven W. Meckelmann, Martin Meyer, Oliver J. Schmitz, Wiebke Kaziur-Cegla, Lucie K. Tintrop, Torsten C. Schmidt, Bilal Gökce, Stephan Barcikowski