Could lasers put cold brew on a hot streak?

Not all that is cold is cool. Cold brew coffee, for example, is simply better than iced hot brew. If you don’t believe the studied opinions of millions of hipsters and millennials, then believe Technavio Research, which recently projected that the cold brew coffee market will grind out more than 26% compound annual growth between 2020 and 2025. If there’s one burnt bean that could sour this growth, it’s the fact that cold brew drinkers must either buy expensive, premade bottled products or plan their morning brew well ahead of time. Unlike hot coffee, cold brew takes 8 to 24 hours to steep.

Those who are able to plan that far ahead can enjoy fresh coffee that is less acidic and less bitter, and that retains the rich flavors of all of the volatile, aromatic chemicals that hot brewing processes release as their signature scent.

Courtesy of Anna Ziefuß, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE).

But why should only type A organized planners be able to enjoy a fresh cold brew in the morning? This was the question that percolated through the research of two scientific teams seeking faster cold brew methods.

The first team — encompassing collaborators from China, Egypt, and Turkey — used ultrasound to reduce cold brew preparation from 12 hours to one. They reported that the flavor of their brew was “good,” and said that ultrasound-assisted extraction methods are highly efficient for food and natural products. However, very limited research by Photonics Media left unanswered questions about whether the 200-W probe-ultrasound equipment used in the research would be too bulky for the kitchen area in most millennials’ studio apartments.

Subsequent research in Germany replaced ultrasound equipment with an Nd:YAG picosecond pulsed laser that delivered a repetition rate of 80 kHz and pulse energy of 125 µJ at 532 nm. As with ultrasound, the pulsed laser energy was able to fragment and release the essential coffee compounds without heating the mixture — all within 3 min, the time it takes for a drip coffee maker to fill its pot.

The scientists then used liquid chromatography coupled with a mass spectrometer to analyze their product. They found that its acidity level and caffeine content fell in between those of hot- and cold-brewed coffee.

Moreover, the coolness quotient of laser-steeped cold brew is sufficiently high that the researchers — led by chemist Anna Rosa Ziefuß and food engineer Tina Friedenauer, both at the University of Duisburg-Essen — are launching a spinout based on the LEoPARD project, which stands for “Laser-based Extraction offers Pure and Advanced Refreshment Drinks.” They envision a market for the technology at events such as weddings. But the technology could also be rented or licensed to coffee houses.

The two researchers could be on to something. Readers of this magazine will probably agree that LEoPARD cold brew is arguably cooler — figuratively, not literally — than ultrasound brews. This can only increase cold brew’s cachet in the vital hipster market, as drinking it would allow hipsters to demonstrate that they are “cooler than thou” when they could legitimately pontificate about how the scalable method of laser synthesis and processing of colloids unlocks the coffee’s flavors through fragmentation induced by thermal or electronic processes.

Do you want 2% foam on that venti half-caff, picosecond pulsed doubled-YAG laser brew?