Cold brew coffee brewed with lasers? Thank you Big Bang Theory!

“Nobody wants to wait 12 or 24 hours for a cup of coffee,” says Anna Rosa Ziefuss, the German scientist who has done the impossible: brewing cold brew coffee in a record time of three minutes instead of a half day.

Its secret ingredients? A laser. And endless episodes of The Big Bang Theory.

Ziefuss is a scientist in the department of technical chemistry at the University of Duisburg-Essen in Germany. There, his colleagues use ultra-short-pulse lasers to synthesize and process colloids, microscopically insoluble particles suspended in liquid. Colloids are typically used as thickening agents in everything from lubricants to beauty lotions. Usually, Ziefuss and his colleagues work with inorganic materials, such as gold or platinum. “Laser processing of organic materials like coffee is a rather new area of ​​interest, at least in our group,” she says. But when his thesis supervisor, Stephan Barcikowski, encouraged his group to “think beyond their own research,” his brain turned to caffeine.

“At the time, cold brew was very popular in our work group,” she recalls. However, like anything that requires planning ahead, people have simply forgotten to brew it early enough to drink it later. Strange as it may seem, given that Ziefuss has been working with lasers all day, she discovered the quick cold brew solution that lies in another interest: The Big Bang Theory TV series.

“Actors irradiate everything possible with a laser,” she says. And she had lasers and water and coffee. The rest is this story.

On the left is the optics used to magnify the laser beam. On the right, the container that contains the coffee powder dispersed in the water. The entire solution is stirred. The white spot shows the area where the laser meets the ship. [Photo: courtesy Anna Rosa Ziefuss]

A clever method

Cold brew is considered by many to be a superior coffee extraction process, although it really depends on your taste buds. Ziefuss herself admits that at home she prefers to drink hot coffee made in a French press. But it’s as much a matter of taste as it is of brewing method; most of the time, she doesn’t have the patience or the foresight to brew a cold brew.

Making cold brew coffee is quite simple. Basically, you do this by putting ground coffee in a cup with room temperature or cold water, leaving it there for 12-24 hours, then straining it to remove all the coffee particles. It’s just brewing without a high temperature, which makes hot brew coffee so fast.

Ziefuss’ idea was “to decrease the size of coffee powder via pulsed lasers [to] increase the contact surface of the micro-powder with water.

Increasing the surface area of ​​a substance to speed up chemical reactions is not a new idea in itself. If you’ve ever drunk Hudson whiskey, you’ve actually tasted this concept’s product. As its founder and distiller, Ralph Erenzo, once told me, they sped up the aging process of whiskey by chance, using smaller barrels which increased the surface to liquid ratio, effectively increasing the contact area. for liquid (a happy accident born of not having enough money to buy big barrels when they were launched). Additionally, micro-etching the interior of the barrels further increases the surface area of ​​contact, further accelerating the chemical reaction that occurs when alcohol interacts with charred wood. The process with coffee and lasers is very different from that of whiskey and oak, but it has the same effect: an increased contact surface which results in a faster chemical process.

Ziefuss and his colleagues used an ultrashort-pulse laser from the lab, arranging a series of optical lenses to magnify the beam and aim it at a container containing the coffee powder. While regular cold brew remains intact for several hours, in Ziefuss’ method the solution is stirred and then the pulsed laser fires on the container. Just three minutes later, they filter the solution through a commercial coffee paper filter to separate the excess coffee powder.

The result, as described by Ziefuss and his colleagues in an article published in Nature, is a perfect cup of cold brew coffee with the same properties as traditional coffee. Their chromatography and spectrometry data showed no statistically significant difference between the two methods. And the pH value, which “is associated with positive effects, such as reduction of gastrointestinal symptoms” like intestinal irritation (you know what I’m talking about), was also basically the same.

Beyond these technical tests, the laser coffee tasted as smooth and delicate as cold brew, Ziefuss says.

[Photo: courtesy Anna Rosa Ziefuß]

The future of coffee, tea and more

As exciting as instant cold brew coffee can be, Ziefuss says her laser method can be applied to all kinds of brewed foods and beverages, and that she and her colleague Tina Friedenauer want to bank on it. They are creating a startup to further develop and market their method. “We’re still early days and believe it will take a larger portfolio of extracts before entering the market,” she says. “Coffee was just the beginning, and we are currently investigating laser extraction of tea and matcha.”

The result could be a compact machine no bigger than your average Nespresso. “The heart of such a machine is, for sure, the laser system,” she says. “We believe that a pulsed laser flavor component extraction machine can be the size of an automatic coffee machine.”

They don’t have a timeline for this magic box yet, but Ziefuss thinks the device could fit well in cafeterias. And while a home-sized model isn’t the first step in their business plan, that may change later if there’s a market for such a device. I would definitely like one in my kitchen. I really want to drink laser coffee.

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