Bye, bye, stimulant: how to decaf the coffee bean

_{^{02.09.2020 I Vera Schmies}}

What comes to your mind, when you think of decaf? A late evening cup, without a subsequent sleepless night? Dallmayr, Jacobs, Melitta or Lavazza? Probably, even the most enthusiastic coffee lovers wouldn't have guessed: thyssenkrupp is part of the team.

thyssenkrupp and decaffeinated coffee? You’ve heard right. Our experts play a decisive role in taking the caffeine out of the coffee bean gently and efficiently – turning the heart-friendly pleasure into reality.

How to decaf the coffee bean?

Have you ever wondered how to decaffeinate a coffee bean? By boiling? By shock freezing? Or by using a tweezer?

In our way of decaffeinating, carbon dioxide plays the main role. It’s the substance that we all know as the fizzy-maker in mineral water. In this case, however, the CO₂ has a very special characteristic: it’s supercritical. And thus, an ideal partner for the decaffeination process in our experts’ laboratories.

Supercritical fluids: Between two worlds

In this case, supercritical has absolutely nothing to do with exaggerated perfectionism. Carbon dioxide belongs to a group of substances that can reach a supercritical state, one in which no one can say whether it is liquid or gaseous. In technical terms: It is above a critical temperature and pressure – almost as dense as liquid, but as thin as gas.

This suspension between two states of matter offers a lot of advantages that shape our daily life. Thanks to supercritical fluids, for example, we can extract natural flavors from spices and herbs. Pharmacists also make use of the method. Just like the caffeine-free experts at thyssenkrupp.

Under pressure: coffee without caffeine

There are many supercritical fluids. However, for decaffeination, carbon dioxide is the perfect match: it is readily available, inexpensive, non-toxic or explosive, and is not an organic solvent. Organic solvents are solvents that consist of organic compounds. The most common organic solvents are alcohols.

To extract the caffeine, our experts treat the coffee beans with water at gentle temperatures below 100 degrees Celsius. Via a high-pressure pump, they then conduct the carbon dioxide as a solvent into the pressurized extractor. There, the supercritical substance washes around all the beans. Thanks to its special state, it works together with water to release pure caffeine from the bean. Our experts can reuse the carbon dioxide during the next extraction.

Supercritical fluids are true all-rounders

Supercritical fluids are helpful for many aspects of our daily lives. The pharmaceutical applications are particularly interesting because microscopically small micro or nanoparticles with very specific average sizes can be produced or even modified with supercritical fluids. Especially for the development of new drugs with exact and controlled properties, the technology is worth its weight in gold.

Supercritical CO₂ even acts as a favorable drying agent for new and exciting high-performance insulating materials: so-called aerogels offer significantly better insulating properties than conventional insulating materials. This is important when it comes to critical points in building construction, for example. That’s why supercritical fluids are true all-rounders.

By the way: thyssenkrupp is the world leader in plants and processes in which supercritical carbon dioxide is used as an extraction agent. So the next time you drink your decaf, you know where the good taste comes from.