COFFEE WITH OR WITHOUT CAFFEINE @museum.de

For a long time, people didn’t know which substance was responsible for the stimulating effect of coffee. Then, coffee fan and poet Johann Wolfgang von Goethe suggested to the Hamburg pharmacist Friedlieb Ferdinand Runge that he might want to try and discover the substance concerned. In 1819, Runge succeeded in isolating pure caffeine from coffee beans: a white, odourless but toxic powder with a bitter taste.

The Roselius process developed by the coffee firm of HAG was the first decaffeination method to be used commercially. It was developed and patented by Ludwig Roselius in Bremen in 1905. Roselius had suspected that his late father, a heavy coffee drinker, had poisoned himself with caffeine. In the Roselius process, the beans are soaked in salt water, causing them to swell. The caffeine was extracted with benzene, a solvent which is no longer in use due to its toxic and carcinogenic effects.

Kaffee HAG sold its decaf coffee in the US under the brand name Café Sanka. But the company also wanted to include a coffee with caffeine in its range, so it added the Onko brand from 1950. HAG was one of the first businesses to opt for a uniform design in its advertising, using black and red on a white background. To hint at the health aspect, the firm chose a red heart and a life belt as its logo. The company was taken over by General Foods in 1979.

These days, the usual decaffeination process operates with dichloromethane or ethyl acetate as solvents. It’s crucial for the solvent to be completely extracted afterwards, especially if you’re using dichloromethane, since it’s suspected of being carcinogenic.

Another method uses carbon dioxide. Here, the soaked coffee seeds are rinsed with CO2 to dissolve the caffeine. The carbon dioxide is then allowed to evaporate.

All these decaffeination processes are applied to the green coffee beans. First, the beans are soaked in hot water. Then the caffeine is extracted with a solvent. The initial process is only able to extract part of the caffeine content, so the procedure has to be repeated several times to reach the 0.1 per cent, which is the maximum residual caffeine content prescribed by the EU.

The caffeine obtained through decaffeination is sold to drinks manufacturers or pharmaceutical companies.

If you’d like to know the method by which your coffee has been decaffeinated, you need to check the packaging. The more elaborate processes are usually described in detail.

In the meantime, the industry has bred genetically modified coffee plants that don’t contain caffeine. But to date, none of these caffeine-free coffee plants have been commercially grown.