Ever drink decaf and wonder just how your coffee came to be decaffeinated? Experts say it can be tricky for consumers to find out just what method was used to supply them with a slightly calmer cup of joe. And yet one of the three most common ways to remove caffeine is thought to be harmful to the drinker's health, according to the German News Agency (dpa).
A relatively inexpensive approach is to dissolve the caffeine with chemical solvents such as dichloromethane or ethyl acetate. The method with ethyl acetate is considered to be a natural process, as this substance is also found in some fruit and vegetables.
Dichloromethane, on the other hand, is suspected of being carcinogenic. "How much solvent residue may be contained in decaffeinated coffee is determined by an EU directive," says food expert and gastroenterologist Sabine Hülsmann.
When it comes to dichloromethane, this is a maximum of 2 milligrams per kilogram of roasted coffee, according to guidelines in the European Union. These tend to vary in other areas, however. Finally, the carbon dioxide process does not require any solvents.
Here, the beans are flushed with liquid carbon dioxide under high pressure, in a method that binds the gas to caffeine particles to extract them from raw beans, and then, move the caffeine into another separate storage. The process has to be repeated several times.