There are two ways to decaffeinate coffee, commonly referred to as either
direct or indirect decaffeination. This means the solvents used to remove the caffeine
may directly or indirectly come in contact with the beans.In the past, methylene chloride was often used as a solvent.
This is called to cause cancer in humans, so is not used often. Another solvent, trichloroethylene, was found to be carcinogenic also, and is no longer used.
Indirect decaffeination is so-called because the beans never touch the solvent themselves.
Coffee beans are soaked in water to soften them and dissolve the caffeine. The water
containing the caffeine (and the coffee flavour) is treated with a solvent, heated to remove
the solvent and caffeine, and then returned to the beans. The flavours in the water are
reabsorbed by the beans, which are then dried.
The most widely used solvent today is ethyl acetate, a substance found in many fruits. When
your coffee label states that the beans are “naturally decaffeinated”, it is referring to this
process, specifically using ethyl acetate. Although it doesn’t sound like a natural process, it
can be labelled as such because the solvent occurs in nature.
A direct decaffeination process involves the use of carbon dioxide as a solvent. The coffee
beans are soaked in compressed carbon dioxide, which removes 97 per cent of the caffeine.
The solvent containing the extracted caffeine evaporates when the beans return to room
If your coffee is labelled ‘naturally decaffeinated’ or ‘Swiss Water Processed’, you can be sure
it contains no harmful chemicals.