EU legislation states that decaffeinated coffee must have a caffeine content of less than 0.1% in the raw product and 0.3% in espresso drunk at the bar.
There are three methods for removing caffeine: with water, with pressurized carbon dioxide, and with solvents.
Let's look at them in detail:
- Water method: With this method, the coffee bean comes into contact only with water. In a first phase, the beans are treated with steam, immersed in water and washed, so that caffeine and other soluble substances present in the coffee disperse into the liquid. In a second phase, through a sophisticated technological process, caffeine is removed and the other substances are reintegrated into the bean.
- Carbon dioxide method: The beans are moistened with steam and water, then immersed in a cylinder in contact with the gas which, penetrating the coffee, frees it from caffeine.
- Solvent method: Caffeine is removed by immersing the beans in solvents such as methylene chloride or ethyl acetate. The beans are then treated with steam to remove solvent residues, dried and roasted. Methylene chloride came to public attention when it was discovered that it caused cancer when administered by inhalation to animals. However, negative effects on humans have not been demonstrated. The US Food and Drug Administration (FDA) continues to allow its use, stating that "any potential health risk is substantially non-existent."
