Caffeine occurs naturally in more than 60 plants, including Camellia Sinensis.
Several methods are used to remove caffeine from its natural sources. There are three methods of decaffeinating Teas: Methylene Chloride, Ethyl Acetate and CO2 (Carbon Dioxide).
In the first two, the Tea leaves are first steamed for 30 minutes and then repeatedly rinsed with either Methylene chloride (chemical used as a solvent) or Ethyl acetate (chemical found naturally in many fruits) for about 10 hours. The solvent is then drained away and the Tea leaves steamed for an additional 10 hours to remove residual solvent. Although effective, these methods also take out about 60% of the polyphenols (antioxidants).
To decaffeinate using carbon dioxide (CO2), water-softened materials are “pressure cooked” with the gas. In the carbon dioxide method, the caffeine is stripped directly from the Tea leaves by a highly compressed semi-liquid form of carbon dioxide. Pre-steamed Tea leaves are soaked in a bath of supercritical carbon dioxide (transition from liquid to gas). It becomes a solvent with its small, nonpolar molecules attracting the small caffeine molecules. Since flavor molecules are larger, they remain intact, which is why this process retains the flavor of the material better. After a thorough soaking for around ten hours, the pressure is reduced, allowing the CO2 to evaporate, or the pressurized CO2 is run through either water or charcoal filters to remove the caffeine.
Caffeine is not removed completely using any of these methods, but usually a product can be labeled decaffeinated when the caffeine levels are not above 2.5 percent of the product. When separated from its sources, caffeine is a white, bitter-tasting powder and it is used manufacture other products, such as medicines and soft drinks.
Nowadays, there are plenty decaffeinated Teas available (do not confuse these with tisanes who are naturally caffeine-free) but these are usually very poor quality. If you are concerned about your caffeine intake we suggest the following home made decaffeinated process:
- Heat the water to the right temperature depending on the Tea
- Cover your Tea with the heated water and brew for 30-45 seconds
- Discard the water
- Re-infuse the same Tea leaves again with fresh heated water and let it infuse for the correct time
As most of the caffeine comes out of the Tea within the first 30 to 45 seconds that will take out up to 20% of the caffeine and you end up with a home made decaf Tea.
Happy Tea Break.