Removing Caffeine from Tea

Decaffeinated tea, also known as decaf tea, is tea that has had most of its caffeine removed. Decaffeination processes are diverse, ranging from ones that are dangerous and have been made illegal, to ones that are totally safe and pose no health risks. At least one of the processes in use today involves a probable carcinogen, and the different processes also have different impacts on flavor, so it is important to know about each process if you are interested in buying decaffeinated tea.

Different decaffeination processes used on tea:

• CO2 / Carbon Dioxide - CO2 decaffeination uses highly compressed carbon dioxide gas, which becomes a fluid under pressure. CO2 is totally safe and is effective at removing caffeine. The CO2 process is good at preserving flavor; its main downside is that it is expensive.
• Ethyl Acetate - Ethyl acetate is a naturally occurring compound, common in fruit (and also occurring in small concentration in tea leaf). It is completely safe at the levels in which it remains in the tea after decaffeination. The ethyl acetate process is inexpensive, but it has the disadvantage of removing more flavor than other methods.
• Methylene Chloride / Dichloromethane - Methylene chloride, also called dichloromethane, is effective at extracting caffeine while leaving other flavors intact. However, it is a probable carcinogen and is toxic in large concentrations. Its use in decaffeination is legal in the U.S., but regulated by the FDA. Methylene chloride probably does not pose a large health risk in the low concentrations left in most decaf tea, but teas analyzed in the past have been found to have levels exceeding the legal limit. Companies using this process generally do not announce it due to the negative public perception of this chemical.
• Benzene - The original decaffeination processes used benzene as a solvent. Benzene is a dangerous chemical and can cause numerous health problems. It is not safe for use in decaffeination, and fortunately, its use for this process has been banned and discontinued long ago.
• Trichloroethylene - Another organic solvent that has been banned and discontinued for use in decaffeination.

In summary:

Of the most common methods for decaffeinating tea, CO2 decaffeination is generally the preferred method as it is safe and does a decent job at preserving flavor, but it is more expensive. Ethyl acetate decaffeination is safe and less expensive, but results in a greater loss of flavor. Methylene chloride is legal but regulated for use in decaffeination of tea, but is more marginal in terms of its safety. Other processes involving trichloroethylene and benzene were used in the past but pose serious health hazards and have been banned and discontinued.