Decaffeinated (decaf for short) tea is tea leaves that have undergone a process that removes most of the caffeine. By law, tea labelled “decaffeinated” must contain less than 2.5% of its original caffeine. Because of this law and limitations in the process, no decaf tea is actually caffeine free.
How is Tea Decaffeinated?
There are four primary methods to decaffeinating tea in the modern world. Methods well known to use toxic chemicals have been banned, but that doesn’t mean these four used currently are safe.
Here’s a basic rundown of each process and why some tea drinkers are skeptical of them.
Carbon Dioxide – This process is considered to be the safest and the most preserving of the tea’s flavors. Pressurized liquid carbon dioxide attracts the small caffeine molecules out of the tea leaves and leaves the larger molecules responsible for flavor behind.
Ethyl Acetate – Tea leaves are soaked in a ethyl acetate, a solution that occurs naturally in tea leaves and some fruits. Though the process is not associated with health risks, it is well known to decay the flavor of the tea. Some tea drinkers claim this method can result in a chemical taste.
Methylene Chloride – Tea leaves are often soaked in methylene chloride, which bonds with the caffeine molecules. The tea leaves can be strained out with most of the caffeine left behind. Methylene chloride is widely considered unfit for consumption, but the process leaves traces of the compound on the tea leaves. This method and its safety is in much dispute, though it is widely used.
Water Processing – This process is generally associated with coffee beans, but some tea producers have begun using it on their tea leaves. Hot water extracts the caffeine, along with flavors and almost everything else. The water is filtered through a carbon filter, which catches the caffeine molecules. The water is returned to the tea leaves, where they soak up the extracted flavors again. Though safe, it is widely unexplored in the tea realm.