Decaffeinated tea (or decaf tea for short) is tea with much less caffeine content than usual tea, or tea that does not contain any caffeine.
Caffeine is a stimulant that may cause sleeplessness in drinkers as it works on the central nervous system. Decaf tea does not have the same effect and some drinkers also find it healthier.
Tea made from the tea plant normally has 1.6% to 4.5% caffeine, depending on the level of fermentation. For tea to be classified as decaffeinated tea, at least 97% of the caffeine content must be removed.
True decaf tea - that is, completely caffeine-free tea - only applies to herbal teas, or tea not made from the tea plant. A popular choice is rooibos tea, made from the rooibos plant of South Africa.
Decaf tea made from tea leaves can come in both black and green tea varieties. Some green tea varieties may also have such low caffeine content that they qualify as decaffeinated green tea, even though they may not have undergone the decaffeination process.
There are two methods of processing that are permitted in the United States - the ethyl acetate process, and carbon dioxide process.
Ethyl acetate process of making decaf tea
The ethyl acetate process uses a mixture of ethanol and acetate acid, taken natural from fruit sources. The reaction from these two chemicals is able to create a decaf tea that is 99.9% decaffeinated.
Decaffeinated black tea is made using this method. While this method is very effective, it can also be quite harsh.
Carbon dioxide process of making decaf tea
The carbon dioxide process is the gentler of the two processes, and is used mainly for making decaffeinated green teas. It is also considered a natural method of making decaf tea.
The process uses supercritical carbon dioxide - an odorless, tasteless and inert gas which leaves no toxic residues. The process also takes place at room temperature, further protecting the product.