Tea usually refers to a single species of plant, camellia sinensis, native to Southeast Asia and all tea from this plant contains caffeine. Green, black, oolong and white tea all come from camellia sinensis. Most herbal teas come from a variety of different plants and do not contain caffeine, however, there are exceptions such as yerba mate or guayusa. The amount of caffeine varies depending on the amount of time and temperature the tea leaf is infused, as well as the type of tea. In general, black tea contains the most caffeine.
A cup of normal black tea contains 40–50 mg of caffeine, roughly half the content of a cup of coffee. Sometimes even that amount may be too much for those sensitive to caffeine. The caffeine in tea has a different effect than caffeine in coffee, as it doesn't produce a jolt or let down. This is due to the combination of caffeine and L-theanine uniquely found in the camellia sinensis plant.
L-theanine, an amino acid, is only found in tea and some mushrooms. It relaxes the mind without inducing drowsiness, hence the calming effect often attributed to tea. This combination of caffeine and l- theanine is how tea improves mental focus.
The problem is not all of your favorite specialty teas come in a decaffeinated version. The only choice readily available for decaffeinated tea is a bland, stale version of a low grade commercial black or green tea.
There is a method to reduce the caffeine in tea at home using the quick rinse method. This is safe and avoids the use of chemicals to remove caffeine. Commercially available decaffeinated tea removes the caffeine using either liquid carbon dioxide or repeatedly rinsing with methylene chloride or ethyl acetate. That just doesn't sound appealing to me so I prefer the natural process of removing caffeine using water.
Simply discard the tea from the first brew after a three-minute infusion. This removes 46 to 70 percent of the caffeine from a cup of black tea. It is important to note the discarded first brew must be made at the recommended brewing temperature for that specific tea. Black tea brews at 212 degrees Fahrenheit.
Now you can re-use your washed tea leaves for a lower caffeinated brew, although it will not technically be decaffeinated. True decaffeinated tea has 97 percent of the caffeine removed, or 4 mg of caffeine per serving.
Using the quick rinse method will yield an average of 18 mg of caffeine per serving. This is usually enough of a reduction for those wishing to moderate their caffeine intake. You can steep most loose leaf teas a second or even third time. If you use a high quality specialty loose leaf tea, you will not loose flavor in subsequent brews.
This information is based on the Asbury College Study on Tea Caffeine.
Until next time - drink tea and carry on dear tea friends!