Black teas have slightly more than green. The small amount of caffeine in a cup or two of green tea is an amount and of a form which can help clear the mind and promote alertness. Too much tea, of course, and you wind up over-stimulated, as is the case with too much coffee. Because there is less caffeine in green tea than in coffee, however, and because it is in a form more slowly assimilated by the body, green tea provides a slower release of energy than the abrupt jolt one often gets from drinking coffee. You can decaffeinate your tea by pouring off the water after steeping the leaves or bag a minute or so, then re-adding hot water.
Caffeine is released in the first one to two minutes of steeping.
Decaffeinated green tea is also available in many places in tea bags. Types of Green Tea Green teas are as varied as coffees or wine. And, like coffee and wine, a taste and appreciation for green tea is generally cultivated over time. Give it more than one chance. Buying loose leaves generally gives you a higher quality of tea than the inexpensive green tea bags purchased in grocery stores.