Green tea is extracted from the leaves of the Camellia sinensis plant. The benefits of green tea are numerous, and it is often viewed as a healthier substitute for caffeinated drinks. According to the USDA, an ounce (29.6 g) of green tea that is brewed from bags contains 5 mg of caffeine. On the other hand, an ounce (29.6 g) of coffee that is brewed from grounds and prepared with tap water contains 18 mg of caffeine. So, green tea cannot be included in the category of beverages that are free of caffeine. However, the presence of caffeine doesn't negate the health benefits of this beverage. The following sections provide information on green tea. A normal dry leaf of the green tea may contain more caffeine than coffee by dry weight. However, it is generally found that a cup of coffee contains more caffeine than a cup of green tea, or any tea for that matter. The main reason behind this is that the tea leaves are strained before serving, by which some portion of the caffeine is discarded along with the leaves. This is not done in case of coffee, which is why the caffeine content of coffee is higher. So, the caffeine content is dependent on the quantity of leaves that are used. Other factors that determine the caffeine content in your cup of green tea include: Size and Type of the Tea Leaf Caffeine content in green tea depends largely on the size and type of the tea leaf. Larger the size of the leaf, lesser is the caffeine content. The highest levels of caffeine is found in a branch's top two leaves and bud. On the other hand, leaves that are picked from the lower parts of the bush have been found to have less caffeine. Preparation Procedure An average cup of green tea, in which the leaves are steeped just once, can have as much as 32 mg of caffeine in 100 ml of water. If the strained tea leaves are reused, the preparation will contain only 12 mg. The caffeine content would reduce considerably if these leaves are used again. Moreover, green tea prepared on a high flame, or in a wok, will have less caffeine than the one prepared on slow flame. Shape and Size of the Container The size of the container will also influence the caffeine content. Larger the area of circulation, more caffeine gets drawn from the green tea leaves. As compared to black tea, coffee, or soda, green tea has a very steady stimulating effect due to the presence of caffeine and two caffeine metabolites (caffeine-like substances) called theophylline (stronger stimulant substance than caffeine) and theobromine (slightly weaker stimulant than caffeine). An average cup of brewed coffee can contain between 60 to 160 mg of caffeine. A can of soda may provide 40 to 70 mg, while a cup of brewed black tea provides 20 to 90 mg. On the other hand, the amount of caffeine in green tea is in the range of 6 to 35 mg only. The concept of decaffeination, which is a process for removing caffeine from green tea, is prevalent in the west or even China. However, it is unheard of in Japan, which is the home of green tea. Caffeine, along with its other metabolites, is the reason behind the beneficial nature of this tea. The process of decaffeination robs tea leaves off these metabolites, obviously along with caffeine itself. So, does it mean that caffeine is a mandatory constituent of green tea? Not necessarily. Take some high quality loose leaves of Japanese green tea. Ensure that the leaves are very fresh, preferably from the first harvest. As almost all the caffeine is extracted during the first infusion, dump the first infusion and then immediately re-brew using the strained tea leaves. Although, doing this will rid the tea of its aroma, it will surely taste better than the best decaffeinated green tea. On a concluding note, green tea is not free of caffeine and its metabolites. The benefits of green tea revolve around these constituents. Thus, it is advisable to substitute it for coffee or tea. Also, reap the benefits of this truly wonderful tea by having it in moderation.