What is caffeine?
Caffeine is found naturally in plants such as the tea plant Camellia Sinensis. Caffeine acts as a stimulant in humans but caffeine is also a natural pesticide in plants. That is probably why our good old tea plant loves it so much; Caffeine kills the insects that are trying to eat all those lovely tea leaves.
Does green tea contain caffeine?
Yes, green tea contains caffeine (just like all other teas), as all tea starts its life as a leaf from the same plant: Camellia Sinensis.
The average 8 oz. cup contains around 25mg of caffeine. The amount of caffeine which actually ends up in your body is a wide varying scale with many influencing factors such as age of leaf, water temperature, steeping time and many others.
The type of loose tea those leaves eventually end up as be it black tea, green tea, Oolong Tea or White Loose tea is influenced by which part of the plant the leaf is picked from, the age of the leaf and also what processing the leaves have been through once they are picked (roasted, rolled, steamed, sun-dried).