Tea (Camellia sinensis) is a species of evergreen that grows best in areas where the temperature never gets very high and can only grow where frost is totally absent, this means that tea is best grown in the tropical hills of China, India and Sri Lanka. On tea plantations the plants are kept pruned to no more than two meters in height. The harvest of tea comes from the new growth; generally a worker only plucks the terminal two leaves, since these have the best flavour. While the variety of tea is indeed very large, the majority of teas can be categorized simply as white tea, black tea, green tea and oolong tea. The differences in these teas are merely the means of processing. The leaves are withered indoors for 24 hours, after which the leaves are then rolled and broken or chopped this begins the oxidation of the phenolic within the leaves.
White Tea is not allowed to oxidise at all as the leaves are steamed, rolled and dried immediately.
Green Tea has little oxidization as the leaves are steamed, rolled and dried after picking.
Oolong Tea falls somewhere between Green and Black Tea, because the leaves are only partially oxidized before it is rolled and dried.
Black Tea is allowed to oxidise for two to four hours before processing.
Finally the fermented tea is fired, hence blackened, for 20 minutes to reduce the leaf tissue moisture to 3%. The quality of the tea depends greatly on the local climate, and the processing techniques. The flavour of the tea comes from the essential oil called theol, and the alkaloid theine, which is essentially identical to caffeine.
There are many herbal tea blends that made from the leaves, roots, bark, seeds or flowers of other plants, but most lack the one unique ingredient that has made tea so popular… caffeine.
