All teas derive from the plant, Camellia sinensis. The numerous teas accessible throughout the world vary depending on the region in which they are cultivated, the soil in the area of cultivation, climatic parameters, time of harvest and the following post-harvest treatment.
White tea comes from the youngest buds and leaves from the tea plant. It is the least processed variation of tea, since the post-harvest treatment only consists of steaming and drying. Brewing white tea will produce bright shades, most often associated with very subtle and complex aromas and a bright cup.
During the post-harvest handling of green tea the leaves are heat-treated to stop the oxidation, then rolled and dried, when the humidity of the leaves is low enough. In China the leaves are traditionally dried in pans, where as in Japan the leaves are steamed. Green tea produces a yellow-green and dark green cup and the aromas are typically associated with toasted and grassy notes.
Black tea is produced by rolling dried tea leaves in order to break down the cell walls of the leaves to release enzymes and initiate changes of color. After the oxidation the leaves are dried and the easily recognizable scent and aromas associated with black tea appears. This process also provides black tea its characteristic body and mouth feel once being brewed.
Oolong tea is in the borderland of green and black tea. The post-harvest handling consists of a partial oxidation prior to drying in pans. The amount of oxidation can vary from 12-20% in the Chinese Oolong teas and up to 60-70% in the Taiwanese Oolong teas. Thus there is an interesting spread between the bright and light and powerful, highly aromatic and sweet teas.
Though the name may suggest a content of leaves from the tea plant, is it not the case of herbal teas. Herbal teas, or herbal infusions, are brewed from a selection of ingredients like dried fruits, berries, flowers and of course herbs.