Tea is generally divided into categories based on how it is processed. After picking, the leaves of the tea plant (Camellia sinensis) soon begin to wilt and oxidize unless immediately dried. An oxidation process is triggered by the plant’s enzymes that causes the leaves to turn darker. This darkening can be stopped at a predetermined stage by heating, so in the production of black teas, halting by heating is carried out to produce the desired tea.
wilted and unoxidized
Unwilted and unoxidized,
but allowed to yellow
Unwilted and unoxidized
Wilted, bruised, and
partially oxidized
Unwilted and unoxidized
Wilted, sometimes crushed, fully oxidized.
Called [hóngchá] in East Asia