A derivative of the Camelia sinensis plant, has experienced a recent surge in its popularity due to its antioxidant properties. Oolong, green, and white teas also come from the same shrub as black tea; however, black tea is less oxidized and has a stronger flavor than its counterparts. When it comes to processing black tea, the Camelia sinensis assamica, a variety that has larger leaves, is traditionally used.
When leaves are harvested for black tea, air is blown on them to cause the leaves to wither. Next, the leaves are processed in one of two ways: the crush, tear, curl (CTC) method or the orthodox method. The CTC method yields machine-processed leaves that are of a finer texture that is typically used in tea bags. A rotovane is often used to cut the leaves prior to processing. Next, the pre-cut leaves are fed into a CTC machine, which shreds the leaves and utilizes contra-rotation rotors to further cut and tear the leaves into fine particles.
Watch B.W. Cooper take us through a tea processing plant and explains the means by which black tea is created.
The orthodox method may be done by machine or by hand. High quality teas are processed by hand. The orthodox method usually yields higher quality teas as the leaves are allowed to oxidize completely. Withered leaves are rolled mechanically or by hand. When the mechanical method is elected, the leaves are rolled on a rolling table and cut with a rotovane. The rolling process results in a mixture of broken and whole tea leaves, which are then sorted, dried, and oxidized. At this point, the tea leaves may be introduced into the CTC process to be further cut into fine particles and dust.
After being rolled and cut, depending on the elected technique, the leaves are oxidized in an environment in which the temperature and humidity are controlled. The oxidation process is referred to as fermentation although no actual fermentation takes place. Tea leaves and particles may be oxidized on a conveyor belt with adjusted airflow to create ideal conditions or on the floor. Timing from the rolling stage onward must be carefully monitored as oxidation begins at the rolling stage and continues throughout. The level of oxidation ultimately determines the quality of the tea.
The tea leaves are dried to suspend the oxidation process. Next the leaves are sorted based on size ranging from whole leaves, broken leaves, and fannings, to dust. The tea may be further sub-graded based on other characteristics. Finally, the leaves are packaged and labeled for consumers, who will eventually buy black tea online (see My Life Inc), or at tea and coffee shops, and in stores.