The Production Process

Depending on the kind, tea goes through some or all the processes of withering, rolling, fermentation, and drying. These processes dry the tea leaves and produce the special characteristics of each kind of tea.

WITHERING
In the withering process, warm, dry air removes the moisture in harvested tea leaves, which are spread on racks. Machines reduce the time needed in the withering process, but lowers the quality of the tea by reducing the time for proteins and carbohydrates to break down.

ROLLING
After the withering stage, tea leaves are rolled to break up the cells, which speeds up fermentation. Traditionally, tea leaves were rolled in bunches by hand until they became twisted and broke into pieces. Rolling machines have a circular table in the center with a cone and "batten" slats, and a bottomless circle-shaped box with a pressure cap called a "jacket" on top of it. The table and the jacket rotate in opposite directions so that the tea leaves inside the jacket twist and roll over the cone and battens in a way similar to traditional hand rolling. 

FERMENTATION
Tea "fermentation," actually a series of chemical reactions, starts during the rolling stage when the tea leaf cells are broken, and continues when the rolled leaves are spread on tables or trays under controlled conditions. The most important reaction is the oxidation, which affects the taste, strength, and color of the tea. 

DRYING
In the drying stage, heat dries tea leaves and caramelizes sugars, adding flavor and producing the black color of fermented tea. Traditionally, tea leaves were dried over fire, but since the late 19th century, forced heated air has taken place of flame. In a mechanized drier, tea leaves are fed from the top into a large chamber as the hot air is blown into the chamber's bottom. 

After the tea has been dried, it goes through the packaging processes of grading and packing. 

GRADING
First, the tea leaves are sorted by size, shape, and cleanliness by mechanical sifters fitted with meshes of various sizes. Unwanted pieces are taken out by hand or by a mechanical extractor, and air is used to blow away dust, fibers, and fluff.




PACKING
Tea is packed in airtight containers, usually made of plywood and lined with aluminum foil and paper, to keep moisture out and preserve flavor.