chinese traditional manufacture process. As soon
as the newly picked leaves reach the factory, processing begins.
WITHERING
The leaves are thinly spread to wither either naturally (where
the climate is suitable) or by means of heated air forced
over the withering racks. The object is to evaporate as much
of the tea leaf's water content so that the leaf becomes pliable
like soft leather gloves.
ROLLING
From the withering-racks the soft, green leaf passes to the
rolling machinery where it is twisted and rolled to break
up the leaf cells and release the juices which give the tea
its flavor. The first important chemical change starts here
when the juices which remain on the leaf are exposed to the
air and development of the essential oil begins.
ROLL-BREAKING
From the roller the tea emerges as twisted lumps which are broken
up by coarse mesh sieves or roll-breakers. The fine leaf which falls
through are taken to the fermenting rooms, while the coarse leaf is
returned for further rolling.
OXIDATION
The oxidation which started in the rollers is completed in the oxidation
room. Here the tea leaves are spread on cement or tile floors (sometimes
glass or cement tables) in a cool, damp atmosphere. The leaves undergo
further chemical change through the absorption of oxygen, and turn
bright copper color, like a new penny. It is this process of oxidation
which distinguishes the black teas, almost universally drunk in the
United States today, from what are known as green teas.
The Making of Formosa Oolong (Taiwan wu long tea) ,From
YouTube
DRYING OR FIRING
The purpose of this is to arrest further oxidation, and to dry the
leaf evenly and thoroughly without scorching it. The automatic tea
drier consists of a large iron box inside which the leaves, spread
on trays, travel slowly from top to bottom while a continuous blast
of hot dry air is forced into the box. Careful regulation of the temperature
and of the speed at which the trays move is the main factor in successful
firing.
Wu Long Tea is a compromise between black and green tea. The leaves
are only partly oxidized. They turn a greenish brown.