Green Tea
is unfermented tea. One differentiates between two procedures:
the steamed tea, mainly employed in Japan, and the panfired tea used in
China where leaves are roasted in pans.
The steamed tea is
treated with hot water steam. For the roasted tea, the freshly plucked
leaves are dried for approximately 2 hours on bamboo sieves and,
subsequently, briefly roasted in wok-like, wood-buring pans. Due to
this brief heating, the fermentation is prevented. After this withering
process, the leaves are formed (e.g. rolled such as the Ping Sui
Zhucha), died further (such as the Bai Mu Dan) or roasted (e.g. Lung
Ching). Often, however, the leaves are put into a large rotating drum
where they are dried with the help of a heat stream of about 90°C and
loose a large amount of their weight. The withering process is of
utmost importance for the future aroma of the tea. Depending on the tea
variety and the tradition, the withering and roasting is perhaps
repeated a few times until the leaves are dried. Later, the tea is
sorted via sieves or, such as the premium teas from China, via hand.
Production process China
Plucking by machine.
Withering via ventilators or, with respect to premium qualities, in the
sun. A humidity of 30% is reached after 4-12 hours (pan-fried tea)
Heating or roasting. For 1-10 minutes the leaves are heated to 280°C in
the pans. Some teas are also heated mechanically in drums whose walls
are heated. The enzymes for the oxidation are converted and
deactivated. (Enzymes are proteins produced from living cells which
cause chemical reactions without consuming anything (biocatalysts)).
Drying for approximately 8- 12 hours.
Rolling in the machine in between brass plates for approximately 15 minutes.
Drying in rotating pans which are heated to 170°C.
Sorting via machines which separate different leaf sizes with
mechanically moving sieves. Premium qualities are still controlled by
hand.
Production process Japan
Plucking by hand or machine.
Steaming in cylindrical drums for approximately 2 minutes (= steaming tea).
Drying for approximately 30 minutes in rotating wooden drums at 55°C. Humidity lost: 50 %.
Rolling in the machine for approximately 5 minutes.
Drying for approximately 30 minutes via hot heat.
Polishing on plates which are heated to 90°C. For premium qualitites
this is done by hand. This makes the leaves flat and gives them a silky
shimmer.
Drying for approximately 20-25 minutes at 60°C. Rest humidity of the tea: 3-4 %.
Sorting takes place during the processing where a special processing machine is used to cut or form the leaves.