White teas are not rolled or fermented and undergo a minimal amount of oxidation. Only the white leaf buds and very young silvery tips are picked. The young leaves may or may not be shaped before being dried. The new growth buds are dried immediately after the wilting process. They are not heated, rolled or crushed. The buds are left intact and thus give this tea its delicate floral aroma. The special processing of white teas helps preserve the original refreshing taste of the tea plant. White teas are typically expensive and their quantities are small in comparison.
Green teas undergoe the least amount of oxidation. The pickings of higher quality green teas include the first two leaves and the bud only. Green teas are quickly heated shortly after they are picked. The teas are either cooked in hot dry pans or with steam. Green teas may be rolled into small pellets as in Gunpowder tea or they may be left to dry separately. Good quality green tea has a fresh scent resembling hay their leaves should be greener rather than brown. They also posses a dull sheen and are dry and firm to the touch.
Oolong teas undergo almost the same processing methods as black teas although they have a shorter fermentation process or semi-fermentation. Their oxidation process is stopped somewhere between green and black tea and each tea manufacturer varies in the degree to which they ferment their teas. Oolongs are wilted either in the sun or indoors; some are tossed in bamboo baskets rip the edge of the leaf in order to help the sap to come forth. Next they undergo a partial oxidation, are pan cooked or baked, rolled, and finally dried again or fired. Oolong teas are considered one of the most difficult teas to make.
Black tea undergoes a substantial amount of care to arrive at its final destination. After being picked, tea is withered (dried) in the sun on mats or currents of warm air are blown over the leaves. At this point the tea looses approximately 60% of its moisture. The next stage is rolling; they can be torn, crushed, and or cut to allow their sap to react with the oxygen in the air. The following stage is fermentation. The rolled leaves are now spread out on tables and kept damp. This process can last between two to three hours. The oxygen in the air helps change the leaves color from green to copper red or dark brown. After fermenting the leaves are dried in hot air of 185°F (85°C) for approximately 20”. This stops the oxidization process so the tea will be a stable product that is long lasting.
Pu’erh teas are also called post-fermented teas. These teas undergo a second oxidation process. Green Pu’erhs are made from the spring harvest and are treated with bacterial cultures in a special process whereby microorganisms are added. Red Pu’erhs made in much the same manner as the green but the summer harvest is used instead. Both are often pressed into shapes or cakes and stored for months in cool conditions in much the same fashion as wine is vintage. Red Pu’erhs can be aged for a long time and will obtain a red color and an earthy or musty flavor. Pu’erh teas are gaining popularity throughout Europe.