Postfermented Tea
A very old Chinese specialty is Heicha, literally “black tea”. In the West we call it “postfermented” tea in order to avoid confusion with the Hongcha, the Chinese “red tea”, which is our “black tea”. These teas are produced following a stereotypical basic scheme; the exact procedure can however vary and is kept secret. The plucked leaves are withered, fired in a wok with moderate temperature, formed in rotary drums, sometimes also rolled and dried in the sun or with hot air. This half-finished tea is called Mao Cha, which means “hairy/unfinished tea”. Important here is that the enzymes in the leaves are not deactivated, natural fermentation and oxydation takes place after the processing. This is why the tea is called “postfermented”. Many of these teas are fermented before they are finally dried. In this process the tea is subdued to a fermentation that is specially accelerated by humans, the so-called Rengong Houfajiao, which makes it become old in a way. The Mao Cha is being piled up to heaps in which heat and moisture is at work. These piles are moved from time to time. In a process lasting for about three months, which consists in a fermentation induced by natural microorganisms, most of all bacteria and certain kinds of yeast and other fungi contained in the air, the chemical structure of the tea leaves is totally transformed. At the same time an oxidation with atmospheric oxygen takes place. In the end the tea is dried and sometimes heavily roasted. Those teas are dark red and black in leaf and cup from the beginning on, which leads to their name Heicha, black tea. Pu Er and Liu Bao teas can also be processed as Sheng Cha, which means “raw/living tea” without fermentation before being dried. Fermentation in this case only takes place through the microorganisms contained in the air after a certain time, causing the still greenish tea to get its dark colour. Strictly speaking those teas can only be called Heicha after a certain age (and hence state of fermentation). In the same way, Oolong teas that have been stored for a quite a while are sometimes called Heicha. The historical origins of Heicha are not clear, but quite probably this way of tea processing emerged soon after or even before the green tea production did.
Pressed forms
Tuocha, Zhuancha and Bingcha are all different pressed forms. The classic Bingcha, “Cake-Tea”, weigh seven Liang, which corresponds to about 350-375g. There are smaller cakes too, however. Tuocha, “Tear (shaped) Tea” are hemispheres weighing about 100, 250 grams or even more. Zhuancha, “Brick Tea”, are produced in different sizes. The right quantity of tea leaves to be pressed is first weighed, then this portion of dried leaves is softened with steam and formed by hand in a jute bag. The bag is then placed into a mould with a heavy stone on top. The tea is quickly pressed for a last time in a press into its ultimate form, then exposed to dry and wrapped into paper. In order to store these teas in the right way they need air, a good temperate room climate and some air humidity.