Pu’er or pu-erh is a variety of fermented tea traditionally produced in Yunnan Province, China. In the context of traditional Chinese tea production terminology, fermentation refers to microbial fermentation (called ‘piling’), and is typically applied after the tea leaves have been sufficiently dried and rolled. As the tea undergoes controlled microbial fermentation, it also continues to oxidize, which is also controlled, until the desired flavors are reached. This process produces tea known as 黑茶 hēichá (lit. ‘black tea’) (which is different from the English-language black tea that is called 红茶 hóngchá (lit. ‘red tea’) in Chinese). Pu’er falls under a larger category of fermented teas commonly translated as dark teas.
In a very general definition, loose leaf tea is tea that does not come prepackaged in tea bags. Because the leaves are not crammed into a tea bag, the tea maintains a higher quality and aroma while offering the best possible health benefits. The drinker places the tea leaves inside of a steeping ball, infuser basket, french press, tea strainer, or some other infuser to prepare the tea.
Pu-erhs are the only truly ferment teas and they are made in the remote Yunnan Province (where the first tea plants were found). For the traditional method (aka green, raw, and sheng), the tea leaves are made and then stored. Then naturally occurring yeast react with the dry tea leaves, creating new and changing aromas and flavors. Sort of like sourdough bread, however it takes years and decades. For this Pu-erh, the aging and fermentation process has sped up. The Chinese have used the “wo dui” (the moist track). They pile the oxidized leaves into a heap in moist rooms, where the fermentation process is accelerated. This tea can brewed several times, for each additional brew, please steep tea an extra 15-30 seconds.
Maocha or rough tea
The intent of the maocha stage (青毛茶 or 毛茶; literally, “light green rough tea” or “rough tea” respectively) is to dry the leaves and keep them from spoiling. It involves minimal processing and there is no fermentation involved.
The first step in making raw or ripened pu’er is picking appropriate tender leaves. Plucked leaves are handled gingerly to prevent bruising and unwanted oxidation. It is optional to wilt/wither the leaves after picking and it depends on the tea processor, as drying occurs at various stages of processing. If so, the leaves would be spread out in the sun, weather permitting, or a ventilated space to wilt and remove some of the water content. On overcast or rainy days, the leaves will be wilted by light heating, a slight difference in processing that will affect the quality of the resulting maocha and pu’er.
Relatively young raw pu’er; note the grey and dark green tones
The leaves are then dry-roasted using a large wok in a process called “killing the green” (殺青; pinyin: shā qīng), which arrests most enzyme activity in the leaf and prevents full oxidation.:207 After pan-roasting, the leaves are rolled, rubbed, and shaped into strands through several steps to lightly bruise the tea and then left to dry in the sun. Unlike green tea produced in China which is dried with hot air after the pan-frying stage to completely kill enzyme activity, leaves used in the production of pu’er are not air-dried after pan-roasting, which leaves a small amount of enzymes which contribute a minor amount of oxidation to the leaves during sun-drying. The bruising of the tea is also important in helping this minimal oxidation to occur, and both of these steps are significant in contributing to the unique characteristics of pu’er tea.
Once dry, maocha can be sent directly to the factory to be pressed into raw pu’er, or to undergo further processing to make fermented or ripened pu’er.:208 Sometimes Mao Cha is sold directly as loose-leaf “raw” Sheng Cha or it can be matured in loose-leaf form, requiring only two to three years due to the faster rate of natural fermentation in an uncompressed state. This tea is then pressed into numerous shapes and sold as a more matured “raw” Sheng Cha.