Shou Puer is a relatively new processing technique. Possibly the oldest known method for creating a puer, and the first step toward creating any modern puer, is the Shai Qing Mao Cha method shown here in a video. This makes a loose leaf sheng or raw puer that originally made Yunnan famous for its tea. Traditionally a couple is given this tea at marriage which they then store as a retirement present to drink in old age, to impart health and help them relax. Of course the idea of waiting twenty or more years for a tea to properly cure requires more patience than many people have. It relegates the tea artisan to a niche market, because traditional collectors were only old wealthy families in Tibet, Guangdong, Hong Kong, Taiwan and Japan. Some larger farms have storehouses of sheng puer dating back fifty years, but these teas are then sold at auction for a high price. So the market was kept small, with new tea seldom bought at retail because of its bitter tannins and old tea priced out of the market. In the 1970's Yunnan puer makers began to experiment with an artificial aging process in order to make their tea marketable quicker. The idea was to place the Shai Qing Mao Cha in "saunas" - hot and damp rooms - which accelerated the natural process of anaerobic fermentation by which sheng puers naturally age. In six months of "sauna" a green grassy and astringent raw puer leaf could be transformed into a sweet or earthy, mellow infusion.
This rapid aging changes the puer taste characteristics and is not without dangers. The shou puer chambers must be sterile, as high heat, humidity, and darkness are environments in which many human pathogens thrive. Dangerous fungi and mold can grow in these "saunas" and the shou puer spoiled. After such an investment of tea and time, so-called inferior products are rarely discarded but rather sold at a cheaper price to be offloaded on unsuspecting and ignorant customers. Even when the shou puer aging process is carried out by a master the resulting tea develops unique flavor characteristics and no longer has the complexity in taste of a naturally aged puer. High heat deactivates some bio-activity in the Shai Qing Mao Cha, and by forcing the reaction in cooked puer many secondary and even tertiary flavor inducing reactions do not occur. As a result cooked or shou puer will tend toward a sour, sweet or loamy taste whereas old raw develops a range of astringent to mulched hay overtones, as the tanins and fats naturally form simple and complex sugars. Raw puer can age unevenly and vary more year to year than a cooked puer, and some raw puer's only taste wonderful after twenty to thirty years. Sheng or raw puer also develops distinctive psychoactive properties after about fifteen years of aging. Shou puer also can benefit from aging, and often a mixture of various tea buds and leaves are mixed to increase the flavor range in higher quality shou puers. Both types of tea can yield wonderful and inspiring tastes, maybe something like comparing impressionistic and renaissance paintings, the latter's crisp lines a metaphor for sheng puer properly aged.
Also, it should be noted, age alone cannot guarantee a young tea grown in worn-out soil will become a good tea. Recently a number of old teas from 1990 central Yunnan grown around Dali have come to market with a bitterness that no amount of age will remove.
