Pu-erh originated thousands of years ago in the Yunnan Province of China, where large-leaf tea trees (Dayeh) grow. Its history relates closely to the tea trade between China and other nations (notably Tibet), and it is named for the town from which it was originally sold en route to other countries (Pu’er City). It was originally compressed into shapes for more efficient transit, and it acquired its dark color and flavor due to natural fermentation in transit to its final destinations.
For many years, pu-erh has been aged. The aging process results in a slow fermentation, and it can take about 15 years for a ‘raw’ (unfermented) pu-erh to get the dark color and flavor that pu-erh drinkers desire. In the 1970s, a style of processing called shou processing (or ‘cooking’) was developed to expedite the fermentation process.
Shou processing eventually led to a pu-erh collecting/investment ‘bubble’ in the 1990s and 2000s. During the pu-erh bubble, many impostor pu- erh teas were made with tea leaves grown outside of the traditional appellation of origin (Yunnan). Prices skyrocketed, many collectors began to hoard their aged pu-erhs and the quality of new pu-erhs plummeted as production ramped up to try to meet demand. Fortunately, the pu-erh bubble collapsed and production has more or less returned to normal.
The Story of Pu-erh Tea
Until the turn of this century, few of us in the West had heard of pu-erh tea and, as more and more tea dealers started bringing in cakes and blocks and little balls of compressed tea buds, we struggled to make sense of terms such as raw or cooked, young or aged, compressed, and fermented rather than oxidized. It is a complicated type of tea about which there is a lot to know. So let’s start with the history that produced pu-erh tea more than 1,400 years ago.
During the days of the Tang Dynasty (618 to 907 CE), teas from Xishuangbanna in the south of Yunnan were being traded northwards through Yunnan province and then, via Sichuan, up to Tibet. High up, at 13,000 feet in Lhasa on the Tibetan plateau, the local people wanted to drink tea but could not grow their own and so were dependent on supplies arriving from China. What the Tibetans could produce, however, were strong, tough fast mountain ponies that China wanted for its armies. The trade increased and gradually more and more tea was transported up to Tibet along the winding, rocky, narrow Tea Horse Road to be exchanged each year for hundreds of ponies. The city of pu-erh in Yunnan province became the center of the local trade and so the teas became known as pu-erh teas.
The journey to Tibet took six to eight months through rain and mist, warm sun and cold winds. During the long journey, the tea often became damp or absorbed humidity, and this activated all the little microorganisms in the tea and provoked a slow bacterial fermentation. The microorganisms were in the tea because they live in the forests of southern Yunnan, settle on the leaves of the tea trees and are therefore captured during processing. So, over time, on its journey from Yunnan and while in storage in Lhasa, the natural fermentation process continued, changing the character of the tea, mellowing the astringent green grassy flavor of the young pu-erh to the smoother, fruitier flavor of the aged, fermented teas.
People began to recognize that the best pu-erhs, also known as dark teas, were those that had been aged for 10, 20, 30 or more years and, as consumption of pu-erh teas increased in China, and new demand came from Chinese refugees in Hong Kong in the 1950s, the tea makers in Yunnan began to realize that they needed to produce more tea.
In 1975, in order to speed up the fermentation process and make more tea available more quickly, a method of wet piling the tea was adapted from Guangxi province (where it had been used since the 18th century) to start making what is today known as shu or shou(cooked, ripened, and ripe) pu-erh (熟茶), whereas the traditional compressed and aged tea is referred to as sheng (raw) pu-erh (生茶).
To make sheng pu-erh, tea buds and leaves are picked, preferably from ancient semi-wild trees, withered in the shade for a few hours, panned at a low temperature to remove some of the water content, rolled by hand on bamboo baskets, and dried in the sun. Because the panning part of the process is not enough to kill off all the enzymes in the green leaf to prevent oxidation, as the tea dries slowly over a number of hours, a certain amount of oxidation does take place in the leaves and buds and turns them brown. The finished tea is called maocha (毛茶, rough or unrefined tea).
The maocha is then weighed out according to the size of cake to be made, steamed, shaped inside a linen bag to a neat round disc, pressed under a heavy stone or by hydraulic press, air-dried, then wrapped and stored in a room where the temperature and humidity are carefully controlled. The longer the tea is stored, the sweeter and smoother it becomes. Also, prior to pressing, a nei fei (內飛) is placed on the cake and during pressing embedded into the cake. The nei fei is a piece of paper that names the processing location and often contains other details about the tea.
The processing of shou pu-erh starts in the same way, with the manufacture of maocha. However, then, instead of being steamed, the maocha is mixed with water, heaped, covered, and stored in a humid, warm warehouse for several months. The covers are removed from time to time, the tea is mixed and turned, and the covers are then replaced. When it’s ready, the tea is dried and then sold loose or compressed into cakes in the same way as sheng pu-erh. Shou pu-erh is usually only aged for two or three years, and rarely longer than ten.
Connoisseurs often store and age pu-erh tea for decades, watching the flavors become more and more complex over time. Although it is most commonly found in cake or brick form, it is also available as loose leaves, sometimes aged in bamboo, but can also be found in rare, unique shapes, too.