Post-fermented Teas Hei Cha 黑茶

20. 08. 2024

Dark tea (Hei Cha 黑茶) is post-fermented tea, which means that after the tea leaves are oxidized after harvesting, they undergo accelerated controlled fermentation. For accelerated fermentation, the wet layering process (Wo Dui 渥堆) is most often used, when biochemical reactions occur under the influence of microorganisms. In oxidation, biochemical reactions occur when interacting with atmospheric oxygen and typically last for several hours. The fermentation process can take several hours to several months, but can then continue without limitation for decades.

The Hei Cha tea category includes Liu Bao Cha from Guangxi, Tibetan bricks from Sichuan, Qing Zhuan Cha from Hubei, mature (Shu) Puer from Yunnan and several teas from Hunan. These are mainly the three brick teas Fu Zhuan Cha, Hei Zhuan Cha and Qian Liang Cha and the three loose teas Tian Jian, Gong Jian and Sheng Jian. The tea that unfortunately does not belong to this category is Liu An, because the modern processing process of this tea does not include layering under moisture, which is a condition for membership in this category. It wasn't always like that. Until a few decades ago, Liu An was produced similarly to Liu Bao or dark Pu Er. However, the exception is Luk On teas produced using old methods for the Hong Kong market, which Wo Dui has in the processing process.

Hei Cha teas go through a similar fermentation process to mature (dark) Puer. Basically, we can look at this tea as the ancestor of Puer tea. The name Hei Cha 黑茶 can be translated as "dark tea" and the history of this tea is more than 1000 years. Although processing methods have evolved and modernized over time, people throughout China still hold this tea in high regard as a regional specialty and a precious historical heritage. Specific processing techniques vary depending on the type of dark tea and the region of production. Originally, tea growers produced dark tea for export along the Silk Road to areas along the Chinese border. They always pressed the tea into cakes and bricks for easy transport and to keep it fresh.

Dark tea has a long history in China, with varieties produced in several provinces. The most important types include dark tea from Hunan, its most distinctive variant is Fuzhuan Cha. The origin of Fuzhuan Cha dark tea is closely related to the nomadic peoples of northern and western China, such as the Mongols, Tibetans and Uighurs. Their diet, rich in meat, milk and bread, lacks fiber and vitamins, making tea essential for digestion and nutritional balance. They consider tea indispensable, even more so than food for a short time.

In ancient and not-so-ancient times, people relied mainly on horses to wage war. They had a group of elite horse units that played an extremely important role in winning or losing the war. However, horse resources were unfortunately scarce in the Ming Dynasty. How to replenish horse resources therefore became an urgent problem for the Ming Dynasty government to solve. The pastoral area in the northwest happened to be rich in horses, and the two exchanges complemented each other. Therefore, the tea and horse trade appeared, a commercial activity in which everyone took what they needed. At first, individuals with one to several loaded animals appeared on the trail in the tea and horse trade, but gradually the number of horses and tea increased and the trail was occupied by long caravans. Imports were divided into private, commercial and government, and there was no shortage of smuggling.

Tea trade with China's border regions began during the Tang Dynasty (618-907 AD). During the Song Dynasty (960-1279 AD), the government established departments to manage the tea and horse markets, using tea as a strategic resource for negotiations with neighboring nomadic tribes. From central China, tea was one of the main trade items in exchange for horses from Mongolia. This tea and horse trading was called Cha Ma Hu Shi 茶馬互市 and was fully controlled by a special government ministry. Teas were called Guan Cha 官茶 or Fu Cha 府茶 according to the type of import because the tea trade was controlled by the government. At that time, the teas exported to these areas were green tea or similar types. It was a Hei Mao Cha type tea that serves as the starting material for pressing Fuzhuan Cha. Hunan was a major tea-producing region, where the method of packaging for transport by horse to distant markets was also developed.

The tea was carefully packed, loaded either on donkeys or horses, in many cases on the backs of poor porters such as Tibetan Sherpas, and traveled for several months. During the long journey, the tea was exposed to rain, humidity and high temperature. It was said that the tea was fermented unintentionally due to the high temperature and humidity. Interestingly, the flavor and taste of tea developed by this natural fermentation was well accepted by people. Due to the popularity of the taste and flavor of fermented tea, the Fuzhuan Cha process was invented in Shaanxi Province 陜西省 in the 1300s during the Ming Dynasty. The tea was first pressed and fermented with mold. Subsequently, Fuzhuan Cha and similar type of dark teas began to be produced not only in Shaanxi, but also in Hunan and Sichuan provinces. These teas were the predecessor of the so-called dark tea. Over time, several varieties of dark Hunan tea have emerged, including Hei Zhuan Cha, Qian Liang Cha, Fu Zhuan Cha, Tian Jian, Gong Jian, and Sheng Jian.

The tea and horse barter was monopolized by the government, which established the role of official government traders and punishments for smugglers. Despite all efforts, however, smuggling flourished as it always has and always will if governments want to regulate free trade. The entire business system of that time was not very different from today. There were central warehouses, distributors, inspectors and special laboratories for tea quality control. The price of both tea and horses varied from time to time, but tea was always much more expensive than horses.