Dark tea’s ability to cut through rich, heavy food makes it a popular beverage in dim sum restaurants across China, Malaysia, and Singapore. Photo credit: Seth Griffin
Chinese hei cha or ‘dark tea,’ as the term is often translated into English, is one of the six major categories of tea produced in China, along with green, yellow, white, wulong, and red (black) teas. Unlike many other tea categories, which are meant to be consumed soon after production, dark teas undergo lengthy aging periods to develop deeper and more mellow flavors. Recent studies highlighting the health benefits of dark tea and its unique characteristics have propelled it onto the world stage. Now, consumers outside of China are finally discovering the bright side of dark tea.
Processing Methods
China is home to a wide variety of dark teas, many of which have been produced for centuries and are recognized as forms of national intangible cultural heritage. Its main distinguishing feature is an additional series of processing steps called ‘post-fermentation’ that utilize beneficial microorganisms to transform the flavors and aromas of the tea, causing it to darken. Tea industry experts remain hotly divided as to which climatic conditions of storage yield the best results, with some preferring the slower aging of a cool and dry environment while others swear by accelerated aging in a warmer, more humid storage.
Each tea has a unique recipe, but the general steps follow a similar course. Producers begin by rapidly heating the tea leaves to temperatures above 80° C (176° F) to interrupt the enzymatic activity and reduce moisture content through a process called ‘fixing’ or ‘kill green.’ Dark teas are typically fixed at lower temperatures than green teas, keeping some of the tea’s natural enzymes active during later processing.
Next, the leaves are shaped through rolling, further breaking down cell structures and coaxing internal compounds to the surface. After that, the processing veers in a unique direction. The leaves are heaped into piles and darken through further oxidation as microorganisms consume their contents and secrete aromatic compounds. These chemical changes generate heat, and the layers of the tea piles must be rotated so that the tea develops uniformly. The piles are kept within a temperature range of 40-65° C (104-149° F) so that overheating does not damage the tea leaves.
A large pile of Puer tea undergoing ripening in a factory in Yunnan, China. Photo credit: Seth Griffin
After piling, the tea leaves are rolled a second time and then dried. The final steps for dark tea involve more meticulous processes like sifting, blending, piling for lengthier periods of time, steaming, pressing into round or rectangular molds, and aging. Different dark tea recipes adjust the height and duration of piling, and sometimes use multiple stages of piling, re-rolling, drying, and rehydrating of the leaves before continuing with the finishing touches. The result typically yields deep-bodied, smooth, and earthy teas, with infusion colors ranging from vibrant gold to deep amber.
The History and Different Types of Dark Tea
Dark teas were among the historic ‘frontier trading teas’ (bian xiao cha 边销茶), which played a crucial role in commerce along China’s western and northern regions, popular in Tibet, Russia, and Mongolia. Their compact form made dark teas convenient to transport across vast distances.
Dark tea prepared with milk is a daily staple in rural Mongolia. Photo credit: Seth Griffin
While the ripe Puer tea of Yunnan province and Liu Bao tea of Guangxi province are the most widely known internationally, tea makers in China also produce several other types of dark tea that are famous domestically: Ya’an tea of Sichuan province, Anhua tea of Hunan province, and Xianyang tea of Shaanxi province, among others. These teas are crafted using different tea materials and techniques, creating unique characteristics that reflect each region. Quality grading standards and packaging methods also vary for each tea.
Ripe Puer
First emerging in Yunnan in 1973, Ripe Puer, also known as Puer shou cha, is the most recent addition to the dark tea lineup. This tea is crafted using sun-dried large-leaf assamica material sourced from Yunnan or neighboring Southeast Asian countries. It eclipses all other dark tea exports by a large margin and is sold in both loose and pressed forms, often as a 357-gram circular cake or 200-250g bricks.
Liu Bao
Named after its town of origin in Guangxi province, Liu Bao uses large leaf assamica material sourced from southwestern China and bordering countries. During the late Qing dynasty, it exploded in popularity as a way to cool off among Chinese migrant workers in Southeast Asia, where it is still served in dim sum restaurants today, often interchangeably with ripe Puer. Historically, it was sold pressed into large baskets. Once a highly affordable working-class tea, zealous collectors have caused the price of Liu Bao to skyrocket in the past decade, especially for older vintages, transforming it into a luxury item.
Ya’an Tea
Produced in Sichuan, Ya’an dark tea was historically traded with Tibetans. It is crafted from local small-leaf tea varietals using complex methods, including repeated steaming, rolling, piling, sun-drying, and sifting rounds. After final processing and pressing into molds, it is wrapped in paper and stored in a long, woven bamboo container.
Anhua and Xianyang Teas
Historically, tea produced in Anhua, Hunan, using Yuntaishan large leaf varietals was shipped to the bustling trade hub of Xianyang in Shaanxi province. There, it was re-processed, pressed into molds, and carefully aged to develop a beneficial yellow fungus known as “golden flowers” (Eurotium cristatum).
Lab analysis shows that this fungus contains 15 essential amino acids, greatly reduces the content of catechins in the tea while intensifying aromatic compounds, and inhibits the growth of other bacteria. After countless failed attempts to cultivate the fungus in Anhua, breakthroughs were finally made in 1953, and Xianyang’s role in the production process declined. The classic packaging for Anhua dark tea is a 35cm x 18cm x 3.5cm brick that weighs 2 kilograms.
Pressing teas into cakes or bricks made transportation and storage much easier and helped spread the popularity of dark teas across overland trade routes. Photo credit: Petr Sidorov
Market Size and Growth
Although dark tea production in China accounted for 423,000 tons or about 12% of China’s total tea production in 2023, the majority of that amount never reached the export market. According to the National Development and Reform Commission of China, in 2022, dark tea exports made up just 2,300 tons or 0.6% of China’s total 375,300 tons of tea exports, compared to 310,390 tons of green tea exports. Ripe Puer accounted for 1,900 tons or 82.6% of total dark tea exports in 2022.
According to Liu Zhonghua, botanical research director of Hunan Agriculture University, who spoke at the national forum on dark tea brand promotion in Hangzhou in November 2024, dark tea’s purported health benefits are helping spur domestic market growth. Liu cited studies suggesting dark teas help regulate metabolism, reduce blood lipids and lower blood sugar, promote weight loss, protect the liver from alcohol damage, and reduce blood uric acid levels. These touted benefits and the unique history of dark tea create a strong draw for customers.
Speaking at the same forum, Jiang Renhua of the Chinese Academy of Agricultural Sciences Tea Research Institute projected a bright future for dark tea in terms of domestic production. Jiang believes that the industry will continue to develop as Chinese consumers show a growing interest in health products. Measures such as improving product quality and branding, optimizing production, increasing consumer guidance, and standardizing market competition will facilitate the development of China’s dark tea industry, carrying it to even further frontiers.