In traditional Chinese tea production terminology, fermentation refers to microbial fermentation, also known as wet piling, and is typically performed after the tea leaves have been adequately dried and rolled. Through controlled microbial fermentation, the tea leaves also undergo oxidation until the desired flavors are achieved. This entire process results in a type of tea known as black tea, although it is commonly referred to as dark tea to distinguish it from English black tea.
History
Fermented tea leaves hold a significant historical importance among ethnic communities in Southwest China. These unprocessed teas have diverse origins and were designed to be cost-efficient. The Bulang and Dai peoples of Yunnan Province have been cultivating Pu'er tea on Jingmai Mountain since at least the 10th century. Traditionally, the tea trees would be planted in the lower area of the forests. A protective forest barrier would be established on the outskirts of these old tea forests to prevent the spread of pests and diseases, with cultivated land for crops and vegetables at lower elevations. Darkened tea, or black tea, remains the primary beverage for the ethnic groups in the southwestern regions. Up until the early 1990s, it was the third major category of tea produced in China, primarily for this specific market segment. Due to the cultural significance of Pu'er tea and its unique cultivation process, it was included in the UNESCO World Heritage List in 2023.
There was no standardized processing for the darkening of black tea until the postwar years in the 1950s. There was a sudden increase in demand in Hong Kong, possibly due to the influx of refugees from the mainland. In the 1970s, the improved process was brought back to Yunnan for further development, resulting in the various production styles now known as wòduī. This new process generated a final product in a matter of months, which many believed tasted similar to naturally aged teas of 10–15 years. It leads to a demand-driven surge in the production of black tea through the artificial ripening method.
In recent decades, demand has reverted, and it has become more common again for black tea, including Pu'er, to be sold as the raw product without the artificially accelerated fermentation process.
Shape
Pu'er tea cakes have a variety of shapes, including stacked melon pagodas, pillars, calabashes, yuanbao and small tea bricks (2–5 cm in width). The following shapes are commonly used to compress Pu’er.
- Cake:A flat, round, disc-shaped tea, varying in size from as small as 100g to as large as 5kg or more. A tea cake is usually 357g, 400g or 500g. Depending on the pressing method, the edge of the disk can be either rounded or perpendicular. It is also commonly referred to as Qīzí bǐngchá (literally "seven units cake tea") because usually seven tea cakes are packaged together for sale or transport.
- Nest:A convex knob-shaped tea, ranging in size from 3g to 3kg or more. 100g, 250g, and 500g are the most common ones. The term for tuocha is believed to have originated from the round, top-like shape of the pressed tea or from the old tea shipping and trading route of the Tuo River. In ancient times, tuocha cakes may have had holes punched through the center so they could be tied together on a rope for easy transport.
- Brick:It is a thick rectangular block of tea, typically available in sizes of 100g, 250g, 500g, and 1000g. Bricks are convenient for transportation along the ancient tea route by horse caravans.
- Dragon Pearl:It’s a small ball-shaped or rolled tea, designed for a single serving. Typically, these dragon pearls contain 5 to 10 grams of compressed tea This practice is also common among Yunnan black tea and scented green teas.
Production
Two main styles of Pu'er production are in existence: a traditional, lengthy process known as shēng (raw) Pu'er and a modern, accelerated process known as shóu (ripe) Pu'er. Pu'er typically begins with a raw product called rough tea and can be sold as raw tea or pressed into various shapes. Both types undergo a complex process of gradual fermentation and maturation over time. The wòduī fermentation process, developed in 1973 by the Kunming Tea Factory, introduced a new type of Pu'er tea. This process involves accelerated fermentation into ripe tea, which can then be stored loose or pressed into various shapes. The legitimacy of ripe tea is a subject of debate among some traditionalists when compared to traditionally longer-aged teas, such as raw tea.
- Raw Pu'er:Over time, raw Pu'er undergoes a gradual oxidation process and is influenced by microbial factors, resulting in an earthy flavor. Unlike green, oolong, or black tea, this oxidation is not facilitated by the plant's own enzymes, but rather by fungal, bacterial, or autooxidation influences. The aging process can significantly alter the flavors of Pu'er, producing a brew with a robust earthy yet clean and smooth taste, reminiscent of rich garden soil or an autumn leaf pile, sometimes with roasted or sweet undertones. Well-aged high-quality Pu'er gains value over time due to its ability to age without losing quality, similar to aged roasted oolong.
Raw Pu'er can undergo "wet storage" and "dry storage", with teas undergoing dry storage aging more slowly but thought to exhibit more complexity. Dry storage entails maintaining the tea at a comfortable temperature and humidity, allowing it to age gradually. Wet or humid storage involves storing Pu'er tea in naturally humid environments such as Hong Kong, Guangzhou, and Taiwan. Another crucial step involves misting the tea with water and letting it dry in a humid environment. This process accelerates oxidation and microbial transformation, simulating natural dry storage aged Pu'er but without developing the complexities of slow aging.
Pu'er tea stored in different environments can experience diverse aging processes due to variations in ambient humidity, temperature and odors. For example, Pu'er stored in Yunnan, Guangzhou and Hong Kong ages differently. The extended aging period can lead to varied aging conditions and significantly change the flavor. High temperatures, direct sunlight exposure, strong airflow, liquid water, or unpleasant odors can have adverse effects on raw Pu'er.
While controlled airflow is essential for aging raw Pu'er, most collectors and connoisseurs concur that raw Pu'er tea cakes older than 30 years should not be further exposed to open air, as it may lead to flavor loss or a decline in mouthfeel. Instead, the tea should be preserved by wrapping or sealing it hermetically in plastic or ideally glass.
- Ripe Pu'er:The discussion regarding the aging of ripened Pu'er mostly revolves around whether the process will alter the flavor of the tea since the ripening process was designed to mimic aged raw Pu'er. It is generally recommended to age ripened Pu'er in order to eliminate the unpleasant musty flavors and odors resulting from maocha fermentation. However, some collectors argue that aging ripened Pu'er beyond 10 to 15 years is illogical and may cause the loss of the desirable flavors. On the other hand, there are those who assert that aging does enhance the nuances of ripened Pu'er, as evidenced by side-by-side taste comparisons of Pu'er of different ages. While aging the tea increases its value, it may not always be profitable.
Benefits
Pu'er tea has surged in popularity owing to its myriad health benefits. This fermented tea is abundant in polyphenols and contributes to digestion. In Chinese tradition, Pu’er has been renowned for centuries for its ability to combat greasiness and facilitate digestion following heavy meals. Research validates its efficacy in breaking down fats and enhancing the balance of beneficial bacteria in the digestive tract.
Moreover, it bolsters gut health through its diverse array of bacteria, shields the nervous system, and fosters brain health. The caffeine in Pu'er tea can elevate energy levels, sharpen focus, and aid in weight management. For weight loss, it is recommended to consume a cup of Pu'er tea one hour after a meal to help reduce excess grease and aid in the digestion of hard-to-digest fats.
What’s more, Pu’er tea can helps cleanse toxins and free radicals since it contains antioxidants which prevent damage caused by free radicals. It also contains statins that can lower cholesterol, thereby improving heart health.