Tea Education

Pu’er Tea: The Tea of Teas

Pu’er Tea: The Tea of Teas

Collected by connoisseurs, Pu’er Tea is geographically indicated and exclusively produced in Yunnan and the original birthplace of human’s interaction and enjoyment of tea consumption. Pu’er Tea is a special type of tea that is usually sold in compressed cakes or bricks that are cellared, aged and appreciated for its vintage and unique attributes that are similar to fine wine. All Pu’er is made with Sun-dried green tea that is slightly oxidized and fermented according to recipes that shape the incomparable and collectible characteristics of Pu’er tea. 

Date:

December 20, 2023

Author:

Joshua Kaiser

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Compressed tea cakes are a gateway to the past, and a reminder of the force of nature. The force begins in the trees. The oldest living tea trees in the world are found in Yunnan and the neighboring mountains reaching across northern Burma, Thailand, Laos and Vietnam, a region famous for its biodiversity of flora and fauna.

Some tea gardens are literally groves of tea trees deep in the forest, hundreds of years old, grown from heirloom seeds, with roots running deep, reaching over 2m-10m in height with branches covered in symbiotic lichen, moss and fungi. Like old vine wines, these tea trees produce leaves with unique phytonutrients and secondary metabolites leading to powerful 茶气 Cha Qi or “tea energy” in the brewed cup. Once harvested, the tea is wilted, roasted, kneaded, sun-dried and finally compressed according to an ancient tradition that made the tea fit for long treks across overland trade routes. These tea cakes and bricks are considered “living” teas that transform over time and are often intentionally stored and aged as collectable vintages. Tea cakes are a tea connoisseur’s dream.

There are two general categories of Pu’er Tea. Sheng Pu’er (Raw Green Pu’er) and Shu Pu’er (Ripe Fermented Pu’er). Both categories of Pu’er are produced using a type of Sun-dried green tea known as Shai Qing Maocha which is harvested, withered, pan-fried, kneaded/rolled, and laid out on bamboo mats under the direct sunlight.

This natural drying method, that uses the Sun’s energy, predates the modern and more widespread practice of oven drying tea. Using the sunlight results in slow rate of natural drying and creates a unique partially oxidized and fermented profile that only the Sun’s natural UV can produce. Unlike, oven baking or high fire roasting, which totally kills the active enzymes, and stops oxidation of green tea, Sun-drying does not totally kill or de-activate the enzymes, so the Sun-dried green tea still has partially active enzymes, although the tea is dried. The slow drying and partial deactivation of tea enzymes create the unique character of Pu’er tea which is cherished as a so called “living tea” and one that develops overtime. This meaning of development is that the tea will continue to gradually oxidize via enzymatic oxidation and normal non-enzymatic oxidation while the tea is stored, altered in character by fermentation through the activity of bacteria and fungus.

SHENG (Raw Pu’er) 
Sheng Pu’er is made from tea leaves that were processed similar to green tea: picked, wilted and withered, pan-roasted, kneaded and rolled before being laid out onto bamboo mats to be sun-dried. This sun-dried variation of green tea is then steamed so that it becomes soft and pliable. It is then compressed into forms of cakes, bricks, bird’s nest/ball shapes, mushrooms, pumpkins, melons, coins or a multitude of other forms and various gram weights.

The steamed and compressed cake tea is then slowly dried in a hot and dry sauna-type room which is carefully set at a special temperature and relative humidity that does not totally de-enzyme the tea. The steaming and careful re-drying process serves to preserve the gradual enzymatic activity within the final compressed Sheng Pu’er so that it can be stored and aged well, if that is what the buyer intends to do with the tea.

Most Sheng Pu’er is stored and aged for several years before consumption but some people have an affinity to the freshness, unique aromas and dynamic energy of fresh or young Sheng Pu’er. We can consider the aging process very much like fresh or young wine being cellared and aged to transform the sharp tannin. Because raw pu'er doesn’t go through the piling process of Shu Pu’er (Ripe Fermented Pu’er) it retains a fresh and original scent, as well as a bit of brisk astringency, followed by a sweet aftertaste (Hui Gan effect). Multi-floral aromatics and degrees of bitter-sweet and sweetness, and with refreshing and long lasting salivation effects, can be found along the way of a great vintage’s maturation. You can taste the terroir and distinctive vintage characteristics in Sheng Pu’er. 

SHU (Ripe, Fermented Pu'er) Shu Pu’er teas undergo a controlled wet pile fermentation process in which naturally occurring bacteria interact and consume the tea polyphenols in tea. The clear and off-yellowish Sun-dried green tea slowly ferments and transforms into a reddish-brownish colored tea over the course of about 65-85 days, and sometimes longer, based on the desired depth and style of fermentation the tea maker intends. The pile-fermentation processing of sun-dried green tea results in a dark Pu’er tea that during a simultaneous biochemical process described as natural bacteriological fermentation and polyphenol oxidase enzymatic oxidization. A complex of patina of fungi and bacteria (from the Aspergillus family) develops in the pile of sun-dried green tea.

There are not additives in the traditionally made Pu’er teas. Only the influence of heat and moisture enhance the fermentation process, which is very similar to something between a compost pile and dry kombucha. Basically the natural bacteria feed and eat the high catechin and polyphenols in the varieties of Pu’er maocha (a term for loose or unfinished tea). The biological reaction by-products are gallic acids, amino acids and deep reddish and brownish complex polyphenols (thearubigin and theabrownin). As the bacteria feeds on the polyphenols, the color of the tea leaves become darker and the astringency and sharpness of the fresh green tea is transformed into sweet, fermented, earthy and cocoa-like flavors. The raw material maocha source, the elevation and overall temperature and humidity of the fermentation factory and the skills of the fermentation master all shape the quality and taste of Shu Pu’er.
The basic process of ripe fermented Shu Pu’er tea is called ‘wet piling’ (渥堆 – Wo Dui). The wet piling fermentation process is as follows: The sun-dried green tea is piled up in a hot and somewhat humid condition. The tea is wetted with fresh water from time to time.
The inner pile heat is monitored and when the heat is accumulated, the pile is scattered, turned over and re-piled so the heat is removed and the pile is ventilated to increase oxygen and flow. Sometimes the pile is covered with cloth to accumulate heat and moisture and sometimes the pile is left uncovered and adjusted to different heights and thicknesses, depending on the stage of the fermentation and desired result. When the fermentation reaches the desired level, the tea is slowly dried and stirred in the Sun, or more commonly, it is slowly dried in a dry and hot sauna-like chamber designed for Pu’er processing.