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# The Production of Pu-erh Tea
- URL: https://caotea.com/the-production-of-pu-erh-tea/
- Published: 2026-09-21T21:34:21.000Z
- Updated: 2026-09-22T04:48:16.000Z
- Description: Sun-drying reveals the true magic of Pu-erh tea: intense plateau sunlight triggers pheophytinization and photo-oxidation. This eliminates harsh grassiness, locks in a distinct floral 'sun-dried aroma,' and lays the chemical foundation for the dark, lustrous color of richly aged tea.
- Author: CAOTEA Lab

## I. Introduction:

1. The production process used by large-scale tea enterprises differs from the one introduced in this article. The production of Pu-erh tea on the scale of hundreds of tons relies on machinery and electrical power. However, because the biochemical characteristics remain the same, the overall process is largely identical to what is described here and can equally serve as a reference.
2. Due to delays in the revision and formulation of the National Standard GB/T 22111, this article introduces the production of Pu-erh tea based on field investigations and industry consensus. Precisely because of these non-unified standards, a small number of technical terms vary in nomenclature across different regions.
3. **Processing workflow of raw Pu-erh tea (Sheng Cha):**

> "Plucking – Spreading/Withering – Fixation (Sha Qing) – Rolling – Sun-drying (Shai Qing) – Sorting Yellow Flakes (Huang Pian) – Steaming and Pressing – Drying – Packaging"

It should be clarified that, from the perspective of its inherent properties, tea leaves that have undergone the "sun-drying" step can already be referred to as "raw Mao Cha" (crude tea). The subsequent steps are merely intended to optimize flavor, storage, and preservation. Therefore, high-grade ancient tree tea is generally sold in the form of "loose tea" (San Cha), because the "steaming and pressing" process subjects the tea leaves to a secondary heating and humidification, which slightly compromises the inherent quality of the tea. Prior to the birth of the ripe tea (Shu Cha) processing technique in 1973, Yunnan large-leaf varietal tea was not divided into "raw" and "ripe." Historically, it had various names: Pu tea, Dian Qing, Yunnan tea, Pu-erh tea... In terms of processing steps and nature, it was largely similar to traditional Chinese green tea processing (the differences will be detailed below).

1. **Processing workflow of ripe Pu-erh tea (Shu Cha):**

> "Plucking – Spreading/Withering – Fixation (Sha Qing) – Rolling – Sun-drying (Shai Qing) – Sorting Yellow Flakes (Huang Pian) – Water Spraying (Chao Shui) – Wet Piling (Wo Dui) – De-lumping and Grading – Steaming and Pressing – Drying – Packaging" 

Similarly, from the perspective of inherent properties, the tea leaves can already be called ripe Pu-erh tea once they have undergone wet-piling fermentation.

1. **The Concepts of Primary Processing (Chu Zhi) and Refined Processing (Jing Zhi):**

**Primary Processing (Chu Zhi):** "Chu Zhi" means preliminary production. Steps such as plucking, spreading, fixation, rolling, and sun-drying are mostly completed by tea farmers. The resulting product is called "Mao Cha" (crude raw material tea), which is classified as a primary agricultural product. Temperatures in Yunnan's tea-producing regions are generally high in March and April. Fresh leaves newly plucked from tea trees will rapidly oxidize and deteriorate if not processed immediately. Coupled with the inconvenient transportation in high-altitude mountainous areas, fresh leaves are not directly transported to distant factories for processing. In order to exercise stricter control over the primary processing workflow, large tea enterprises generally invest in building "Primary Processing Stations" (Chu Zhi Suo) on the tea mountains, which process fresh leaves according to company-specified standards.

**Refined Processing (Jing Zhi):** "Jing Zhi" means refined/fine production. Within the legal framework of food processing in China, pre-packaged food can only be marketed and sold after passing a processing procedure that complies with national standard certifications. Generally, processing plants holding an SC (Production License) certification purchase Mao Cha from tea farmers and then carry out deep processing and packaging in subsequent steps. Processing Mao Cha by tea farmers without corporate licensing falls under "homemade food," which cannot be sold on the open market, and consumer food safety cannot be guaranteed.

![](https://caotea.com/content/images/2026/09/111.jpg)

## II. The Tea Farmers' Primary Processing of Sun-Dried Green Mao Cha (Shaiqing Mao Cha):

> *Plucking (Cai Zhai) – Spreading (Tan Liang) – Fixation (Sha Qing) – Rolling (Rou Nian) – Sun-drying (Shai Qing) – Sorting Yellow Flakes (Tiao Huang Pian)*

In Xishuangbanna, the place of origin of Pu-erh tea, tea farmers living in the mountains still cultivate tea trees, pluck tea leaves, and produce sun-dried Mao Cha in household workshops.

![](https://caotea.com/content/images/2026/09/222.jpg)

**1\. Plucking (Cai Zhai)** 

Plucking refers to harvesting the tea leaves. The harvesting period for spring tea runs from early March to April, while the harvesting period for autumn tea is in October.

![](https://caotea.com/content/images/2026/09/333-1.jpg)

Ancient tea trees growing in forest tea gardens / Terraced young tea gardens planted in ridges

Both types are primarily plucked by hand. When the tea plucking season arrives, the entire family, young and old, is mobilized to participate in harvesting.

![](https://caotea.com/content/images/2026/09/5555.jpg)

The freshly picked buds and leaves are referred to by locals as "fresh leaves" (Xian Ye). 

During the process from plucking to bringing them home, tea polyphenol oxidase becomes active due to the warm and humid climate, triggering enzymatic reactions (similar to the browning of a sliced apple). To inhibit this change, the tea leaves are spread out on bamboo mats to ventilate and dissipate heat.

**2\. Spreading (Tan Liang)**

![](https://caotea.com/content/images/2026/09/666-1.jpg)

The leaves brought home are spread out on winnowing baskets or bamboo mats and placed in a cool, shaded area.

Moisture evaporates for 1 to 2 hours (depending on the ambient temperature of different regions; in high-altitude areas of Lincang where temperatures are lower, this process lasts longer) until the tea leaves wither and become soft. This process is locally termed "Zou Shui" (water-running/moisture dissipation). This is an exceptionally critical phase in tea processing, relying entirely on experience rather than instruments to gauge the degree of moisture loss. Different types of tea require different degrees of moisture dissipation; for instance, in black tea production, because fixation is not performed, the withering (Wei Diao) time can last as long as 24 hours. Variations in the moisture content of fresh leaves dictate temperature control in the subsequent fixation stage: high moisture content leads to a slow rise in leaf temperature, making the leaves prone to oxidation and reddening; low moisture content easily leads to charring and uneven fixation.

**3\. Fixation (Sha Qing)** 

Fixation is the process of using heat to halt further changes in the internal components of the tea leaves (deactivating enzyme activity). Typically, leaves are plucked in the morning and fixed in the evening, which prevents the fresh leaves from reddening and oxidizing. After fixation, they undergo rolling, de-lumping to dissipate residual heat, and are sun-dried starting the next morning.

![](https://caotea.com/content/images/2026/09/7777.jpg)

Fixation is an experiential task requiring "rapid judgment within a short window of time." Compared to other tea-making steps, the fixation process is harder to control and has a lower margin for error. Although the entire tea processing mechanism has been deciphered by scientific principles, variations in climate, fresh leaf conditions, and temperatures require real-time heat adjustments according to the specific condition of the leaves; otherwise, the quality of the Mao Cha will be severely compromised. 

Due to strong phenotypic plasticity in tea trees and secondary metabolic regulation, combined with Yunnan's intricate geographical factors, the finished tea produced across each mountain, each tea plot, and even individual tea trees exhibits significant differences in taste. For hardcore tea connoisseurs who pursue these nuances, in order to preserve these differences and unique profiles, they custom-order processing based on specific plots or individual trees. Consequently, ancient tree tea is usually pan-fried manually in iron woks, while leaves from terraced plantations and young tea gardens are predominantly processed using rotary drum fixation machines. 

Today, the fuel used for fixation is still predominantly firewood, but the proportion of electric heating equipment is increasing year by year. China is the world's largest power-generating nation, featuring a stable electrical supply without shortages and low electricity rates. Although electric fixation machines offer higher controllability and output, they still require substantial human experience to assess the appropriate degree of fixation.

**4\. Rolling (Rou Nian)**

 Rolling refers to the process of forcefully rubbing and kneading the tea leaves to rupture their cell walls, causing the intracellular contents within the vacuoles to leach out and shaping the leaves into tightly twisted, rope-like strips. After fixation, once residual heat has completely dissipated, rolling is performed by hand. In recent years, the number of tea farmers using small-scale rolling machines has also been steadily increasing.

![](https://caotea.com/content/images/2026/09/8888-2.jpg)

Furthermore, adequately rolled tea leaves form a shape that locks in cellular substances, rendering the tea more durable across multiple infusions. After rolling is complete, the tea leaves are spread out on bamboo mats, awaiting the next day's sunlight for sun-drying.

**5\. Sun-Drying (Shai Qing)** 

The processing of Chinese tea is inextricably linked with "Qing" (green leaf handling); different processing temperatures dictate the resulting tea category. Aside from sun-drying (Shai Qing), there are also pan-drying (Chao Qing), baking/oven-drying (Hong Qing), and others. 

Resourceful Yunnan tea farmers made full use of the natural conditions on the Yunnan plateau—abundant sunshine duration, intense ultraviolet rays, and high temperatures—to carry out "sun-drying" on tea leaves after fixation. In contrast, during the budding season in regions like Jiangsu and Zhejiang, the climate is humid and rainy, prompting the widespread adoption of firewood baking/drying methods. The chemical process of sun-drying fortuitously matches the compositional traits of Yunnan large-leaf varietals, which possess higher levels of tea polyphenols and caffeine than medium-to-small-leaf varietals—a truly wondrous coincidence.

The core principles of sun-drying are: Pheophytinization and Photo-oxidation, while simultaneously reducing the moisture content to 9% or even lower, keeping the tea dry and eliminating the environment required for rapid fermentation.

![](https://caotea.com/content/images/2026/09/9999.jpg)

Following fixation and rolling, cellular disruption releases organic acids from the vacuoles, bringing them into contact with chlorophyll. Under a slightly acidic environment and the thermal action of solar radiation, pheophytin is formed. This is the primary chemical reason why sun-dried Mao Cha exhibits a dry-leaf color of dark green, deep green, or even oily blackish-brown. In contrast, the operating temperature for baked green tea (Hong Qing Green Tea) reaches over 80°C for a shorter duration; the rapid thermal deactivation yields less pheophytin, preserving an emerald green appearance.

After sun-drying, the residual pheophytin and polyphenols continue to complex with tea polyphenol oxidation products during prolonged aging, shifting toward brownish-red and deep red, which becomes an essential foundation for the reddish-brown soup color and sleek dark appearance of aged raw tea. Simultaneously, under intense light radiation and oxygen, chlorophyll is converted into highly active superoxide free radicals and undergoes further oxidative degradation, leading to a decline in total pigment content and reducing the original vivid green density of the tea liquor. 

Because sun-dried tea undergoes a prolonged dehydration period, hydrolyzed hydrophilic pigments dissolve out, resulting in a liquor that is bright yellowish-green for young teas of the current harvest, whereas baked green tea yields a pale, clear green liquor. During photo-degradation, chlorophyll generates volatile compounds characterized by floral, fruity, and dried-hay aromas, weakening grassy notes and imparting the signature "sun-dried aroma".

![](https://caotea.com/content/images/2026/09/qqqq.jpg)

In the event of overcast or rainy days, drying is carried out using the equipment shown in the illustration. Under such circumstances, the tea's flavor profile will experience a slight decline.

**6\. Sorting Yellow Flakes (Tiao Huang Pian)** 

During the plucking of tender shoots, slightly older leaves are inevitably harvested alongside them. The essential difference between old leaves and tender leaves lies in the fact that old leaves are more resistant to light and acid, and their yellow lutein and carotenoids have accumulated in large quantities and exist in a stable state. Chlorophyll, by contrast, is extremely fragile; once chlorophyll is degraded, the underlying yellow tones of lutein and carotene are fully exposed. This is the origin of "Huang Pian" (yellow flakes). 

Compared to tender buds, yellow flakes contain lower concentrations of catechins, caffeine, and amino acids, but higher levels of polysaccharides, pectin, and lignin. Consequently, yellow flakes have weaker astringency, bitterness, and salivation-inducing intensity, as well as lower freshness and aroma; conversely, the tea liquor exhibits higher viscosity and sweetness. High-quality ancient tree yellow flakes can even present sophisticated woody aromas, offering exceptional value for tea drinkers with low caffeine tolerance.

![](https://caotea.com/content/images/2026/09/wwww.jpg)

There are two methods for sorting yellow flakes: one is spreading the sun-dried Mao Cha in a winnowing basket and tossing it up and down so that the yellow flakes gather along the rim; the other is hand-picking them leaf by leaf.

Once the sorting of yellow flakes is complete, the production of sun-dried Mao Cha is finished. It is packed into large sacks of 15 kg to 20 kg each and stored in the homes of tea farmers, awaiting sale.

## III. The Tea Factory's Refined Processing of Finished Products:

Compressing sun-dried Mao Cha into shaped forms or fermenting it into ripe tea is the work of tea factories.

![](https://caotea.com/content/images/2026/09/eeee.jpg)

Tea factories are mostly concentrated in small towns or county seats near the tea mountains.

![](https://caotea.com/content/images/2026/09/rrrr.jpg)

They range from small workshops staffed by only a few individuals to large-scale modern tea factories employing hundreds of workers.

> Refined processing workflow for raw tea: "Weighing – Batch Blending (Yun Dui) – Steaming and Pressing – Drying – Packaging"

> Refined processing workflow for ripe tea: "Weighing – Batch Blending (Yun Dui) – Water Spraying (Chao Shui) – Wet Piling (Wo Dui) – De-lumping and Grading – Steaming and Pressing – Drying – Packaging"

**1\. Weighing** 

Once sun-dried Mao Cha transported from tea farmers arrives at the tea factory, it is weighed immediately to calculate the time and cost required for processing.

![](https://caotea.com/content/images/2026/09/tttt.jpg)

If not processed right away, the sun-dried Mao Cha is stored directly in warehouses. Quality-conscious manufacturers will conduct foreign-matter sorting, typically employing optical laser sorting machines to eliminate foreign materials from the tea (common contaminants include hair, bamboo broom bristles, and woven polypropylene bag fibers).

**2\. Wet Piling (Wo Dui):**

Producing ripe tea involves a "wet piling" stage where tea leaves are heaped for fermentation. This requires a fermentation workshop capable of processing 5 to 20 tons of tea at a time, clean water and air essential for fermentation, and warm climatic conditions. Fermentation factories for Yunnan ripe tea are primarily concentrated in Menghai.

![](https://caotea.com/content/images/2026/09/yyyy.jpg)

Producing ripe tea involves a "wet piling" stage where tea leaves are heaped for fermentation.

The tea leaves are piled to a height of approximately 70 cm, sprayed with water, and covered with white thermal and moisture-retaining cloths. The walls and floors of the fermentation workshop harbor beneficial yeasts and *Aspergillus* molds known as "warehouse flora" (Cang Jiao), microorganisms that have evolved over years and are exceptionally conducive to fermentation. Microbial colonies directly influence the taste and aroma of ripe tea; therefore, for many prominent brand-name factories, their specific fermentation flora is strictly guarded as a trade secret.

Once fermentation initiates, the tea leaves generate heat spontaneously, with core internal temperatures reaching above 50°C. To ensure uniform fermentation, the piles must be turned periodically, and compacted clumps must be broken apart to prevent "core burn" (overheating of the interior). Appropriate amounts of water are replenished during each turning. The wet-piling fermentation process lasts approximately 1 to 2 months.

The tea leaves turn tea-brown, until moisture naturally evaporates and fermentation halts. Afterward, the tea is dried directly in the shade.

Following wet-piling fermentation, the tea leaves adhere and clump together, necessitating mechanical sifting. 

![](https://caotea.com/content/images/2026/09/uuu.jpg)

Leaves with high pectin adhesion that are difficult to break apart are known as "Cha Tou" (tea nuggets/heads), usually forming hard lumps 1 to 3 cm in diameter. In the history of Pu-erh tea fermentation, these were categorized as scrap material and discarded for a long time. 

Tea used for blending is sifted based on leaf appearance and internal content, graded into tiers: Premium Grade (Gong Ting / Palace Grade), Grade 1, Grade 3, Grade 5, Grade 7, Grade 9, and so forth.

**3\. Steaming, Pressing, and Packaging:**

The thoroughly dried tea leaves are steamed to soften them. They are then pressed and shaped using cloth bags and shaping molds into "compressed tea," and finally dried once more.

In earlier days, manufacturers operated boiler rooms fueled by honeycomb coal briquettes, conveying hot steam across the factory premises via iron pipes; today, electric heating is predominantly used.

![](https://caotea.com/content/images/2026/09/iiii.jpg)

The compression processing line operates through the division of labor among small teams. Workers sequentially perform tea weighing, steam-softening, cloth-bag wrapping and kneading, mold compression, and neat placement onto drying racks. 

Large-leaf varietal tea possesses thick, long strands. Without steaming and pressing, it occupies substantial space (standard Mao Cha takes up approximately 10 liters / 2.6 gallons of volume), and its large surface area exposed to air makes it more prone to absorbing off-odors and undergoing accelerated transformation. Historically common compressed forms include: round cakes (357 g, 200 g, 100 g), mushroom-shaped Tuocha (100 g–500 g), and Jin Gua (golden melon) tea. Following the introduction of modern machinery, factories need only switch out CNC-machined metal molds to adjust production to different compressed shapes and freely customizable weights.

![](https://caotea.com/content/images/2026/09/oooo.jpg)

After residual heat dissipates on the drying racks, the cloth bags are untied, and the tea is moved into drying rooms.

![](https://caotea.com/content/images/2026/09/pppp.jpg)

Once dried, the tea is placed again in a cool area to dissipate residual heat, wrapped in wrapper paper and bamboo tongs (sheaths), and finally boxed for shipment at standard specifications of 42 cakes per carton (for 357 g round tea cakes).

## IV. Stone Mold Pressing of Traditional Cake Tea:

This represents the most traditional crafting technique for Pu-erh tea. Pressing tea into disc-shaped cakes is estimated to have originated around 1700 during the Ming/Qing era in the Yiwu region. Yiwu still retains small workshops where several craftsmen operate entirely by hand. For roughly 50 years starting around 1950, workshop-based tea making was temporarily interrupted, but it has experienced a revival in recent years. Facilities in manual workshops are rudimentary, consisting merely of tea steamers resembling inverted iron woks, stone molds, and drying racks.

![](https://caotea.com/content/images/2026/09/ssss.jpg)

Stone Mold Pressing of Traditional Cake Tea

Mao Cha is weighed, poured into a steaming cylinder, softened with steam, transferred into a cloth bag, and pressed beneath a stone mold. A worker stands atop the stone mold, rocking their body weight to stomp and compress the tea into a firm, set shape. It is kept indoors to air-dry overnight until the following day, exposed to direct sunlight for approximately 3 hours starting in the early morning, brought back inside to dissipate residual heat, and finally packaged—marking the completion of the process.

![](https://caotea.com/content/images/2026/09/dddd.jpg)