For the average consumer, few have a comprehensive understanding of the entire pile fermentation process for ripe Tea, mainly because the stability of the microbial community in the fermentation workshop is so valuable that it is often treated as confidential by tea factories and strictly off-limits to visitors.
Secondly, even if one could enter for a tour, it would be difficult to conduct a follow-up study of each step, as the entire pile fermentation cycle lasts several days and includes different stages such as watering, turning piles, and ditching, making it a complex system.
Moreover, since the decisive role in pile fermentation is played by invisible microorganisms, it does not resemble modern manufacturing with standardized procedures and quantifiable metrics but is more like a technology guided by empiricism.
From controlling the temperature in the workshop to timing the turning of the piles, many steps in pile fermentation lack quantifiable standards, and the success or failure of each fermentation relies heavily on the experience and adaptability of the fermentation master.
Today, Lu Li will take fellow tea enthusiasts through the general process of pile fermentation.
Selecting the Fermentation Site
The site is crucial for pile fermentation. As water is applied during fermentation, it needs to retain some moisture. Once the temperature rises, excess moisture must be released promptly, requiring good absorbency and breathability of the ground.
Therefore, traditional fermentation workshops typically have brick or rough concrete floors, designed with a certain slope to allow excess water to drain away quickly and prevent the tea from rotting.
Some tea companies, out of food safety considerations, used to tile the fermentation pits, which affects drainage but, due to gaps between tiles, doesn't significantly impact overall fermentation.
In recent years, tea companies have adopted more hygienic methods such as elevated fermentation using Stainless steel panels with double layers or wooden barrels. Lu Li will delve into these further in upcoming articles on ripe tea.
After the floor is laid, it often has an odor and lacks dominant beneficial microorganisms, so it cannot be used immediately for fermentation. Instead, the land is nurtured to remove odors and cultivate a microbial community, ensuring the quality of the Fermented tea.
To nurture the land, broken tea leaves from previous batches are spread over the ground (do any tea enthusiasts know the purpose of this step?) to a height of about 1 cm, then thoroughly watered. Once dried, they are watered again to keep the ground moist.
When the concrete turns black and the tea residue loses its tea aroma, the nurturing is complete. However, newly constructed fermentation workshops are unlikely to produce high-quality ripe teas, so it is recommended to use lower-priced raw materials for the first few batches to minimize losses.
The same principle applies to premium ripe teas. If the raw materials are expensive, many tea companies rent fermentation workshops that have been used for many years to ensure stability in the microbial involvement.
For example, the famous 2004 Fojin Peacock Banzhang Ecological Tea, commonly referred to as “Fojin ABCD piles,” was fermented at Menghai Tea Factory and pressed at Xinghai Tea Factory, known for its rich flavor and full sweetness, and is highly sought after in the market.
After the reform of Menghai Tea Factory and the discontinuation of custom processing services, the He brothers borrowed the Xinghai Tea Factory's workshop to continue fermenting Banzhang ripe tea until the Fojin Brand was established and their own fermentation workshop built.
The following Xinghai 2006 Banzhang King Pu'er Ripe Tea, also fermented in the same workshop, boasts a smooth and delicate flavor with a hint of lotus fragrance, offering excellent value for money and is highly recommended.
Limited by the climate and environment of the workshop location, sometimes the first few batches do not achieve satisfactory results, which tests the judgment of the person in charge. They may need to re-nurture the land or find a new location.
Piling Tea and Watering
Once the site is constructed, production can begin. The first step is piling tea, which involves two critical technical points: the height of the tea pile and the amount of raw tea used.
Generally, the height of the tea pile ranges from 50 cm to 120 cm, with quantities varying from small piles of 100 kg to large piles of dozens of tons. There is a significant variation, partly due to different factory practices and partly due to the grade of raw tea for each batch.
Coarser tea generally forms taller piles because coarser leaves are looser, more breathable, and better at absorbing water, while finer tea is more compact and less breathable, a factor we will discuss further when talking about watering.
After piling the tea, it is time to water it. In early days, watering was relatively crude, involving someone holding a hose attached to a tap, spraying water onto the tea pile while another person monitored the water meter. When the desired amount was reached, the process was complete.
Nowadays, most workshops use sprayers to atomize the water, and a combination of watering and turning the piles is employed to ensure the tea is evenly moistened.
Water tends to flow downward, making the bottom of the pile too wet and prone to clumping, so if watering is done in the morning, the pile should be turned in the afternoon, and again the next morning, to distribute the moisture evenly.
The two most important parameters in the watering phase are the amount of water and the quality of the water, both of which depend on various factors including the moisture content of the fresh leaves, the grade of the leaves, and the season of production, testing the experience of the fermentation master.
The ratio of raw tea to water is usually around 3:10 to 5:10, with the moisture content of the raw tea ranging from 28% to 35%. Finer tea contains more moisture than coarser tea and requires less water; during the rainy season, with higher humidity, less water is added.
The amount of water determines the success of the fermentation, while the quality of the water influences the quality of the fermentation. Due to the benchmark effect of the “Menghai taste,” the industry mostly references the pH and microbial content of groundwater in the Menghai region when fermenting ripe tea.
Leaving aside the anecdotal “Menghai No. 1 Well,” the Menghai region has a superior ecological environment, and its groundwater is relatively pure, well-suited to the microorganisms in the fermentation workshop, making it an excellent source of water.
However, given its irreplicability, the industry seeks a more universal and cost-effective source of water, such as recent research showing that deionized water has good adaptability in ripe tea fermentation.
The deionized water mentioned here is not a health gimmick promoted by merchants but refers specifically to purified water that has had ionized impurities removed. Its characteristics include not being absorbed by large molecules within plant cells and affecting the physical properties of protoplasm.
This is because the water content in tea leaves is composed of free water and bound water. Deionized water can crystallize with free water and convert bound water into free water, maintaining “water activity.”
In the modern food industry, represented by alcohol production, deionized water has been widely utilized. Currently, the most advanced intelligent fermentation by Dayi uses deionized water, which will see increased application in future ripe tea fermentation.
Moisture Retention and Ventilation
After evenly watering the tea, the first round of fermentation can begin, but before covering the pile with a fermentation cloth, a major challenge must be addressed: balancing moisture retention and ventilation.
It is necessary to provide a stable environment for microbial activity, allowing the pile to warm up gently and maintain heat, while also ensuring adequate ventilation to support the normal transformation of the raw tea in the pile.
To solve this problem, the precise control of water volume is essential. As mentioned earlier, the ratio of raw tea to water is more precisely: 2.5 to 3:10 for high-grade raw materials and 3.5 to 5:10 for low-grade raw materials.
Secondly,