The Rolling of Puer Tea is the first process after the tea has been subjected to initial heat treatment (withering). Traditionally, the method involves transferring the withered tea from the wok onto bamboo mats, wide wooden boards, or clean cement floors, where the tea is manually “rolled” and “twisted” by hand. This action is somewhat similar to kneading flour. So, what is the purpose of rolling Puer tea?
Puer Tea Rolling Methods
1. Manual Rolling
The manual rolling of Puer tea typically requires two rounds of rolling. The first round occurs after the tea has been withered and laid out to cool; it is rolled until the leaves are mostly in strip form and tea juice begins to seep out. The leaves are then left to dry until the next morning before undergoing a second round of rolling to ensure that even the coarser and older stems and leaves are tightly formed into strips. A special bamboo-made rolling mat is used for this process. The rolling technique requires circular, complete, and coordinated movements that are both firm and gentle, ensuring that the tea leaves are evenly pressured and conducive to forming strips.
The duration and strength of the rolling are closely related to the quality of the product. If the rolling time is too short and the force too strong, it can cause the stems and leaves to separate and break rather than forming strips. On the other hand, if the rolling is too gentle, the cell damage rate will be insufficient, making it difficult to maintain the integrity of the strips. When rolling tender leaves, the force should not be too strong, and the duration can be extended to ensure the leaves do not break and still form strips while also revealing fine downy hairs. Conversely, when rolling coarser and older leaves, more force is required to achieve the desired strip formation. Properly rolled leaves have a strip formation rate of over 85% and a cell damage rate of over 45%, with tea juice adhering to the Leaf surface, giving a smooth and sticky feeling when touched. After rolling, the leaves must be immediately separated and dried to prevent yellowing. Manual rolling is labor-intensive and produces inconsistent results, so it is not commonly used in mass production. Instead, rolling machines are widely used.
2. Machine Rolling
Using rolling machines is the most common method of rolling in Puer tea production areas today. The cell damage rate during rolling is between 45-60%. The degree of rolling depends on the tenderness of the Raw material and the desired outcome of the finished tea, which is controlled through pressure and rolling time. The amount of tea put into the rolling machine depends on the diameter of the rolling drum. If too little tea is added, the pressure will not effectively compact the strips; if too much tea is added, the pressure will be uneven, making it difficult for the leaves to roll properly initially, resulting in a loose and broken appearance. An appropriate amount of tea should naturally fill the rolling drum.
“Pressure” refers to increasing the rolling force. The pressure applied during rolling and the duration of pressure application significantly affect the tightness and fragmentation of the tea strips. The degree of rolling also greatly influences the cell damage rate and the color, aroma, and taste of the Puer tea. The principle of pressure application during the entire rolling process should be “light, heavy, light.” The rolling time should be determined based on three principles: the tenderness of the leaves being rolled, the size of the rolling drum, and the tightness of the strips formed as observed on the rolling plate. Experienced rolling technicians adjust the amount of tea, rolling pressure, and rolling time according to the tenderness of the leaves and the machine's load to ensure proper rolling and maintain the quality of the tea.
Functions of Rolling
Moderate rolling serves two purposes: first, it shapes the tea leaves, and second, it lays the foundation for the post-fermentation transformation of raw Puer tea. Rolling breaks the cell walls of the tea leaves, allowing polyphenols, catechins, and other active ingredients in the tea to polymerize, thereby enabling the tea to undergo post-fermentation over time.
If the rolling is too light, the resulting raw tea becomes “puffed,” with a light flavor. If the rolling is too heavy, the raw tea becomes “tightly rolled,” with a turbid infusion, high bitterness and astringency, and an increased likelihood of developing off-flavors during storage.
Purpose of Puer Tea Rolling:
1. In terms of appearance: Rolling makes the tea leaves curled and soft after withering, giving the final tea a beautiful strip shape.
2. For subsequent oxidation: Rolling damages the cells of the tea leaves, releasing tea juice and allowing the polyphenols, polysaccharides, caffeine, and other chemical components in the tea to come into contact with oxygen in the air, initiating oxidation reactions.
Thus, the rolling process of Puer tea not only affects the appearance of the strips but also plays a crucial role in the subsequent oxidation processes.