Advanced Processing Technologies of Tea

Natural withering: This is the initial step in tea processing for many types of tea. During natural withering, fresh tea leaves are spread out thinly in a well - ventilated and shaded place. The leaves lose water gradually, and their internal chemical components begin to change. For example, in the processing of white tea, natural withering is a crucial step. The slow water - loss process allows the tea leaves to develop a unique fresh and mellow flavor.

Artificial withering: In some cases, due to weather conditions or production efficiency requirements, artificial withering is used. This can be achieved through the use of air - conditioners or withering machines to control the temperature, humidity, and ventilation. Artificial withering can shorten the withering time while still maintaining the quality of the tea leaves to a certain extent.

Traditional hand - rolling: In traditional tea - making, hand - rolling is a labor - intensive but highly skilled process. The tea leaves are rolled by hand to break the cell walls, release the internal juices, and form the shape of the tea. For example, in the production of some high - end oolong teas, such as Tieguanyin, hand - rolling is often used to create a tight and curly shape, which is beneficial for the release of flavor during brewing.

Mechanical rolling: With the development of technology, mechanical rolling has become more common. Rolling machines can process a large amount of tea leaves at one time, improving production efficiency. These machines can adjust the rolling pressure and time according to the type of tea, ensuring consistent quality.

Fermentation degree control: Fermentation is a key process in the production of black tea, oolong tea, and some post - fermented teas. In black tea production, full - fermentation occurs. The tea leaves are placed in a warm and humid environment, and under the action of enzymes, the polyphenols in the tea leaves are oxidized, resulting in the formation of the unique red color, mellow taste, and rich aroma of black tea. In oolong tea production, semi - fermentation is carried out. The degree of fermentation is carefully controlled, usually between 10% - 70%, which gives oolong tea its complex flavor, combining the freshness of green tea and the mellowness of black tea.

Fermentation environment management: The temperature, humidity, and oxygen supply during fermentation need to be strictly controlled. For example, the optimal fermentation temperature for black tea is usually around 25 - 30°C, and the humidity is about 90%. Proper oxygen supply can promote the oxidation reaction of polyphenols, while too much or too little oxygen can affect the quality of the tea.

Firing methods: There are several firing methods, including pan - firing, oven - firing, and sun - drying. Pan - firing is often used in green tea production. The tea leaves are stir - fried in a hot pan to stop the enzymatic reaction, evaporate the remaining water, and fix the shape and flavor of the tea. Oven - firing is suitable for some teas that require more uniform drying and flavor - fixing, such as some types of black tea. Sun - drying is a traditional method, especially in the production of some special - type teas, like Yunnan Pu - erh raw tea, which gives the tea a unique sun - dried flavor.

Firing temperature and time control: The firing temperature and time have a significant impact on the quality of the tea. For example, in pan - firing green tea, if the temperature is too high, the tea leaves may be burnt, resulting in a bitter taste; if the temperature is too low, the enzymatic reaction cannot be effectively stopped, and the quality of the tea will be affected.

Automated production lines: In modern tea processing factories, automated production lines are widely used. These lines can complete multiple processing steps, from withering to packaging, in a continuous and efficient manner. They can also accurately control the processing parameters, ensuring the stability of tea quality.

High - tech detection equipment: New - type detection equipment, such as near - infrared spectrometers, can be used to quickly analyze the chemical components of tea leaves during processing, such as the content of polyphenols, amino acids, and caffeine. This helps tea producers adjust the processing technology in a timely manner to obtain the desired tea quality.