Tea drying machine
Drying is the second step in the initial processing of tea, mainly through the evaporation of tea moisture by heat energy, forming a specific aroma and taste of tea, solidifying its appearance, and facilitating storage and quality assurance. The main functions of tea drying are: firstly, to evaporate water and solidify the appearance; The second is to use high temperature to stop residual enzyme action and prevent discoloration; The third is to form specific aromas and flavors.
The factors that affect the quality of tea during the drying process mainly include drying method, drying frequency, drying temperature, drying time, and leaf dosage. During the drying process of tea, it is necessary to dry it in stages according to the water loss law and physicochemical characteristics of the tea (depending on the different quality requirements of the tea, it can be divided into two or more times). Before each drying, it is necessary to cool and regain moisture appropriately to ensure that the tea loses moisture evenly and achieve the best drying effect. When drying in stages, it is necessary to grasp the parameter relationship between drying temperature, time, and leaf feeding amount. The first drying mainly focuses on evaporating water and inhibiting residual enzyme activity. The leaf feeding amount should be small, the drying time should be short, and the temperature should be appropriately high; Subsequent drying is a key stage in the formation of tea color, aroma, and shape. The temperature should be appropriately lowered, the amount of leaves added should be moderately increased, and the drying time should gradually be extended.
Common tea drying methods include drying, stir frying, and a combination of drying and stir frying. Drying is a method of drying tea leaves by heating them with hot air to evaporate moisture. The tea dried by drying method is mostly natural, with fresh aroma and fresh taste, such as Mount Huangshan Maofeng, Lu’an Gua Pian, etc. Frying is a method of drying tea leaves by utilizing the heat generated by the pot wall and the inner surface of the drum to heat the tea leaves, thereby causing them to evaporate moisture. Tea leaves that are dried by stir frying have tight strands, high aroma, and mellow taste, such as West Lake Longjing tea, Sanbei Xiang tea, and Songluo tea.
Common drying equipment includes bucket dryer, chain plate dryer, baking and flavoring machine, re drying machine, bottle dryer, octagonal dryer, cylindrical dryer, glow dryer, etc
Bucket dryer
A bucket dryer, as it is a single-layer tea spreading machine with good breathability, often dries tea leaves with bright colors. It is generally used for drying high-quality tea leaves with high color requirements. Bucket dryer, commonly available in models such as three bucket and five bucket.
Chain plate dryer
Chain plate dryer is currently the most widely used tea drying equipment. This type of dryer has high efficiency and has become a series. According to the actual leaf spreading area, there are 8, 10, 16, 20, 25, and 50 types. For example, the 8 type dryer has an actual leaf spreading area of about 8m2, and so on for the rest. Generally, type 20 and above dryers are mostly used for drying black tea, while type 20 and below are mostly used for drying green tea.
The baking and flavoring machine adopts a box type structure, with a relatively uniform temperature inside the box, easy control of drying time and temperature, and convenient operation. It is more commonly used in the fragrance extraction process of famous tea, and less commonly used in the foot drying process of famous tea.
Fixation machine
The re drying machine can meet the needs of different types of tea. It not only has the functions of drying tea leaves, removing impurities, preserving color, and protecting seedlings, but also has the functions of drying stir fried tea leaves and tightening strips. It can also avoid problems such as gray tea color, easy breakage, and inability to balance extraction and drying during the drying process. It can be used for extracting tea leaves, dried feet, and enhancing fragrance.
Bottle type stir fry dryer
The bottle type stir fry dryer consists of a conical body with two large heads connected together, and the overall shape resembles a bottle. It is a commonly used model for long stir frying green tea.
Octagonal Frying and Drying Machine
Octagonal style stir fry dryer is a cylindrical stir fry dryer composed of two octagonal cones connected by large heads. This equipment has a strong color changing effect and is commonly used for the final glow drying of green tea in the initial production process.
Electromagnetic drum dryer
Cylinder type stir fry dryer, with a cylindrical heating cylinder, has the same shape and structure as a drum type withering machine. Currently, the application of cylinder type stir fry dryer is the most widespread in the stage of fragrant tea circulation rolling stir fry.
Huigan machine
The glow dryer has both forming and drying functions, which can straighten and smooth the surface of tea strips, and also have a certain effect on improving the aroma of tea leaves.
TIPS
What is the optimal moisture content for finished tea after drying?
Tea is a dry agricultural product. Research has found that when the moisture content of tea is between 3% and 5%, water molecules exist in a single molecular layer and bind with tea component molecules, as if a water film is covering the surface of tea component molecules, isolating them from oxygen in the air and preventing their oxidation and deterioration; When the moisture content of tea leaves is less than 3% to absolute dryness, the tea component molecules lose the protection of the water film and are directly exposed to the air, making them susceptible to oxidation by oxygen in the air; When the moisture content of tea leaves is greater than 6%, it will cause chemical changes in the components and molecules of tea leaves, such as denaturation and decomposition of chlorophyll, darkening of color, rapid reduction of flavor substances such as tea polyphenols and amino acids, sharp reduction of aromatic substances such as dimethyl sulfide and phenylethanol that make up the aroma of new tea, and a significant increase in volatile components that are detrimental to aroma, leading to a deterioration in tea quality.
Therefore, the optimal moisture content for finished tea is 3% to 5%, with a maximum not exceeding 6%.