Black tea processing•Drying

Drying is the last step in the initial processing of black tea and an important step in ensuring the quality of black tea.

Translation of drying methods and techniques

Gongfu black tea is generally dried using a Tea Dryer Machine. Dryers are divided into manual louver type and chain dryers, both of which can be used. Generally, automatic chain dryers are used. The dryer baking operation technology mainly controls temperature, air volume, time and leaf thickness, etc.

(1) Temperature is the main factor affecting the quality of drying. Taking into account the requirements of evaporated water and endoplasmic changes, “high temperature for gross fire and low temperature for full fire” should be mastered. Generally, intrgral tea leaf dryer are used, and the air inlet temperature of the raw fire is 110-120°C, not exceeding 120°C. The temperature of the full fire is 85-95°C, not exceeding 100°C; the cooling time between the raw fire and the full fire is 40 minutes, not more than 1 hour. The hair fire adopts moderate high temperature, which can promptly stop enzymatic oxidation, quickly evaporate water, and reduce the effect of heat and humidity.

(2) Air volume. Under certain conditions, increasing the air volume can increase the drying rate. If the air volume is insufficient, the water vapor cannot be discharged from the Hot Air Drying Oven Machine in time, resulting in high temperature, humid and stuffy conditions, which affects the quality of tea making. If the air volume is too large, a large amount of heat will be lost and the thermal efficiency will be reduced. Generally, the wind speed is 0.5m/s and the air volume is 6000m*3/h. Adding moisture removal equipment on the top of the dryer can increase drying efficiency by 30%-40% and improve drying quality.

(3) Time, the rough fire should be high-temperature and short, generally 10-15 minutes is appropriate; the full fire should be low-temperature and slow-drying, and the time should be appropriately extended to allow the fragrance to fully develop, 15-20 minutes is appropriate.

(4) The thickness of spreading leaves is 1-2cm for hairy fire leaves, and can be thickened to 3-4cm when the fire is full. Appropriately thickening the thickness of the spreading leaves can make full use of heat energy and improve drying efficiency. If the spread leaves are too thick, not only the drying efficiency cannot be improved, but the tea quality will be reduced; if the spread leaves are too thin, the drying efficiency will be significantly reduced.

degree of dryness

The moisture content of hairy fire leaves is 20%-25%, and the moisture content of full fire leaves is less than 7%. If the moisture content is too low due to drying in the Drying Machine, the tea sticks will easily break during transportation and storage, causing loss and not conducive to maintaining the appearance.

In practice, it is often grasped based on experience. When the leaves are 70 to 80% dry, the leaves are basically dry and hard, and the young stems are slightly soft; when the leaves are dry enough, the stems will be broken. Use your fingers to twist the tea sticks to form powder.