The processing of harvested leaves starts with drying and withering. The primary aim of this stage is the dehydration of the tea leaves. In the process of withering the leaves lose up to 55 percent of water.
Usually tea leaves are withered in the shade, in the well-ventilated room, but some varieties are withered in the sun. Tea drying can be natural, and lasts from 10 to 24 hours, or artificial, and then in the special drying places the time is reduced by 3-5 times in comparison with the natural drying. Withering time is largely dependent on the required variety, but in the process of natural withering, also on the weather (humidity, temperature, wind).
In the drying process, tea is usually laid up in a thin layer (to 12 cm) in baskets or on special pallets, which can be multistorey. Modern drying technologies are using synthetic netting for tea laying, which are moved (tea is being shaken for even laying), and the artificial air supply of the required temperature and humidity is used.
Besides the dehydration, in the process of withering, the cell turgor falls out (pressure), leaves become more flexible and less breakable, but the juice - heavy-bodied and thicker. All these processes guarantee a qualitative fermentation and curling process.
Drying quality is usually determined by weight loss of the raw; however, there are different standards, depending on tea, in different regions. For example, in Northern India a good weight loss in the withering process is 40%, and in the South India and Ceylon - 50%.