The trough withering method is widely used in modern tea factories, particularly in South India. This method involves placing freshly plucked tea leaves on large, shallow troughs, through which air is blown to remove moisture. The length and width of the troughs vary, but they are typically between 60 to 120 feet long and 6 to 15 feet wide, depending on the factory’s capacity and technology.
Trough withering provides a more controlled environment for withering compared to traditional methods, such as spreading leaves on mats or floors. The airflow in troughs can be adjusted to achieve uniform moisture loss throughout the leaf bed. By using fans, factories can regulate the temperature and humidity of the air, which is essential for achieving consistent results.
Modern troughs are often equipped with two axial fans, which help circulate air evenly across the entire surface of the leaf bed. This ensures that all the leaves receive the same amount of air and moisture is removed uniformly. Newer trough designs also allow for energy conservation by turning off one fan after the desired level of withering is achieved, reducing electricity consumption.
One of the advantages of trough withering is that it can accommodate larger volumes of leaves compared to traditional methods. In some factories, troughs can hold up to 30 kg of leaves per square meter. This makes it easier for large-scale producers to process tea more efficiently and ensures that the leaves are handled gently to avoid damage.
Overall, the trough withering method offers a more controlled and efficient way of withering tea leaves, making it the preferred choice in many modern tea factories. It not only helps achieve better consistency in the final product but also reduces energy consumption and labor.