Research of sunlight withering room and its withering effect on white tea

In this paper, the energy-efficient sun withering room and a novel variable-frequency continuous withering machine were used for white tea leaf withering to optimize the processing condition, which aims to substantially improve white tea quality, while reduce the energy budget and labor cost by realizing fully automation of white tea leaf withering. The results show that sun withering room for white tea in Fuding city should be facing 5 degree south by west, with the roof angle of 22o. Variable-frequency continuous withering machine can realize automatic alternation of sun withering and natural withering. The total solar radiation intensity and temperature in the machine exhibits gradient as (from high to low) level 4 > level 3> level 2 > level 1. The daily variation of total solar radiation is in the range of 34 to 695 W/m2, and accordingly the daily variation of temperature is from 17.8℃ to 32.7℃, both of which comply with the requirement of white tea withering condition. It demonstrates that the quality of white tea withered in the facility is much better than that withered by traditional natural withering. The study results can provide a reference for fully automation of white tea leaf withering in facility.