Thin layer drying of black tea

This paper describes the experiments used to determine the kinetics of tea drying. New thin layer drying apparatus was designed and built to measure t he very high rates of drying found at the start of drying, and the results show that the Lewis equation satisfies. The drying rate constant proved to be a linear function of temperature and airflow rate, indicating that tea d rying is not only diffusion limited but also a function of convection. The results were validated on independent experiments. (C) 1999 Silsoe Research Institute.