Equilibrium Moisture Content of Tea Leaves and Stems for Tea Manufacture

Abstract

The equilibrium moisture content which is one of the physical properties of tea shoots was measured for leaves and stems. The results were summarized as follows.
1. The equilibrium moisture content of tea stems was higher than that of leaves, and its difference increased when the atmospheric humidiy increased.
2. The equilibrium moisture content also depended upon temperature, and became lower as the temperature rised on the same humidity.
3. The hysteresis which gave higher moisture contents during desorption than those during adsorption in the epuilibrium moisture content was found, and its width decreased'when the temperature rised.
4. Halsey equation which was shown as follows was most successfully applied to the measured values after the examination of the several equations.
lnφ=-a/Mg^b
(See table 6 for the coefficient a and b)
5. The following equation was recommended as the equilibrium moisture content equation
which contained a term of temperature.
lnφ=-a/e^bTM^C/T
(See table 8 for the coefficient a, b and c)