Kinetics of tea infusion. Part 2: the effect of tea-bag material on the rate and temperature dependence of caffeine extraction from black Assam tea

Extraction experiments of tea inside tea-bag material were carried out at different temperatures. The rates of extraction were measured for caffeine from black orthodox Assam tea into distilled water. The leaf size used was 1.18–1.40 mm and the results obtained were compared with those of loose tea. The first order rate constants for the tea-bag tea were found to be 29% smaller than those of loose tea. The activation energies were found to be 45±2 and 43±2 kJ mol−1 for loose tea and tea-bag tea, respectively. These results show that the tea-bag material slows the infusion.