Quality and yields of black tea Camellia sinensis (L.) O. Kuntze responses to harvesting: A review on experiences from Kenya

Abstract

Tea beverages, from tender shoots of Camellia sinensis L., are the most widely consumed fluids after water. The young tender shoots of the plant are harvested using various plucking methods. Incorrect plucking leads to yield and quality declines. It is therefore necessary that this process is optimised. Extensive research showed changes in the chemical composition, quality and yields of black tea due to plucking standards. Black tea quality deteriorates as the leaves become older and the rate of decline varies with crop varieties. A plucking standard of two leaves and a bud is recommended in most tea growing countries. However, due to rising harvesting costs, many tea producers are resorting to various mechanical harvesters. Mechanical harvesters or shears produce lower quality black tea compared to hand plucking. But this evens out after the plants are subjected to continuous/long term mechanical harvesting. There is decline in quality with long plucking intervals even when the plucking standard of two leaves and a bud is maintained. Although a plucking standard of two leaves and a bud is a good compromise between yields and quality, there are tea varieties which can withstand coarse plucking standard without substantial quality losses. Quality of black tea declined with coarse plucking standards and long plucking intervals. With unselective plucking and long plucking intervals produced leaf with a high proportion of mature (coarse) leaf beyond two leaves and a bud which resulted in low quality black tea. Selective plucking standard of up to two leaves and a bud improved black tea quality even at long plucking intervals, but yields are reduced. Short and fine plucking standards ensure production of high quality black teas. Soft physically withered leaves produce superior plain black tea parameters and inferior aroma compared to hard physically withered leaves at all plucking standards. Irrespective of plucking standards shorter fermentation duration improved black tea quality.