Phenolic content in tea green tea. Catechins constitute about 25% of the dry mass of a fresh tea leaf, although total catechin content varies widely depending on species, clonal variation, growing location, season, light variation, and altitude. They are present in nearly all teas made from "Camellia sinensis", including white tea, green tea, black tea and oolong tea. Of all the catechins in tea, EGCG is the main subject of scientific study with regard to its potential health effects. 4-Hydroxybenzoic acid, 3,4-dihydroxybenzoic acid (protocatechuic acid), 3-methoxy-4-hydroxy-hippuric acid and 3-methoxy-4-hydroxybenzoic acid (vanillic acid) are the main catechins metabolites found in humans after consumption of green
Tea tasting Tea tasting Tea tasting is the process in which a trained taster determines the quality of a particular tea. Due to climatic conditions, topography, manufacturing process, and different clones of the "Camellia sinensis" plant (tea), the final product may have vastly differing flavours and appearance. These differences can be tasted by a trained taster in order to ascertain the quality prior to sale or possibly blending tea. The ISO 3103 standard describes a standardised method for brewing teas in order to make meaningful sensory comparisons between them. It is not a particularly useful standard for many teas, however, requiring a