ISO/TS 5617:2025

This document specifies a method to classify the six tea types (black tea, green tea, white tea, oolong (Blue) tea, dark tea and yellow tea) based on statistical analysis of chemical compositions. The key X1-X6 determinants (total catechins, caffeine, theanine, EGCG/total catechins, theanine × theanine, theanine × caffeine) for tea chemical classification were extracted from these critical compositions by statistic methods, from large-scale chemical analysis of samples of six tea types, which can be used as principal components to classify the particular tea by Fisher’s step-by-step discrimination formulas. This document is applicable to the classification of both primary and refined teas, mainly suitable to those teas produced from China, not applicable to reprocessed teas.