Abstract: As three representative Congou black teas in China, Keemun Congou, Chuanhong Congou, and Dianhong Congou black tea still rely on personal experience in their brewing process, and there is no scientific guidance for brewing. This study focused on Keemun Congou black tea as the experimental subject, with extraction yield (EY) and total dissolved solids (TDS) as indicators of tea infusion quality, survival analysis was used to determine consumers’ acceptance of the optimal flavor balance and concentration of tea infusion. A brewing control chart of Keemun Congou black tea was established and the ideal profile method (IPM) was selected to test its application on Chuanhong Congou and Dianhong Congou black teas. The survival analysis identifies the optimal EY as 3.46% to 5.68%, the optimal TDS as 0.14% to 0.29%, and the optimal tea-to-water ratio (g∶mL) as 1∶20 to 1∶30, based on which a nine-grid Keemun Congou brewing control chart was established. Through evaluator validation via the IPM, it was found that for Chuanhong Congou, most of three infusions fell within the 50% core ideal zone, indicating good overall applicability. In contrast, first brew of Dianhong Congou black tea infusion was outside the 20% acceptability threshold, reflecting lower evaluator acceptance and poorer applicability. This study indicated that the brewing control chart established based on small-leaf Congou black tea can effectively guide the brewing of ideal tea soup for medium and small-leaf Congou black tea, but its applicability to large-leaf Congou black tea still needs to be improved.

Key words: Congou black tea, survival analysis, brewing control chart, ideal profile method, consumer testing