In an article titled, A study on chemical estimation of Puerh tea quality, Yuerong Liang et al found that the chemical composition of infused Puerh Tea and the sensory quality of the tea are correlated.
Chemical compositions and infusion colour differences of seven puerh tea samples and their correlation to sensory quality were investigated. The results showed that the puerh tea contained 37.1 mg g-1 caffeine, 15.7 mg g-1 amino acids, 67.0 mg g-1 polyphenols and 8.41 mg g-1 total catechins, on average. Among the 17 tested volatile compounds, n-valeraldehyde was not detected. The most abundant volatile was -ionone and the next was linalool oxide II. Infusion colour analysis showed that the puerh tea had deep hue with E ranging from 66.8 to 79.2. Spearman’s linear correlation analysis showed that total quality score (TQS) of the puerh tea was significantly correlated to concentration of amino acids, linalool oxide II and infusion colour indicator E. Five components were extracted from the 34 tested indicators by principal component analysis and were regressed on the TQS to produce six Pearson’s linear regression equations for estimating sensory quality of puerh tea, among which two were statistically significant, ie TQS = 57.47 – 0.18geraniol + 0.33polyphenols – 1.14n-caproaldehyde – 1.38linalool oxide I + 0.21caffeine (p < 0.01) and TQS = 57.42-0.03Citral + 0.33polyphenols – 1.14n – caproaldehyde – 1.40linalool oxide I + 0.20caffeine (p < 0.01).
Puerh is an aged tea from China that is fermented and matured to develop a unique mellow, slightly wet earthy character. The finest puerhs are aged for up to 50 years and become more mellow and soft over time. In China, this category of tea is considered to be a medicinal beverage that helps metabolize fats. It is ideal for digestion and is said to help prevent hangovers.