Many people judge Tea based on a single sip. If they find it bitter and Astringent, they conclude it's not good tea, which is an unfair judgment of tea's “bitterness” and “astringency.”
In fact, those who understand tea do not judge its quality solely by its bitterness or astringency. The bitter and astringent flavors are just part of tea's inherent character, always present but never the only or constant feature.
A tea with a “bitter and astringent” flavor isn't necessarily bad; it can often be a high-quality tea. The intensity of the bitter and astringent flavors depends on the amount of these substances present in the tea. The primary bitter compounds in tea include Caffeine, theobromine, theophylline, anthocyanins, tea saponins, bitter amino acids, and some flavanols.
The astringency in tea is mainly due to polyphenols, aldehydes, and Iron, with catechins being particularly significant. Catechins with a fat-like structure have a stronger astringency and are found in much higher concentrations in young leaves compared to older ones.
Under normal circumstances, teas made from young shoots (one bud and one or two leaves) tend to be more bitter and astringent than those made from one bud and three or four leaves. Therefore, Pu'er tea with a “bitter and astringent” flavor often indicates a high degree of tenderness and a higher grade. This also explains why lower-grade teas generally have a milder taste.
For Pu'er tea, if the tea is tender, has aged aroma, and exhibits low bitterness and astringency, it is likely an aged tea. Over time, the bitter and astringent substances decompose and transform, resulting in a smoother taste. However, there are other reasons for bitterness in tea. Teas made from leaves affected by pests and diseases often have a more intense bitterness, even becoming unpleasantly bitter or having a fishy odor. This kind of bitterness is distinctly different from the inherent bitterness of tea.
Regardless of the quality of the tea, astringency is an inherent characteristic. The astringency in tea is primarily caused by polyphenols (mainly catechins, phenolic acids, condensed phenolic acids), aldehydes, and iron, which affect our sense of taste. Although bitterness and astringency are often discussed together, they belong to different taste categories.
Astringency is a strong sensation that is difficult to describe, occupying a unique place in the world of taste. It is not quite “numbing” but has a slight numbing effect, not quite bitter yet closely related. The astringency is like eating an unripe persimmon, creating a Drying sensation opposite to smoothness.
Among the various tastes in tea, astringency often occupies an unfavorable position, sometimes even less favored than bitterness. Bitterness can help clear heat and detoxify, hence the saying “bitter medicine cures.” However, astringency makes it hard to swallow and is hardly enjoyable. As a result, tea makers often go to great lengths to reduce astringency in their teas.
In the “kill-green” stage of tea production, insufficient temperature or time can result in a strong “green astringency” in the tea. After a certain period of storage and aging, Pu'er tea undergoes oxidation and polymerization, which can significantly reduce the astringency in the tea liquor.
A tea that is bitter and astringent is not necessarily bad, but a tea that quickly transforms its bitterness and astringency is definitely a high-quality tea. Bitterness and astringency can be seen as proof of the richness of the tea's internal components. When bitterness and astringency dissipate quickly, it indicates good tea-making techniques and quality tea.
Therefore, don't unfairly judge the bitterness and astringency in tea; instead, learn to appreciate and distinguish them. Only then will you not miss out on those fine teas.