Astringency
Definition
The dry, puckering sensation in your mouth caused by polyphenols (mainly catechins and tannins) in tea binding with proteins in your saliva. Often confused with bitterness, astringency is a tactile feeling rather than a taste - it's the same sensation you get from unripe fruit or dry red wine.
Why it matters
Some astringency is desirable and adds structure to a tea's body, but excessive astringency usually signals over-steeping, water that's too hot, or low-quality leaf. Learning to distinguish pleasant astringency from harsh drying helps you dial in your brewing and evaluate quality.