Description (also drying or unripe tannins or tannins) for the negatively understood mouth-drying, rough or strongly astringent effect in the context of a wine's flavour. However, this is not a flavour, but a trigeminal (tactile) sensory impression. These are particularly fine-grained tannins that give the impression of fine sand in the mouth and taste rather unpleasantly "edgy". They are also known as "bad tannins". As a rule, this does not change as the wine matures. This is caused by unripe grapes.
In contrast, the "good or ripe tannins" are coarse-grained and convey a "soft" impression. Incidentally, an original exercise can be used to check whether the tannins are "good" or "bad". If you can whistle after tasting a tannin-accentuated wine, it was "good". Another characteristic is that they stimulate salivation. A term used in the USA for an overly pronounced tannic flavour is tannin to lose.
For me, Lexicon from wein.plus is the most comprehensive and best source of information about wine currently available.
Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)