Effect of an agent (lat. Astringent), the ingredients of which contract skin tissue or mucous membranes (lat. Astringere = contract). The astringent forms a connection with the proteins of the skin and the mucous membranes, which form a protective wall (membrane). Medicines such as alum are used to stop bleeding. In the context of a wine description, astringent is understood to mean a complex of sensations which is expressed by a rough effect that dries out the mouth mucosa or “contracts the mouth”. This is due to high levels of phenols ( tannins ), which occur especially in the woody parts of fruits such as stems, pods, skins and seeds. These are e.g. B. almonds, chestnuts, green nuts, artichokes and anthocyan (Dye-rich) varieties, The latter, like the ones shown in the picture, mostly have a dark (black) berry color.
The astringent substances cause a contraction of the organic tissue in the mouth, prevent saliva secretion and thus have a roughening effect on the mucous membranes. However, it is (although it seems) none olfactory or Taste sensation but a tactile or trigeminal Stimulus (regarding the sense of touch) on the mucous membranes of the inner cheeks and the nasal cavity and must not be included bitter or angry be confused. The sensation is also from the wine temperature dependent and is amplified at low temperature. The bandwidth can range from weak to just barely positive intrusive to the already negative aggressive pass.
Astringency is usually primarily a trait of young people red wines, The impression can change during the bottle aging or in the course of aging process mitigate significantly and through that precipitate the causative substances even disappear completely. The astringent effect has a positive effect on low-acid red wines in most cases and can also stimulate the appetite. at White wines however, this is usually an undesirable negative property and is considered phenolic designated. See also under wine address,
Images: Ursula Brühl, Doris Schneider, Julius Kühn Institute (JKI)