Tasting tannins

Tannins cannot be smelt or tasted; they cause tactile sensations. A significant development of the 1990s was a keener appreciation of the different sorts of sensory impact of tannins on the palate (see texture). In Australia, this led in particular to the development of a mouthfeel wheel rather like the aroma wheel. Tannins may be variously described as hard, bitter (if accompanied by bitterness), green, ripe (if perceptible but only after the impact of fruit that has reached physiological ripeness has been felt on the palate), coarse, grainy, wood (if obviously the effect of cask ageing), long chain (an American expression for polymerized), short chain, and polymerized. Research in the US by Revelette et al. has shown that it is not just the quantity of tannins in a wine that determines its astringency but also the quality of those tannins, specifically their tendency to ‘stick’ to another surface such as the mucous membranes.