Tannins

Tannins are natural organic compounds (polyphenols) found in the skins, seeds, and stems of grapes, and also passing into wine from oak barrels. They are one of the key components of a wine's structure, above all red, and largely determine its character, flavour, and capacity for ageing.

Tannins are responsible for the sensation of astringency in the mouth — that characteristic dry, slightly rough feeling well known from strong tea or unripe persimmon. In wine tannins perform several important functions: they form the “skeleton”, structure, and body of the wine, give it a pleasant bitterness that balances the fruitiness, and, most importantly, act as a natural preservative-antioxidant, thanks to which tannin-rich wines (like Cabernet Sauvignon) are able to age and develop for years. In young wine tannins can be firm and aggressive, but over the years they gradually “soften”, becoming velvety and smooth, and the bouquet more complex. The level of tannins depends on the grape variety, the method of winemaking, and the ageing. The ability to assess tannins is an important skill of the taster and sommelier. They are the invisible frame on which a great red wine rests.