Q. I often read about tannic wines but what does this mean?
A. Tannins are a group of phenolic compounds that are found in wine. They come mainly from the skins and pips of grapes, but also sometimes from the stalks and from wooden barrels. Tannins make wine slightly bitter or astringent and produce a drying sensation in the mouth. Strong tea, coffee and very dark chocolate are also high in tannin.
Tannins can be removed from wine through fining, or added artificially to give structure or body. Red wines that are fermented on the grape skins are higher in tannins than white, which are not. Orange wines, which are made like a red wine from white grapes, do have tannins.
Some grape varieties, such as Nebbiolo and Cabernet Sauvignon, have very thick skins and so the wines tend to be deeply coloured and high in tannins
Tannins give the impression of texture and body often found in red wines. They also play an important role in ageing wine. As wine ages, the tannins and other polyphenols drop out as sediment, making the wine seem softer as well as paler in colour.
Some grape varieties, such as Nebbiolo and Cabernet Sauvignon, have very thick skins and so the wines tend to be deeply coloured and high in tannins. Others, such as Pinot Noir, have very thin skins, and are pale in colour with light tannins.
If the tannins are from ripe grapes, they help create a pleasant texture. If not, they can give an unpleasant harsh astringency. Some tannins are quite smooth and soft, others more strident.
Tannins generally taste better with food, cutting through the proteins in rich, fatty meats and cheeses. Some people develop headaches from tannins and cannot drink red wine.