<P> Tannins help prevent oxidation, an important role in a wine's aging potential . As age - worthy red wines mature, tannin molecules gradually accumulate and precipitate out of the wine in the sediment . </P> <P> Certain wine styles have much less tannin content than others, due to reduced maceration time (grape juice contact with the grape pulp, including sources of tannin such as stems, seeds). Grape varieties like Sangiovese, Gamay (Beaujolais), Tempranillo, and the Italian grapes Dolcetto and Barbera, are less tannic . Also, grapes grown in certain wine regions are less tannic, like French reds from Burgundy, and Spanish wine regions like Spanish Riojas . </P> <P> French reds from Bordeaux, and Italian reds like Barolo and Barbaresco (both made from Nebbiolo grapes), are particularly tannic . Vintage port is also very tannic when young, as are wines made from the Syrah (Shiraz) and Cabernet Sauvignon grapes . </P> <P> A quick way to identify these lower tannic wine bottles on a store shelf is to look for the sloped shoulder "Burgundy bottle". This is specially true for European wines, but several new world wineries have also adopted traditional bottle shapes to help consumers distinguish their wines . </P>

What is in red wine that gives me a headache