On to tannins. These are natural compounds—polyphenols, if you want to get technical—that can come from the skins, stems, or seeds of grapes, as well as the wood barrels in which a wine may have been aged. (The latter is more often responsible for the tannins in white wines, which usually spend less time than reds soaking in skins and seeds.) Tannins are more a texture than a taste, and therefore distinct from whether the wine is “dry,” which refers to the absence of sweetness.
