Tannin is a characteristic found in red grape skins and seeds as well as oak. They cause an astringent or bitterness when either too much is extracted from grapes or when young. As a wine matures, either in a fermenting vessel such as oak or stainless steel, the tannins soften and meld into the wine.
What does Tannin do? #
Tannin also gives wine structure, and is thereby one of two elements that allow wine to age well. Like a strong backbone when young will likely result in better posture when old, so a strong backbone in a young wine results in better aging.
Wines with High Tannin #
Cabernet Sauvignon, Shiraz, and certain types of Grenache have very thick skins. This means that there is a higher skin to juice ratio – and thus these wines in particular are more tannic.The one exception to this rule is Nebbiolo (Barolo/Barbaresco wines) as Nebbiolo has very thin skins but extremely high levels of tannin. However, all of these wines also have reputations for aging quite well. This is in part due to the tannin level of the wines.
Wines with Low Tannins #
Pinot Noir, Gamay, and Barbera on the other hand, have very thin skins. This means that there is a very low skin to juice ratio, thus are less tannic. These wines typically do not age for as long as the previously mentioned group. However, they can age well – but not because of the tannin content. Rather, these wines will age because they all have high acidity levels. High acidity is another key element for a wine to age.
Tannins are also found in oak – when oak is new and wines are fermented or matured in it the oak will impart flavors (vanilla and baking spices if French oak, and coconut and dill flavors if American) as well as tannin. If you feel a drying sensation in your gums at the front of your mouth, this is typically attributed to wood tannin. If you feel a drying sensation in the back of your mouth where your wisdom teeth were/are, that is grape tannin.
Want to see how well you gauge tannin in wine? Try tasting with my tasting worksheet, as seen in my book, Wine Label Shopping. Simply subscribe below to get an e-mail sent with the free PDF.