What is the role of tannins in wine?

Tannins play a crucial role in providing structure and aging potential in wine. They are polyphenolic compounds found in the skins, seeds, and stems of grapes, as well as in the wood of barrels used for aging. The presence of tannins contributes to the mouthfeel and texture of the wine, often leading to a sense of astringency.

One of the key functions of tannins is their ability to stabilize wine over time. As wine ages, tannins can polymerize, meaning they can bond with each other and other compounds in the wine, which helps to soften the overall taste and allows for the development of more complex flavors. This is why wines that possess higher tannin levels, such as Cabernet Sauvignon or Nebbiolo, are often regarded as having better aging potential.

While tannins do provide some level of astringency that can balance sweetness, they do not sweeten the wine directly. Moreover, tannins do not play a direct role in fermentation or preventing spoilage, as those functions are primarily associated with yeast activity and other preservation methods, respectively. Thus, their main contribution is to the structural integrity and aging capability of the wine.