Tannins are an important descriptor for wine tastings and it basically refers to the dryness, bitterness and astringency of a wine
Tannin is a naturally occurring polyphenol found in plants, seeds, bark, wood, leaves, and fruit skins. Polyphenols are macromolecules made of phenols: complex bonds of oxygen and hydrogen molecules (Yep, wine is a science).
You will find tannins in the skins, seeds and stems of grapes. Tannins can also come from the oak barrels used for the vinifcation of many wines.
Tannins in wine add both bitterness and astringency, as well as complexity. They are most commonly found in red wine, although some white wines have tannins too (from ageing in wooden barrels or fermenting on the skins).
Tannins are essentially a wine’s pucker power. Generally, they are more dominant in younger red wines that haven’t had the time to soften up with age. Tannins are often described as the textural component that “dries the mouth” when drinking red wines. They are also responsible for giving red wines a defined structure or body. Similar to how a skeleton provides support for the body and allows movement.
Tannins are often one reason why it’s recommended that you allow a wine to breathe before drinking it. The air softens the tannins, particularly in young red wines.
By no means are tannins a good or bad thing, they are there to bring that balance into your wine.
