Tannin in Wine: What Are Tannins and How Do They Work?

How Does Tannin Get Into Wine?

Tannin in wine mainly develops through contact with the solid parts of the grape: skins, seeds, and sometimes stems. When making a red wine high in tannin, these components ferment along with the juice. This allows a particularly large amount of tannins to make their way into the wine. Red wine tannin is therefore more intense and noticeably stronger than in white wine, which is usually made without skin contact during fermentation. Oak barrels, where some wines age, also release additional tannin into the wine and contribute to its structure and aging potential.

What Effects Do Tannins Have?

Tannin in wine influences not only the flavor, but also the structure and aging potential of the wine. Tannin creates that characteristic dry, bitter flavor as well as the dull, fuzzy sensation on the tongue. This quality, known as astringency, will feel familiar to anyone who drinks black tea. This tannin effect also protects the wine as a natural antioxidant and extends its shelf life.

This is especially clear with red wines high in tannin: the longer the wine ages, the softer and rounder the tannins become. Color intensity is also shaped by tannins. Tannins can only be tasted, not smelled, which makes their effect in the mouth all the more striking.

Does Tannin Cause Headaches?

Tannin side effects are often discussed, especially in connection with red wine tannin. In the past, tannins in wine were considered problematic, since they can form complexes with enzymes and proteins in the gut, potentially inhibiting the absorption of iron or other nutrients. Headaches are often blamed on tannins, but studies show that other substances like histamines, sulfites, or simply drinking too much wine are usually the real culprits.

These days, the positive effects of tannins are better known: some tannins have anti-inflammatory and antibacterial properties, and can help slow the rise in blood sugar. Overall, tannins in wine are considered safe for health, and you'll also find them in tea, nuts, and cocoa.

Are Tannins Only Found in Red Wines, or in White Wines Too?

Tannin in wine is mainly found in red wine, since it's fermented with skins, seeds, and sometimes stems, the main sources of tannins in wine. White wines, on the other hand, have significantly lower tannin content, since they're usually fermented without skin contact. In exceptional cases, such as contact with oak barrels or the use of whole grape clusters, white wine can also contain small amounts of tannin, this is especially true for natural wines or orange wines.