⌈ Basics ⌉

What is tannin in wine?

The compound that makes red wine grip your tongue

Quick answer

Tannin is a naturally occurring polyphenol found in grape skins, seeds, and stems. It creates the drying, gripping sensation you feel on your tongue and gums when drinking red wine.

Tannin is one of wine's four structural pillars alongside acidity, alcohol, and residual sugar. It comes primarily from the skins, seeds, and stems of grapes, and is extracted during maceration — the period when grape juice stays in contact with solids after crushing.

The astringent, mouth-drying sensation tannin produces is most obvious in young, full-bodied red wines. When you take a sip of a young Barolo or Cabernet Sauvignon and feel your gums tighten and your mouth dry out, that is tannin at work.

Oak ageing adds a secondary layer of tannins from the wood itself. These oak-derived tannins tend to be softer and rounder than grape-derived tannins, and contribute to the cedar, vanilla, and spice notes associated with barrel-aged wines.

Key takeaways

Tannin is a polyphenol from grape skins, seeds, and stems.
It creates a drying, gripping sensation on the palate.
Tannin acts as a natural preservative and allows red wines to age.
High-tannin wines (Barolo, Cabernet Sauvignon) benefit from decanting.
Protein-rich foods like steak soften the perception of tannin.

Tannins serve an important biological role: in the grape, they deter animals from eating the fruit before seeds are ripe. In wine, they act as a natural preservative. High-tannin wines — Barolo, Hermitage, aged Bordeaux — can improve for decades because tannins bond with oxygen and slow oxidation.

As a wine ages in bottle, tannin molecules polymerise — they join together to form larger chains, which fall out of solution as the brown sediment seen in old red wines. This process softens the wine's texture: what started rough becomes silky. Decanting an aged wine separates the liquid from this sediment.

Winemakers control tannin extraction through several decisions: how long the juice macerates on the skins (more time = more tannin), fermentation temperature (warmer temperatures increase extraction), the number of pump-overs or punch-downs, and whether to use whole clusters or destemmed fruit. Understanding tannin helps you predict how long a wine will age well and which foods will match it best — high-protein foods like red meat soften the perception of tannin dramatically.

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