Beverage & Wine

Tannin

Also: tannins, tannic acid

A class of bitter, astringent plant polyphenols — extracted from grape skins/seeds/stems, tea leaves, oak wood, and other plant matter — that create the drying, structural "grip" in wine, tea, and other foods.

/TAN-in/From French 'tanin', from 'tan' (crushed oak bark used in leather tanning) — tannins were first identified as the compounds in oak bark that bind and preserve animal hide.

Definition

Tannins are a broad class of astringent, bitter plant polyphenols that bind to and precipitate salivary proteins, producing the characteristic dry, puckering, grippy sensation known as astringency. In wine, tannins are extracted primarily from grape skins, seeds, and stems during maceration, and — in barrel-aged wines — from oak wood itself; they provide structure, aging potential, and a textural counterpoint to fruit and acidity, and soften over years as individual tannin molecules polymerize into larger, less reactive chains. Condensed tannins (proanthocyanidins) dominate in grapes and are largely responsible for red wine's structure, while hydrolyzable tannins (gallotannins, ellagitannins) are more typical of oak wood and are picked up during barrel aging. The same broad chemistry underlies the astringency of black and green tea (catechins and theaflavins), unripe fruit, walnut skins, pomegranate, and many legumes and grains. Tannin's astringency is not a taste in the strict sense (like sweet or bitter) but a tactile, chemesthetic sensation caused by the temporary loss of the mouth's lubricating salivary proteins.

In use

“The 2015 Barolo showed firm, grippy tannin on the finish — a sign it would benefit from another five to ten years in bottle before the structure softened.”

Related terms

MacerationAstringencyPolyphenolAnthocyaninOak AgingCatechin

References

1.Jancis Robinson — 'The Oxford Companion to Wine', 4th ed. (2015), Oxford University Press
2.Jamie Goode — 'The Science of Wine' (2005), University of California Press
3.On Food and Cooking — Harold McGee

Confidence: high

Notes

Tannin sources in the kitchen and cellar

Beyond wine, tannins are the backbone of black and green tea (theaflavins and catechins), the drying sensation of unripe persimmon and banana, the astringency of walnut skins and pomegranate, and the structure of oak-aged spirits, which pick up hydrolyzable tannins (ellagitannins) from the barrel wood itself.

Tannin management in the kitchen

Astringency can be softened by binding tannins to protein and fat — hence the classic pairing of tannic red wine with fatty, protein-rich meat, or milk added to strong black tea. Cooking, long maceration, and micro-oxygenation all encourage tannins to polymerize into larger, softer-tasting chains over time.