We call a wine “tannic” as if it were obvious, without always knowing what the word covers. Tannins are the compounds that give red wine its backbone and that sometimes dry out the mouth. They are natural polyphenols, present in the grape and in the wood of the barrels. They largely decide a wine’s structure and its ability to age. This article explains where tannins come from, what they do, why they dry the palate and how they evolve over time.
Where do tannins come from?
Tannins have two main origins. The first is the grape itself, the second is the wood used during ageing.
Tannins from the grape
They come from the skin, the pips and the stems. They are called condensed tannins. These dominate in a red wine, all the more so when maceration is long.
Tannins from the wood
They come from oak barrels during ageing. These are called hydrolysable tannins. They add woody notes and complete the structure of the wine.
What do they do?
Tannins form the backbone of the wine, its structure on the palate. They also stabilise the colouring matter, which helps a red keep its colour.
Their antioxidant effect protects the wine during ageing, with an added antiseptic action against certain bacteria. They are what give great reds their ability to cross the years.
Why do tannins dry the mouth?
Tannins react with the proteins in saliva and precipitate with them. This reaction produces the rough sensation, that feeling of the tongue sticking to the palate that we call astringency.
The richer a wine is in tannins, the more marked this sensation. A quality tannin stays firm without being aggressive: we then speak of fine or well-integrated tannins.
How tannins evolve over time
Tannins do not stay fixed. With time and slow micro-oxygenation, they soften and integrate, offering a more silky texture on the palate.
This is why a young, tannic red often benefits from being aerated before serving. Our guide on whether to decant or aerate a wine explains when and how to do it.
Frequently asked questions
Does white wine contain tannins?
Very little. Tannins mainly concern reds, since they come from the skin and pips during maceration. A white aged in oak may however show a small share.
Are strong tannins a sign of quality?
Not in themselves. What matters is the balance between tannins, fruit and acidity. A very good wine has tannins that are present but harmonious.
How can firm tannins be softened?
By aerating the wine before serving, or by letting it age. Time and contact with air naturally round out tannins.
Going further
Understanding tannins helps you read a wine better on the palate. To go further, learn to recognise wine aromas and follow our introduction to wine tasting.
The reds of Château d’Arsac, in the Margaux appellation, reflect this search for fine, balanced tannins.
