Tannin is a polyphenol, an organic molecule found in the fruit, leaves and bark of plants. There are 2 main types: condensed tannins and hydrolysable tannins. They give the wine its character and sometimes even its astringency, that "raspy" side.

Where do the tannins in wine come from?

The different parts of the grape

Grapes contain condensed tannins, known as catechic tannins, in :

  • skin of the grains especially when it's thick
  • the seed , which explains its astringent crunchiness,
  • the bunch of grapes (stalk)

Oak barrels

Oak is a wood that naturally contains hydrolysable tannins and more specifically ellagic tannins.. They therefore develop in wine when aged in barrels, the tannic capital of this material diminishing over time.

Addition of oenological tannins

The winemaker can also resort to tannisage during vinification. This tannic addition consists of the incorporation of exogenous tannins:

  • Condensed (grape seed extract, grape skin extract, exotic wood extract such as quebracho, etc.),
  • ellagic hydrolysates (oak extract, chestnut extract, etc.),
  • gallic hydrolysates (gall nut extract, etc.).

Tannins and tasting: what does it mean?

One of the characteristics of these phenolic compounds is that they react with our spit , leaving us with the impression of a dry mouth. Hence that rough mouthfeel! Several terms are used to describe the tannin in a wine and the taste it gives.

Terminology Taste description
Fade out Imperceptible in wine, so called "tannin-free"
Silky Present in very small quantities, very light wine
Supple Little presence, the wine's roundness and mellowness come through
Tender Present, well-balanced and letting the fruit shine through
Firm Very present, but not astringent
Hard, astringent Too present, very raspy, bitter taste

Terminology Fade out
Taste description Imperceptible in wine, so called "tannin-free"

Terminology Silky
Taste description Present in very small quantities, very light wine

Terminology Supple
Taste description Little presence, the wine's roundness and mellowness come through

Terminology Tender
Taste description Present, well-balanced and letting the fruit shine through

Terminology Firm
Taste description Very present, but not astringent

Terminology Hard, astringent
Taste description Too present, very raspy, bitter taste

The balanced presence of tannins therefore benefits the aromatic properties of a vintage as well as its structure. But their benefits go even further!

What role do tannins play in oenology?

In the wine quality

Condensed tannins promote :

  • stabilising the colour of the wine,
  • improving its structure as it ages.
As for hydrolysable tannins, they enable :
  • easier clarification of the must,
  • its protection against oxidation, but also against reduction and the undesirable tastes that result,
  • refining the organoleptic characteristics of the cuvée.

Towards our body

When condensed, tannins have recognised health benefits.Their chemical structure, which is similar to that of flavonoids, gives them an antioxidant effect that helps to prevent certain cardiovascular diseases... So here's to your health, but it goes without saying that they should be consumed in moderation!

Why are some wines more tannic than others?

The tannic character of a wine is influenced by a number of factors, including :

  • the colour of the grape variety,
  • the thickness of the fruit skin, which varies according to the grape variety (which is why table grapes are distinguished from wine grapes!),
  • growth and therefore the ripening of the grape, which is then less concentrated in phenolic compounds when ripe,
  • the intensity of pressing and therefore the extraction of tannins,
  • the maceration process (duration, temperature, presence of stalks, etc.),,
  • tanning process,
  • malolactic fermetnation, if it takes place
At the end of the winemaking and ageing stages, tannins are generally present at a level of 1 to 4 g/l in red wines and 0.1 to 0.3 g/l in white wines.