Tannins
Tannins protect wine from oxidation during barrel aging. The wood tannins extracted from a new barrel protect the wine from over-oxidation during the slow process needed for tannin polymerization and wine development. Recognised by the OIV, tannins are permitted for use in grape wine in over 50 countries worldwide.
Oenological tannins are extracted from nutgalls, or a wood rich in tannin: chestnut trees, oak, exotic wood, or grape seeds. Tannins are made up of a mixture of glucosides either from gallic acid (gallotannins), or from dilactone, ellagic acid (ellagitannins) (hydrolysable tannins) or from a mixture of proanthocyanidines (condensed tannins). Tannins are used to facilitate the clarification of wines and musts. Tannins must not change the olfactory properties and the colour of wine.
Oenological tannins range in colour from pale-yellow to reddish brown, with an astringent taste. Tannins are partially soluble in ethyl acetate, water-soluble, ethanol and methanol for condensed tannins and insoluble in most organic solvents, with the exception of ethanol and methanol for hydrolysable tannins. For further substance information, please see the International Oenological Codex.
Synonym(s): tannic acid
CAS Number: 1401-55-4
E Number: 181
INS Number: 181
International Organisations
Codex Alimentarius
-Classification, Food Category, Functional Class and Recommended Usage is not available at this time.
International Organisation of Vine and Wine (OIV)
-Classification Tannins – additive Food Category Wine (grape) Functional Class Clarification Recommended Usage (International Code of Oenological Practices – Annex: Maximum Acceptable Limits) GMP
Classification Category 2 – Naturally occurring in grapes and treatment residual in wine
Recommended Usage
Good Manufacturing Practice (GMP)
As outlined in the OIV’s International Code of Oenological Practices, Tannins are used:
Tannins are used to facilitate the clarification of wines and musts. Tannins must not change the olfactory properties and the colour of wine.
Usage in Winemaking:
Tannins are naturally occurring in wine but additions are made for the following purposes and problem corrections:
- Redox buffer
- Raisined fruit
- Sun-damaged fruit
- Unripe grape tannins
- Structural/textural, mouthfeel modification
- Increased substrate for micro-oxidation
- Limit the activity of laccase
- Help to precipitate proteins
- Help to modify aromas, including vegetative aromas
- Help increase ageing potential
- Possibly to help stabilise red wine colour
Of the above-listed purposes for tannin addition, mouthfeel modification (increase astringency and drying perception) is frequently the goal.
See FIVS technical papers for more information - click here.
