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Tannins and oenology
Natural solutions to improve the quality of red and white wine
The tannins obtained from the maceration of the grape skins, represent one of the main constituents of wine, especially red wine.
Tannins have several properties due to their chemical structure and they have a variety of uses for the oenological industry. Silvateam produces a wide range of chestnut, quebracho, Tara, gallnut, oak and grape tannins in order to achieve:
The stabilisation of the colour during winemaking is a fundamental step to increase the longevity of a good red wine. The use of tannins, both hydrolysable and condensed, integrates the natural tannin texture present in wine and promotes the formation of stable complexes with anthocyanins in the case of red wine and flavonols in the case of white wine. Moreover tannins preserve the polyphenols naturally present in grapes, maintaining an unaltered typical taste and sensory perception of the grape.
Improvement of the organoleptic characteristics of the wines
Tannins, especially the hydrolysable ones, give structure and flavour to wines that are lacking in texture and taste. The oak tannins enhance the smell and taste of the finest wines, bringing lovely vanilla and liquorice notes, as well as roundness and mouthfeel. They also mask the herbaceous and bitter notes of polyphenols. Among the condensed tannins, those from grapes and green tea are the most suitable for improving the structure and flavour profile of wines.
The gray mould, caused by the fungus Botrytis cinerea, is one of the most important diseases occurring in the vineyards and thus affecting the quality of the wine. Botrytis cinerea causes oxidation reactions with polyphenols and aromatic precursors of the wine. The use of tannins as antioxidants inhibits the action of the main oxidase enzymes responsible for the degenerative process, such as the grape tyrosinase and the fungal laccase.
In oenology, tannins are mostly used to complex unstable proteins in the wine. The hydrogen bond that tannin forms with the protein is the same as that created in a sensorial way by tannins and salivary protein. Proline, the main protein component of saliva, binds the tannin and the precipitate obtained creates the sensation of astringency on the palate as a result of the reduction of its lubricant action.
Tannins are used as filter aids in order to clarify must and wine without changing the aromatic structure.
Another important property of hydrolysable tannins, especially for the gallotannins, is to complex metals such as copper and iron, forming chelate complexes that precipitate, thus reducing the metal content in solution.
Tannins enhance the antimicrobial properties of sulphur dioxide, inhibiting the growth of microorganisms.