Bottle aging reactions during

Chemical reactions occurring during barrel and bottle aging... 

During the barrel and bottle aging of wine, many oxidative reactions modify the structures of the original procyanidins. Phenolic compounds in wine may be fractionated into four classes (Section 6.4.6) that have characteristic reactivity to gelatin (Table 6.9). According to the percentage of each of these classes in a given wine, it is... 

Stabilizing reactions that affect wine colour and clarity, structural changes in the phenolics and new aroma formation all take place during oak wood aging. None of these reactions occurs in tanks or bottles, which are inert, do not interact with the wine, and do not allow the controlled oxidation that takes place in oak barrels. 

Chemical or enzymic reactions occurring after fermentation, during aging of the wine in vat, barrel and bottle. 

Certain heterocyclic compounds are also important aromatic substances in wines, such as pyrazines in Cabernet Sauvignon and Sauvignon Blanc wines (see Section 8.2.11.1.7) and both enantiomers of 3-hydroxy-4,5-dimethyl-5if-furan-2-one (sotolon), which occur in white wines, sherries and are a key component of the typical aroma of aged Port wines. The precise chemical reactions leading to the formation of bouquet substances are not yet widely known. There are two types of reactions that produce bouquet constituents oxidation, which is characterised by the presence of aldehydes and acetals (e.g. in Madeira-type wines) and reduction (such as in quality table wines after a period of bottle maturation the flavour of low-quahty wines does not improve under the same conditions, but instead maturation often leads to a loss of freshness). During wine aging, glycosides of terpenic alcohols and... 

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