However, these odor components are short-lived. They often disappear in less than a year or so. Consequently, these types of wines are best consumed when they are young, and the nose is still fresh and fruity. Bouquet components decrease, remain constant or increase in intensity as the wine ages. By products produced by lactic bacteria can give wines a lasting buttery attribute.
Wines stored in oak barrels slowly accumulate vanillin and other substances from the wood.
Wine acids react with alcohols to produce volatile esters, and during bulk storage, oxidation slowly changes many wine ingredients. All these different materials contribute to the bouquet of the wine. After the wine is bottled, oxygen is no longer available, and a different type of aging begins to take place. Winemakers call these transformations reduction reactions because they take place without oxygen. This is the bouquet that develops after a wine has been in the bottle for some time.