Maturation and aging can be considered as a group of reactions and series of changes that occur in wine during storage and lead to wine improvement. Boulton et al (1996) suggested that wine aging should not be viewed as single procedure and single event but rather a family of changes. They further suggested a distinction between the term maturation and aging. Term maturation used for the changes during bulk storage and aging used for the changes during bottle storage. The key difference is that during bulk storage a wine is likely to be exposed to air where as in bottled it is stored in essentially anaerobic conditions. For the purpose of this presentation when we say oak aging of red wine we also mean oak maturation of red wine.
The basic procedure of red wine production is outlined in the diagram. An important point in making red wine is that the fermenting must consists of juice skins and seeds. As a result, the composition of red wine is determined by the constituents extracted from skins and seeds in addition to those present in the juice.
Jenny Savits, Enology Field Specialist