Definition - What does Oxidative Aging mean?
Oxidative aging is a process used in the elaboration and aging of wines which purposely allows controlled amounts of air to oxidize wine. This style of aging is more familiar in the making of Jerez (Sherry) from the region of Andalucia, Spain. It is also the same type of aging for Madeira, called maderization.
WineFrog explains Oxidative Aging
Oxidative aging is a method by which winemakers permit their wines to be exposed to the air via controlled measures. This process imparts specific characteristics to a wine, such as aromas and flavors of toffee and raw walnuts with notes of marmalade and fruit cake.
Oxidative aging is a signature method for two of the most famous wines in the world; Jerez (Sherry) and Madeira.
For the making of Jerez in the region of Andalucia, Spain, barrels of wine are only filled 2/3 of the way in order to allow free head space, permitting the presence of air. The controlled oxidation of these wines is performed due to a yeast found locally in the region called flora. This flora creates a layer of film on the surface of the wine, thus allowing only small amounts of oxygen to oxidize the wine over a long period of time. The result is the production of oloroso and amontillado wines.
For Madeira, a secondary fermentation starts naturally. The wine is purposefully exposed to air, creating the signature color, aromas and flavors of the wine that are similar to walnuts and candied citrus peel.