Is Slight Oxidation Necessary to Age Wine?
Today, Budburst had an interesting post about the different types of off aromas in wine and where they originate. The controversial subject of wine closures centers on TCA or cork taint. While this is certainly the central issue, underneath the surface is the question of how oxidation helps wine age. Aside from aesthetic reasons, this is the chief reason that natural cork is still used for high quality wines.
I have heard the argument from proponents of natural cork that over time, tiny amounts of oxidation will interact with the wine and bring out its more developed flavors and bouquet. But how much oxygen is enough? And what is the exact threshold before a wine will spoil? These are questions that are usually answered with something like, “wine is a mysterious beverage, and no one really knows how the aging process actually occurs.”
If slight oxidation will benefit wine with age, it seems a bit counterintuitive that almost every step of the production process for most wines is concerned with minimizing oxygen contact as much as possible. Many wines that undergo barrel aging are left in contact with their lees to minimize the effects of oxidation. Just before the cork is inserted, any oxygen is flushed out of the neck of the bottle. People are advised to not subject their aging wine to temperature swings as the cork will expand and contract and risk oxidation. One of the main drawbacks of synthetic corks is that they are not as pliable as natural ones, and thus more susceptible to the ill effects of temperature fluctuation.
> It is undeniable that oxidation plays some role in winemaking and aging.
The brownish rim of a well aged Cabernet Sauvignon is proof that oxidation helped make the wine what it is. The chief benefit that I am aware of is that slight exposure to oxygen will help soften astringent tannins. And the consensus seems to be that only natural cork will allow for the right amount of oxygen exposure.
It will be very interesting to see how well one of the few, age-worthy red wines that are currently being bottled with screw caps will develop over the next decade. Will this wine taste very similar to when it was bottled, or are there other variables at work that will make it taste aged? Maybe then the effects of oxidation on wine aging will be more apparent.