We talk about wine, and wine tasting, like we talk about fine dining and baking: as if it were an art. And it is! But like cooking and baking, winemaking is also a science. Having a basic understanding of chemical processes can help us better understand wine. One such process, which can make or break your bottle of wine, is oxidation.
Oxidation occurs when an object is exposed to oxygen. Zoom in to the molecular level: oxidation causes a reaction in which the atoms in the object lose electrons. When an atom loses electrons, it transforms. Zoom back out, and you’ll see the object begin to break down. Iron, for example, becomes rusted and brittle when oxidized. When food experiences oxidation, it speeds up the decomposition process. A cut apple, for example, turns brown and mushy, or your avocado develops a yucky brown film: both are examples of oxidation. This is why cut fruit has a much shorter shelf life than whole. Once its interior is exposed to oxygen, the aging process occurs rapidly, sometimes in as little as a few hours!
Wine experiences similar transformations. There’s two sides: “breaking down” and “opening up.” In general, when wine is exposed to oxygen, it ages prematurely. An oxidized batch of wine–or, one that has been over-exposed to oxygen–will have duller flavors with nuttiness taking over those fresher notes. This is “breaking down.”
Exposure to oxygen also creates a bacteria-growth environment. Grapes have a naturally-occuring bacteria that will turn the alcohol in wine into acetic acid, which will make it taste like vinegar. Good news! This bacteria requires oxygen in order to grow, so as long as you keep the bottle sealed, your wine will be fine until it’s opened. And even if you do drink it, it probably won’t make you sick; it just won’t taste nearly as good as a fresh bottle.
If we remember from our previous blog post on wine types, one of the defining characteristics of white wine is its fruity freshness. If oxygen exposure cuts freshness, then white wine needs to be kept as far away from oxygen as possible. White wine, therefore, must be aged and bottled with minimal exposure. There are some white wines–known as oxidative wines—that use moderated and controlled oxygen exposure to bring secondary, more savory notes and flavors. Sherry, for example.
For red wines, oxidation is a key part of production. Controlled oxidation during the aging process of red wines helps add certain notes to the wine, as well as deepen the color. But the key word is “controlled.” Too much oxygen can easily spoil the batch. This is why red wine is often aged in barrels and corked; allowing for the steady introduction of a small amount of oxygen, creates complex flavors and richer colors.
What about the whole “let the bottle breathe” notion? Introducing oxygen to a just-opened bottle or freshly poured glass is known as “opening up”–the other side of oxidation. This can only occur in those first moments of oxidation. The aromas expand–making it easier to identify the notes you’re smelling–and softens the mouthful of wine.
Creating the perfect bottle of wine is all about intention and control. Interested in learning more about our winemaking process? Stop by our vineyard for a glass and chat with our exceptional staff!