Why is oxidation bad for wine?

Ask Dr Vinny

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.

Dear Dr. Vinny,

Why is oxidation bad for wine?

—Mikayla, Victoria, Australia

Dear Mikayla,

Whenever I write about oxidation (and aeration), I like to bring up apples. You know how if you bite into an apple and set it aside, the apple will start to turn brown and then take on a nutty flavor? It’s because once you’ve broken the skin of the apple and exposed its flesh to oxygen, it starts to react with the oxygen in the air.

Same with wine. A wine can become oxidized if it’s exposed to too much oxygen while it’s being made, or if too much oxygen gets into the bottle because of a faulty closure. You might have firsthand experience with oxidation if you leave wine in your wineglass overnight and then take a sip, or revisit a bottle that’s been open for a week. The wine’s flavors and aromas will flatten, and those nutty, Sherry-like notes replace the fresh flavors the wine had. Oxidation will also change a wine’s color to brown and brick tones. What is chemically happening is that the wine’s phenols are susceptible to combining with oxygen, and the wine’s ethanol starts to break down and shift into other compounds, like acetaldehyde.

The ill effects of oxidation take hours if not days to show themselves, however. Sweet wines, wines with higher acidity, and more tannic wines tend to have more resistance to oxidation, but after a while, all wines will suffer from too much oxygen.

—Dr. Vinny

Wine Flaws Ask Dr. Vinny

More In Dr. Vinny

How can I preserve an intentionally wine-stained shirt?

Wine Spectator's expert Dr. Vinny explains the pros and cons of using red wine as a fabric …

Aug 16, 2019

What exactly does it mean that a wine can express "terroir"? Is it a smell? A taste?

Wine Spectator's expert Dr. Vinny explains the elusive concept and expression of terroir.

Aug 14, 2019

What is the ideal "total acidity" for Cabernet Sauvignon?

Wine Spectator's expert Dr. Vinny explains total acidity, and how it interacts with other …

Aug 12, 2019

Are some wines better-suited to being canned than others?

Wine Spectator's expert Dr. Vinny explains which wine styles have been most successful in …

Aug 9, 2019

How can a wine taste like fruits other than grapes?

Wine Spectator's expert Dr. Vinny explains how all those complex flavors and aromas get …

Aug 7, 2019

Why are people so fascinated/obsessed with wine?

Wine Spectator's expert Dr. Vinny explains a few of the reasons we love wine.

Aug 5, 2019
WineRatings+

WineRatings+

Xvalues

Xvalues

Restaurant Search

Restaurant Search