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

Do Pinot Noirs and Chardonnays from Burgundy improve with age?

Wine Spectator's expert Dr. Vinny consults Burgundy expert Bruce Sanderson on how long to …

Apr 6, 2020

If red meat goes with red wine, what about plant-based “meat”?

Wine Spectator's expert Dr. Vinny asks food-and-wine pairing master Harvey Steiman for tips …

Apr 3, 2020

Is it OK to store potatoes and other vegetables in my wine cellar?

Wine Spectator's expert Dr. Vinny consults Idaho's Dr. Potato on storing potatoes in a wine …

Apr 1, 2020

Which grapes are used in the sparkling wine Blanquette de Limoux?

Wine Spectator's expert Dr. Vinny, with an assist from associate editor Gillian Sciaretta, …

Mar 30, 2020

Should I sip wine with food in my mouth to appreciate a wine-and-food pairing?

Wine Spectator's expert Dr. Vinny explains that enjoying wine and food together is all …

Mar 27, 2020

In wine and grapevines, what’s the difference between a “clone” and a “selection”?

Wine Spectator's expert Dr. Vinny calls in vine expert Carole Meredith to explain how a …

Mar 25, 2020