By “go bad” I’m assuming you’re not wondering if your wine joins a gang or becomes a criminal.
Bear with me. My humor (much like an opened bottle of wine) can go bad.
Yes, opened wine will eventually lose its original flavor and can develop a vinegar taste. When a bottle is opened it’s exposed to oxygen. The oxygen interacts with the wine and begins a chemical process that will make the taste of the wine different. And by different I mean bad. Essentially, oxygen provides fuel for bacteria to produce molecules that affect the taste. And when you think about it, that’s kind of criminal.
So how long have you got to fight this crime?
That depends on the wine.
Let’s assume that you put the cork back in all open bottles and put sparkling wines and white wines in the refrigerator, and that you put red wines in a cool, dark place. The following chart gives you a pretty good estimation of how long your wine will last under these conditions.

Why do some wines last longer than others?
For a few reasons.
First, fuller-bodied whites like oaked Chardonnay are not going to last as long as lighter whites because through their aging process they’ve already been exposed to a certain amount of oxygen. It’s not enough to make the wine taste bad, but it has given the wine kind of a “head start.”
Second, red wines have tannins. And the higher the tannins (and acid) the slower the oxidization process will be when a bottle is opened, giving red wines just a bit longer time to enjoy. But remember, different red wines have different tannin levels. So your Syrah is going to last longer than your Grenache.
Third, fortified wines like Sherry and Port will last much longer because of their higher alcohol and sugar content. They’ve got higher alcohol and sugar because a grape-based liquor like brandy is added during the production process. The higher alcohol and sugar will slow down the oxidization process. Port can last three weeks or longer, and Sherry can go for a couple months.
So how can you make your opened bottle last longer?
The key is to slow down the oxidization process, and there are a couple of steps you can take to do this.
1. Recork the bottle right after you pour. Too often we pour a glass and let the bottle sit out uncorked, letting in lots of oxygen.
2. Put the bottle in the refrigerator – even the reds and fortifieds. Oxidation is a chemical process and the cooler temperature in the refrigerator will slow down that process. Just remember to take the bottle out to warm up before serving the next time. For more on that, see my previous post on serving temperature.
There are also a couple of gadgets you can try to make your opened wine last longer.

The cheaper option is vacuum stoppers. These are stoppers that you place on the bottle then use a pump to remove the oxygen. Do they work? Maybe. Some wine experts love them; some think they’re a waste of money. There have been some studies done on these that have been fairly inconclusive about their effectiveness. But they’re pretty affordable (you can get the pump and two stoppers for $15 or less) and easy to use. I use them and believe I get about an extra day from an opened bottle with them.
The more expensive gadget option is the Coravin®. At about $200 for the basic model, this had better work! And according to wine experts, it does. Essentially this contraption sticks a needle through the cork so you aren’t removing it. It then injects an inert gas into the bottle to increase the pressure so you can pour out wine through the needle. Then you remove the needle and the cork expands to reseal the bottle. So no oxygen gets to the wine and therefore there’s no oxidization. In full disclosure, I’ve never used the Coravin® but I hope to one day.

So there you have it. Opened wine does go bad, but you can take steps to make it last longer. Personally, I think the best way to ensure an opened bottle’s taste is to invite enough friends over to finish the bottle together because wine should be enjoyed with others.
But wait! One more question: What about boxed wine? Doesn’t it say on most boxes of wine that it will last six weeks?
Ok, technically that’s two questions, but yes, boxed wine will last longer. And it had better, since a lot of boxes of wine have the equivalent of four bottles or more! What makes boxed wine last longer is the spigot and bag help keep oxygen from getting to the wine. When you pour a glass, air doesn’t get in the bag. The volume of what’s in the bag (wine) just gets smaller. I don’t have experience seeing how long a boxed wine can last, but perhaps that’s an experiment I’ll try and report back to you.
But for now I’m going to go make sure that bottle of pinot noir I opened last night hasn’t gone and joined a gang.
Cheers!
(Note: Mention of products or brands on this blog does not imply endorsement.)
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