What happens to opened wine — and how to know when it's gone bad

You might have an opened bottle of wine from a recent celebration and wonder, "Is this still good?"

Wine that's been open for too long may not make you sick — but it won't taste the way it was intended, according to the "Wine Country" blog.

Leaving wine open for too long can strip its brightness, dull its aromas and mute its flavors, experts say.

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In the worst cases, opened wine can develop a sour, vinegary taste.

What's a good rule of thumb for opening and storing wines?

Dana Sacco, owner of The Empty Glass in Tomball, Texas, said there's a reason opened wine doesn't taste good forever.

Once opened, it's "exposed to more oxygen, heat, light, yeast and bacteria," the wine bar owner said.

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Those factors cause chemical reactions that alter the quality of the wine, Sacco said, which is why refrigeration is key.

"Storing wine in lower temperatures will help slow down these chemical reactions and keep opened wine fresher longer," she said.

How long your wine can last depends heavily on the type, the wine expert said.

Sparkling wines can last between one and two days without losing too much of their flavor, while light white wines and rosés can last between four and five days, according to Sacco.

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Rich white wines should generally be consumed within three to five days after opening, with red wine having a similar timeline, Sacco said. 

She noted that port is the sturdiest wine in this regard, as it can be consumed between one and three weeks after it's opened.

In some cases, Sacco said, opening wine can actually improve its taste.

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"Aerating wines helps soften tannins, release complex scents and elevate your overall tasting experience," Sacco said. "Full-bodied reds are normally better aerated."

"Wine is supposed to be fun and educational, along with enjoyable," she added.

If you want to preserve your wine at the best quality, Sacco recommends using wine pumps, which reduce the oxygen inside the bottle.

"It helps the wine stay better longer," she said.