If kept for long enough, wine eventually turns into vinegar after being opened. Depending on one's taste for vinegar, this can be a plus or a minus.
Wine goes bad after opening from prolonged exposure to oxygen and the action of lactic acid-producing bacteria. Oxygen exposure oxidizes chemical components of the wine, while the bacteria ferment the wine in the same process used to produce wine vinegar.
Boxed wine does go bad but it stays fresh between 30 to 60 days after opening. Boxed wine are basically wine that is contained in a bag with a cardboard box outer covering. To dispense the wine, a hole is cut along a dotted portion on the box and a spout or a tap is pul...
Wines stay fresh for a couple of days after opening; about 2 days for white wines and 3 days for reds according to Real Simple. Because whites have more acid, they tend to stay fresh slightly longer.
If stored properly, a bottle of red wine can last up to a week after being opened. Without proper storage, it will only last a day or two.
In general, red wines start to lose their aromas and flavors and begin to taste acidic 2 or 3 days after opening. However, the more bodied a wine is, the more likely it is to have a higher tannin-content. Tannins reduce a wine's deterioration upon contact with oxygen an...
To preserve the freshness of the wine, it is best to store open wines in the refrigerator. Allow refrigerated red wines to warm to room temperature before serving.