How long does an opened bottle of wine last in the refrigerator?
(Simply plugging the cork back in that is, and not using any vacuum contraption.)
The short answer is approximately 3-5 days, but it all depends on the type of wine. There are a number of factors at play when it comes to the life of wine, after it has been opened.
These include acetic acid bacteria that consumes the alcohol in wine and metabolizes it into acetic acid and acetaldehyde. This causes the wine to have a sharp, vinegar-like smell. Additionally, the alcohol can oxidize, causing a nutty, bruised fruit taste, that robs the wine of fresh, fruity flavors. These are both chemical reactions, and so the lower the temperature you keep a wine at, the slower this will happen.
Please see link for full reference and detailed breakdown of How long wine lasts after opening: How Long Does an Open Bottle of Wine Last?