Is it really necessary to finish a bottle of wine in one sitting, or is it safe to recork it and drink it another day? In the case of a red wine, do you refrigerate it or leave it on the counter?
Wines can, in fact, go bad. This process is called oxidation, and at first this process is what makes wine so full of aroma and flavor. The oxygen in the air gradually mixes with the wine, and after several days, this can produce sourness, bitterness, tartness, or other unpleasant flavors in the wine.
To slow down this process, you can refrigerate the wine. If the wine is red, it is advisable to leave the bottle out to adjust to room temperature (or slightly below) about 45 minutes before serving, as this is the temperature at which the wine is meant to be drunk. There are some devices that will create a vacuum in the bottle, thus slowing the process of oxidation down even further.
However, the best rule of thumb is the “3-Day Rule.” Either drink the wine within three days or throw it out. That way, you won’t risk serving guests or yourself soured wine. Enjoy wine when it’s at its best—after uncorking the bottle and letting the air open up the wine’s subtle notes.