How long will an unopened bottle of wine keep?

Most red and white wines made or distributed in the U.S. are meant to be consumed  within a year of two of release. Most such wines cost $20 or less.  Depending on the grape, vintage, and storage conditions, some red wines keep for longer periods of time. Some of the very finest may keep for decades. However, this typically isn't the case with the majority of wines purchased at liquor stores or supermarkets.  Finer wines suitable for extended storage usually can be found at fine wine shops or boutiques. These tend to be specialty shops.
 
Source(s):
Wines.com "How Long Can I Store Wine?"