I am yet to come across a bottle of wine with a 'best before' or 'use by' date. However, it is well known that an unopened bottle of wine tends to spoil after a while - typically years, and quite a lot sooner for inexpensive wines.
High quality wines are often considered age-worthy, with those high in residual sugar such as Sauternes having a legendary aging potential, for 100 years or more in some cases. Professional reviews of fine red wines often indicate a drinking window decades into the future.
So to my question: is there any way to calculate roughly the drinking window of a given wine? Do the pros have a secret formula based on the grape variety, alcohol level, residual sugar, sulfites, and/or other factors? Or is it just down to experience - sampling thousands of wines of various vintages?
What motivated this was the recent discovery of a ten year old bottle of cheap (£5) white wine in a cool dark store room at work - a 2012 Bergerac. Of course, I could just pop the cork and see what it's like, but it had me wondering why retailers never seem to indicate a best before date (assuming correct storage and good closure). Furthermore, can drinking a moderate amount of a wine way past its best cause illness?
I note that bottled beer, with its lower alcohol content, always carries a clear 'best before' date.