Wine vapor can indeed be combustible. However, wine in checked baggage is (usually) not regulated by the FAA.

With regards to all alcoholic beverages, the FAA specifically uses ABV as it's guide for what is allowed and what is banned. (It actually is as simple as going by the proof.)

Alcoholic beverages with more than 24% but not more than 70% alcohol are limited in checked bags to 5 liters (1.3 gallons) per passenger and must be in unopened retail packaging. Alcoholic beverages with 24% alcohol or less are not subject to limitations in checked bags. This includes beers and most wines.