Like mentioned above, high abv beers tend to be good candidates for aging. Lighter beers and/or highly hoped beers are the ones you want to drink fresh. Cellar temperatures are ideal, but if your like me, that isn't always possible. I store mine in an interior closet on the bottom shelf to try to keep the temperature swings to a minimum. I have several bottles that are 2+ years old and they are doing just fine. I don't think humidity is a factor with a metal cap.