Any game benefits from "a beer or two." More relaxed "beer and pretzels" games with a strong camp or hack 'n slash component can benefit from up to 4-6 beers per person.
Ultimately, it's really about the kind of people you are gaming with. Drinking socially, like everything else, is a learned skill. If the people in your game have not invested energy and/or time in acquiring this skill, even a small amount of alcohol can cause your game to go awry. In this way, it is somewhat fair to engage in a little age discrimination; there are few 18 year old gamers who have mastered social drinking, whereas a group of 30+ players should all have.
In my view, alcohol and gaming are a very good mix. The D&D group I'm in every week polishes off 2-3 bottles of wine (amongst 3-5 players and the GM) per session and that's pretty much ideal. Unless your group is very young or involves intense immersion or puzzle-solving, go for it.