Even when drinking liberals are collectivists and conservatives are individualists:

When a group of diehard liberals gathers on Wednesday nights at the 331
Club, they all throw money into a kitty and share pitchers of beer.
They talk about social issues, local political races, or if all else
fails, football.

When
a group of diehard conservatives gathers at Keegan’s on Thursdays, they
pay their own tabs. And they drink Guinness or an expensive import.
Rather than blather on about politics, they turn their attention to a
game of trivia.

I got this link from my daughter
who first noticed a similar phenomenon on band trips in high school.
Everyone was required to bring a six-pack or a 2-liter bottle of soft
drink on the trips, at which time they would all be put into a communal
tub of ice. Predictably, the people who brought Chek or some other
off-brand drink would drink the Coke and Pepsi brought by others.
More often than not, she noticed, it was the lefty kids who drank brand
name drinks while contributing generics. She complained and quit
putting her drinks in the communal tub, which brought accusations that
she was a capitalist counter-revolutionary. Well, not really. I
think it was more like accusations that she was not a team player or
something. Still, I think that’s part of why she’s a conservative
blogger today.