Somehow I've noticed that the standard tip for a pint of beer is $1.00 here in San Francisco. Even an employee of one of my favorite beer bars insisted that it was "standard" and "decided." By whom? I asked. He couldn't tell me.
It seems to me that a dollar tip for a $3.50 pint is too much. Particularly since I've found so many people pouring pints behind bars utterly indifferent and sometimes hostile, though there are a few nice folks out there (Barclay's in Oakland stands out). If someone is pouring, say, 40 pints an hour I think they are making too much money. For bartenders who are mixing complex drinks, it is a different story. But for the kind of slackers that give me sloppy wet pints and a sneer, I think that 50 cents should be enough.