A girl who likes beer; all kinds of beer. She knows what she wants, like an amber ale or stout, not just crappy lite beer. This is a girl who will order herself a beer in a bar, she doesn't want a pussy Cosmo or screwdriver.
"Did you see that girl go right for the keg? It's nice to see a Beer Girl here."
"Look at that chick drinking Irish Red! She must be a Beer Girl."
B- "Ok, we've got vodka and mixers, and a fridge full of beer, what can I get you?"
Girl- "Beer me."
"I love meeting girls in a pub. Guaranteed Beer Girl."