Current beer available in bar? (7)
I believe the answer is:
draught
'current' is the definition.
(a draught is a current of air)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for draught that I've seen before include "ship needs so much water?" , "(Of beer) sold from the cask" , "Cool air current indoors" , "air moving" , "unwelcome arrival under the door?" .)