Bag a drink (4)

I believe the answer is:

sack

I believe this clue is a double definition.

'bag' is the first definition.
(both can mean a container)

'a drink' is the second definition.
(sack is a kind of drink)

(Other definitions for sack that I've seen before include "A bag for Falstaff's drink" , "Dismiss (from a job)" , "See 12" , "Fire - old Spanish wine" , "Big, coarse bag" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app