Drink beer's head, always before time (8)
I believe the answer is:
beverage
'drink' is the definition.
('beverage' can be a synonym of 'drink')
'beer's head always before time' is the wordplay.
'head' indicates taking the first letters.
'always' becomes 'ever' ('ever' can be a synonym of 'always').
'before' means one lot of letters go next to another.
'time' becomes 'age' (age is a kind of time**).
The initial letter of 'beers' is 'b'.
'b'+'ever'+'age'='BEVERAGE'
(Other definitions for beverage that I've seen before include "Prepared drink" , "Non-alcoholic drink" , "Any drink, say a beer" , "Liquid for drinking" , "Tea, say" .)