Make beer (4)
I believe the answer is:
brew
'make beer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for brew that I've seen before include "Ferment, concoct" , "Make beer by boiling and fermentation" , "Ferment rather than distil" , "Make (tea/coffee)" , "Cup of tea (informal)" .)