Brew of beer good for an animal (6)
I believe the answer is:
reebok
'an animal' is the definition.
(I've seen this before)
'brew of beer good' is the wordplay.
'brew of' is an anagram indicator (I've seen this in other clues).
'good' becomes 'ok'.
'beer' with letters rearranged gives 'reeb'.
'reeb'+'ok'='REEBOK'
'for' is the link.
(Other definitions for reebok that I've seen before include "African runner" , "South African antelope (E, not H)" , "Antelope of southern Africa" , "South African animal" .)