Berry we used as a drink producer (7)
I believe the answer is:
brewery
'a drink producer' is the definition.
(I've seen this before)
'berry we used' is the wordplay.
'used' indicates an anagram.
'berry'+'we'='berrywe'
'berrywe' anagrammed gives 'BREWERY'.
'as' acts as a link.
(Other definitions for brewery that I've seen before include "Place making beer" , "local supplier" , "Source of beer" , "Beer producer" , "Where beer is made" .)