Grain as processed makes drink (7)
I believe the answer is:
sangria
'drink' is the definition.
(type of alcoholic drink)
'grain as processed' is the wordplay.
'processed' indicates anagramming the letters.
'grain'+'as'='grainas'
'grainas' with letters rearranged gives 'SANGRIA'.
'makes' acts as a link.
(Other definitions for sangria that I've seen before include "Spanish sweetened wine drink" , "Spanish drink of wine, lemonade, fruit, etc" , "Spanish wine cocktail" , "Spanish alcoholic drink" , "Spanish drink of red wine with soda water or lemonade" .)