Grain as mashed in Spanish drink (7)
I believe the answer is:
sangria
'spanish drink' is the definition.
(I've seen this before)
'grain as mashed' is the wordplay.
'mashed' indicates anagramming the letters.
'grain'+'as'='grainas'
'grainas' is an anagram of 'SANGRIA'.
'in' acts as a link.
(Other definitions for sangria that I've seen before include "Mixed drink" , "Red wine, fruit juice, sugar and spices" , "Spanish drink of wine, lemonade, fruit, etc" , "Spanish wine/fruit drink" , "Spanish drink of red wine with soda water or lemonade" .)