Whiskey grain (3)
I believe the answer is:
rye
'whiskey grain' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rye that I've seen before include "(Gypsy) gent; type of bread, whiskey" , "place in East Sussex" , "American whisky" , "Cereal - liquor" , "Hardy cereal crop" .)