Knock back the German wine (3)
I believe the answer is:
red
'wine' is the definition.
(red is a type of wine)
'knock back the german' is the wordplay.
'knock back' is a reversal indicator.
'the german' becomes 'der' ('the' in German).
'der' backwards is 'RED'.
(Other definitions for red that I've seen before include "See it and become angry" , "Colour of communism" , "- Cross; - carpet" , "Warning light colour" , "The colour of the former Russian army" .)