German white wine (7)
(Other definitions for hock that I've seen before include "Rhine wine -- horse joint" , "German wine -- horse's back 'ankle'" , "Deposit with a pawnbroker" , "Pawn < some ham" , "Animal joint - German white wine" .)
'german white wine' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for moselle that I've seen before include "Fr. river, department; German wine" , "Light white wine" , "French department" , "River; white wine" , "French or German white wine" .)
(Other definitions for piesporter that I've seen before include "18 [WINE]" , "White Moselle wine" .)