Champagne spec (4)
I believe the answer is:
brut
'champagne spec' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for brut that I've seen before include "(Of sparkling wines) very dry" , "Of champagne, not sweet" , "one type of champagne" , "Unsweetened; very dry" , "Dry (of champagne)" .)