Piedmont bubbly (4)
I believe the answer is:
asti
'piedmont bubbly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for asti that I've seen before include "Italian drunk" , "Italian wine - (then change a letter for ...)" , "Italian 'sparkler'" , "town in Italy" , "Italian white wine" .)