A way one identifies sparkling wine (4)
I believe the answer is:
asti
'sparkling wine' is the definition.
(Asti is a type of sparkling wine)
'a way one' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'one' becomes 'i' (Roman numeral).
'a'+'st'+'i'='ASTI'
'identifies' is the link.
(Other definitions for asti that I've seen before include "It's a (anag) - wine" , "White wine named after a town in Piedmont" , "Italian wine - (then change a letter for ...)" , "town in Italy" , "Italian white wine" .)