It's a revolutionary wine (4)

I believe the answer is:

asti

I'm a little stuck... Click here to teach me more about this clue!

'wine' is the definition.
(Italian wine)

I don't understand how the remainder of the clue works.

(Other definitions for asti that I've seen before include "- spumante, It. wine" , "White wine named after a town in Piedmont" , "It's a (anag) - wine" , "Capital of a north-west Italian province, known for its sparking wine" , "Sparkling white wine" .)

Want a hint initially instead of a full solution? Install my app