Question: Grignolino, is a red Italian wine grape variety, commonly grown in the Piedmont region, Grignolino has two "Denominazione di origine controllata" (DOCs) that produce wine from it, Monferrato Casale and Asti, also known as Asti Spumante, is a sparkling white Italian wine that is produced throughout southeastern Piedmont but is particularly focused, around which two towns?
Sentence (from "Asti wine"): Since 1993 the wine has been classified as a "Denominazione di Origine Controllata e Garantita" (DOCG) and as of 2004 was Italy's largest producing appellation.
Relevant evidence: No