Is a 21 yr old bottle of Asti Spamante good?

A 21-year-old bottle of Asti Spumante is likely to be past its prime, as this sparkling wine is best enjoyed when it's young and fresh, typically within a few years of its vintage. Over time, it may lose its effervescence and fruity character, potentially resulting in a flat or less appealing taste. If the bottle has been stored properly, it might still be drinkable, but it may not deliver the delightful experience associated with a younger Asti Spumante.