An overwhelming majority of Piedmont's wines derives from native vines. Besides the noble Nebbiolo, source of Barolo, Barbaresco, Gattinara and Ghemme, which are all DOCG, Barbera ranks as the most popular vine for reds, followed by Dolcetto, which is enjoyed for its mellow, round flavors. Brachetto makes sweet, fragrant bubbly red that is DOCG as Brachetto d'Acqui. Freisa and Grignolino lead a host of local varieties in rounding out the honor roll of reds. Still, among classified wines, whites represent about a third of the volume. First comes Asti, whose DOCG applies to both sparkling Spumante and the softly bubbly Moscato d'Asti. With an average annual output of nearly 60 million liters, the Asti appellation ranks second in volume to Chianti among Italy's classified wines.