50% Mondeuse/50% Altesse + Chardonnay. Though not vintage-dated, Peillot's Brut is always single-vintage, methode champenoise wine. Most cru Montagnieu sparkling is Chardonnay-dominant; Peillot emphasizes local varieties Altesse & Mondeuse. Average vine age is around 30 years, with some plots of Altesse and Mondeuse up to 60 years old. Much of the Altesse is planted on rocky limestone scree on a steep slope right by the village of Montagnieu, trained individually in local traditional gobelet sur échalas style; the Mondeuse comes mainly from flatter, sandier, red clay soils downslope from town, close to the Rhône River. The different varieties are harvested by hand and vinified separately, parcel by parcel. The clusters are direct-pressed and spontaneously fermented in tank; the blending takes place in late winter. The blended wine is bottled with a liqueur di tirage and finishes fermentation in the bottle; it is disgorged and finished with a 6-gram dosage. Bugey is the AOC and Montagnieu is the village and cru.