50% Mondeuse/50% Altesse + Chardonnay. Méthode champenoise. Though not vintage-dated, it is always single-vintage. Most Montagnieu sparkling is mainly Chardonnay; 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.