R. H. Coutier Grand Cru Pierre Aux Larrons Blanc de Blancs Brut Nature 2015

Chardonnay planted in 1948 from Ambonnay's grand cru hillsides, bottled with zero dosage—this is stark, uncompromising stuff. Crushed chalk, lemon pith, white pepper and a briny oyster-shell edge cut through the bone-dry frame. Fine bubbles carry the tension without softening it; the acidity is almost austere, the finish long and flinty. Give it time—three to five more years in the cellar will let this open up considerably.