Blanc de Blancs is Champagne made exclusively from Chardonnay, most famously rooted in the chalk of the Côte des Blancs just south of Épernay. Expect racy acidity, citrus and green-apple drive, and a chalk-saline snap—though terroir and cellar choices (reserve-wine share, time on lees, dosage, malolactic, oak) create wide stylistic range. In top vintages it can age for decades, trading youthful briskness for layered notes of toast, honey, and brioche.