Chardonnay/Pinot Noir blend is used to make sparkling wines. About 85-90% of Champagnes and Sparkling’s are a blend of about 2/3 red grapes and 1/3 Chardonnay. A few Champagnes (less than 5%) are 100 % Chardonnay (they are called blanc de blancs); fewer yet are 100% red grapes (called blanc de noirs). Rosé Champagnes, a small category, are usually, but not always, made from a blend of white and red grapes.
The reason that most Champagnes are blends of Pinot Noir and Chardonnay is that each grape variety has strengths to contribute to the final blend: Pinot Noir adds body, structure, aroma, and a complexity of flavours. This difficult variety likes the cool climate of the region, and it grows well in the chalky limestone soil. Chardonnay, a star performer in the Champagne region, gives freshness, delicacy, elegance, and finesse. For this reason, many producers make a blanc de blancs (Chardonnay).