Bollinger's Special Cuvée comes first in its commitment to quality. Thus, predominantly Premier and Grand Cru wines are married in the cuvee. After each harvest, Bollinger selects some of the wines that best characterize the vintage as reserves and stores them in reserve magnum bottles under natural cork for five to fifteen years. To guarantee the quality and freshness of the "vins de réserve" over the years, a light bottle fermentation is allowed. This method is unique in Champagne. The assemblage of the Special Cuvée contains 5 - 10% "vins de réserve".