Only the years with the best growing conditions will warrant a vintage release. In France, Vintage Champagne is a blend of wines from a particular year and it must be composed of at least 85% of the grapes from vintage year, is left to the individual houses themselves to declare. Vintage Champagne must be a minimum of 39 months old before it is sold with the best houses aging far beyond the legal requirements. Under Champagne wine regulations, houses that make both vintage and non-vintage wines are allowed to use no more than 80% of the total vintage's harvest for the production of vintage Champagne. This allows at least 20% of the harvest from favorable vintages to be reserved for use in non-vintage Champagne. The best marques of classic vintages are extremely cellar worthy and will evolve beautifully with additional bottle age.