Most Cognacs are 80 proof or 40% alcohol. Occasionally, a Cognac House will produce a higher proof Cognac. Higher proof Cognacs are generally more suited for mixing in cocktails than sipping. For example a few years back, Hennessy introduced Hennessy Black 86 proof (43%) specifically as a cocktail mixing Cognac. Louis Royer pushes it up a notch with “Force 53” a VSOP Fine Champagne Cognac that is 106 proof (53%)!
Pierre Ferrand’s Original Formula 1840 weighs in at 90 proof (45%). Original Formula, however is not a johnny come lately but is a Grand Champagne Cognac based on an original “three star” designated Cognac produced (the equivalent to today’s V.S. designation) back in 1840. The original bottle of Pinet Castillion Cognac on which Original Formula is based was blended and distilled for use as a mixer in cocktails.