And what about mixing drinks with an XO ("eXtra Old")? For the $100 or so you'll pay for a bottle, you'll get something blended from brandies that have spent at least six years in the barrel, with considerable amounts of ones that have spent two or three times that long. As the cocktail theorist David Embury wrote in 1948, "To mix this nectar of the gods with any other substance whatsoever-even a single drop of water—would be sacrilege, pure and simple." But what if I were to suggest you put a very small amount of superfine sugar and water in a tall glass, stir them, lightly press five or six fresh mint leaves in the resulting syrup, fill the glass with ice pounded until it's the consistency of snow, let two and a half ounces of XO trickle over that ice, stir gently until frost forms on the glass, and float a spoonful of fragrant Jamaican rum on top, to make an antebellum mint julep? The fact is, very old cognacs do something for a drink that no other spirit can. They possess all the leathery, chocolaty richness and layered complexity that prolonged rests in older, mellower oak can bring, without the overpowering woodiness that American whiskeys so often develop in their new wood casks. In a drink like the elegant brandy crusta, a drink that combines cognac with plenty of citrus, or the bright brandy snapper with its hit of raspberry liqueur, or any drink whose other ingredients complement rather than mask the cognac, those intense flavors will mingle with the rest, become approachable, without losing complexity. If that's sacrilege, I'll drink with the sinners.