Of all the experiments chef Neal Brown has conducted, whether in his kitchen laboratoire or the culinary free market, none has come as close to successful alchemy as The Libertine Liquor Bar, his shrine to the cocktail in a Washington Street storefront downtown. A shot of Scandinavian austerity, a jigger of pre-Prohibition American frontier swagger, and a dash of orange bitters dosed from eyedroppers by Brown’s exacting barkeeps, The Libertine is a study in contrasts—some logical, some forced—that all mingle, dazzlingly. Take “The Last Word,” one of several clever coinages on Brown’s drink menu. It mixes Bluecoat gin, lending its distinctly piney profile, with Luxardo maraschino and green chartreuse, haute liqueurs as opposite as stop and go. A bracing hit of lime merges these improbable comrades into a restrained elixir that cleanses the palate at the same time it sweetens it, a beguiling medicine you’re all too glad to take.