he mere mention of mezcal—a distillate made from agaves roasted in rock-lined earthen pits—often conjures up images of smoky cantinas and even smokier liquids being poured into dusty glasses. Not so with Sombra ($35), which means “the shadow” in Spanish and signifies the closeted role this ancient spirit has played in a world dominated by tequila, which is made from steam-cooked agaves.