Something’s out there. Lurking around the shadow-laden Oaxacan fields is a sensational spirit that showcases the earthy taste of agave with a devilishly roasted, smoky edge, and it’s ready to pounce during your upcoming month of thrilling, chilling cocktail glass–filling. Mezcal’s greatest asset, besides its irresistible flavor, is how seamlessly it’s woven into the cultural…