The division bell is everything we want from a mezcal sour: tart, sweet, smoky, and lip-smackingly delicious. The recipe calls for aperol, one of the sweetest and most accessible bitter citrus apritif on the market. We have a feeling that the more bitter options campari and its ilk would probably overpower the delicate balance of flavors. The drink is named for the pink floyd album that creator phil ward listened to while devising the cocktail menu for mayahuel, a san francisco restaurant.