This shockingly refreshing drink is a mainstay of kiosks in Sicily, particularly in the eastern city of Catania and the surrounding region. You could think of it as a natural Gatorade: crisp, assertively salty-tart and replenishing after a day under the intense Mediterranean sun. The magic of the drink is in the interplay between the lemon juice and salt — salt softens the lemon’s bitter sharpness into a flavor that’s almost rounded and savory. You can customize it in a few ways: Sicilian lemons are less acidic than regular ones, closer to Meyer lemons, which you should use if you can find them. A seltz also tastes great with half lemon and half lime. Sicilians would not serve this over ice, but you can feel free to do so, or to add a twist of lemon zest. Regardless, enjoy a seltz on a hot day, after a hard workout or a large meal.