Watermelonade 1 (12-pound) watermelon (preferably seedless) 1/4 cup sugar, divided 4 teaspoon fresh lemon juice, divided 16 cups ice cubes, divided Cut watermelon flesh into 2-inch chunks and discard rind. Purée one fourth of watermelon in a blender with 1 Tbsp sugar, 1 tsp lemon juice, 4 cups ice, and a pinch of salt. Strain through a fine-mesh sieve into a large bowl, discarding solids. Make 3 more batches. Add sugar to taste if desired and serve over ice.