1 (3-pound) ripe cantaloupe or other small melon, cut into large dice (about 4 cups)
3 cups cold water
2 teaspoons freshly squeezed lime juice (from about 1/2 lime)
2 teaspoons granulated sugar, plus more as needed
Look for the ripest melons available in the produce section—the riper the melons, the less sugar you’ll have to add to the recipe. A ripe melon should be fragrant, heavy for its size, and should yield slightly to pressure at the stem end.
Place the cantaloupe, 1 1/2 cups of the water, the lime juice, and measured sugar in a blender and blend on high speed until smooth, about 20 seconds.
Strain through a fine-mesh strainer set over a large pitcher or bowl, using a ladle or wooden spoon to press down on the solids (you should have about 2 cups of liquid). Discard the solids.
Add the remaining 1 1/2 cups water and stir to combine. Taste and add additional sugar as needed. Refrigerate until cold, at least 1 hour. Serve over ice.