Ingredients
4 pounds watermelon, peeled and cut into cubes (12 cups)
1 tablespoon plus 1 1/2 teaspoons fresh lemon juice
2 1/2 teaspoons finely grated (preferably on a Microplane zester) lemongrass
1 1/2 teaspoons finely grated (preferably on a Microplane zester) fresh ginger
Coarse salt
Ice cubes
Garnish: trimmed lemongrass stalks
Preparation
Puree watermelon in a blender until smooth. Strain mixture through a fine sieve into a pitcher. Stir in lemon juice, lemongrass, ginger, and 1/8 teaspoon salt. Refrigerate until chilled, about 20 minutes.
Divide juice among 6 ice-filled glasses, and garnish with lemongrass stalks.