Hair-of-the-Dog Pineapple Soda

Put frozen pineapple juice in a large pitcher. Add 2 to 3 tbsp. seltzer; whisk to blend. Gently stir in 3 cups seltzer and plop in some ice. Serve with bottles of whatever was imbibed the night before, so each person can add to taste—or not at all.

Note: Nutritional analysis is per drink without alcohol.