Bring the water to a boil, then add the hibiscus flowers and the sugar and simmer for 5 minutes. Remove the pan from the heat and let the mixture cool to room temperature. Strain through a medium-mesh sieve into a pitcher, pressing on then discarding the flowers. Taste for sweetness and chill until cold. Serve over ice.
Hibiscus Cooler keeps chilled for 1 week.
Photo: Romulo Yanes