Iced Hibiscus Tea

In a medium saucepan, combine the water and hibiscus flowers and bring to a boil. Simmer over moderate heat for 5 minutes. Add the sugar and cook, stirring, until dissolved. Pour the drink into a medium bowl. Fill a larger bowl with ice water and set the smaller bowl inside. Stir the drink occasionally until chilled, about 10 minutes. Strain the cooler into a pitcher and serve in tall glasses over ice.