Preparation Bring rhubarb, cold water, sugar, and ginger to a simmer in a 4- to 5-quart pot over moderate heat, uncovered, stirring once or twice, then simmer 1 minute. Remove from heat and let steep, uncovered, 1 hour. Pour mixture through a large fine-mesh sieve into a large bowl, gently stirring but not pressing on solids (discard solids; you will have about 6 cups syrup). Chill syrup completely, about 45 minutes. Serve syrup in glasses over ice with a splash of sparkling water. Cooks' notes:·Syrup can be made 3 days ahead and chilled, covered. Add sparkling water just before serving. ·Syrup keeps, frozen, 3 months.
Preparation Bring rhubarb, cold water, sugar, and ginger to a simmer in a 4- to 5-quart pot over moderate heat, uncovered, stirring once or twice, then simmer 1 minute. Remove from heat and let steep, uncovered, 1 hour. Pour mixture through a large fine-mesh sieve into a large bowl, gently stirring but not pressing on solids (discard solids; you will have about 6 cups syrup). Chill syrup completely, about 45 minutes. Serve syrup in glasses over ice with a splash of sparkling water. Cooks' notes:·Syrup can be made 3 days ahead and chilled, covered. Add sparkling water just before serving. ·Syrup keeps, frozen, 3 months.