1. Combine sugar and 3/4 cup water in a small saucepan over medium-high heat. Cook 2 minutes or until sugar dissolves, stirring constantly. Remove from heat; cool completely.
2. Combine sugar mixture, juices, Chambord, vodka, and food coloring, if desired, in a large bowl; stir well. Pour mixture into the freezer can of an ice-cream freezer; freeze according to manufacturer's instructions. Spoon sorbet into a freezer-safe container; cover and freeze 8 hours or overnight.