1 cup water
3 cups grapefruit juice
1/2 cup campari
Mix the water and sugar together in a small pan over a low heat, bringing to boil until the sugar dissolves. Allow the simple syrup to boil for exactly 4 minutes (this will give the sorbet the best consistency). Remove from heat and cool (makes a little over 1 cup).
Combine the citrus juice and Campari and add 1 cup of the cooled syrup. Adjust to taste — want to add a tablespoon or two extra syrup if you prefer it less tart. Remember, the mixture will taste slightly sweeter in liquid form than it does when frozen.
Freeze in an ice cream machine according to manufacturer’s directions. After churning, allow sorbet to set in the freezer at least two hours.