Put blueberries in blender in small amounts (about 1/4 pound at a time), adding enough water each time to let the blender work well (about 1/4-1/2 cup), and about 1/4 cup of corn syrup to up to a total of 1 cup.
Freeze in the freezer, stirring every 1/2 hour-1 hour, as I don't have a machine.
After it's frozen and ready to serve (about 3 hours later), I add 1-3 tablespoons of sugar to the top of the sorbet and then mix that around.
Adding the sugar on top at the end makes it a little grainy - but it's a little like having sugar on top of fresh berries.
Corn Substitutions: Corn is a common ingredient in products. Starch, modified food starch, dextrin and maltodextrin can be from corn. Consult with your physician to find out which corn derivatives you need to avoid. Many corn-free options are available in the US. Find out more about corn substitutions.