Pour juice through a wire-mesh strainer into a bowl; press with back of spoon against sides of strainer to squeeze out 3 1/3 cups juice. Discard pulp and seeds remaining in strainer.
Combine juice, sugar, and syrup in a large saucepan. Bring to a boil; reduce heat, and simmer, uncovered, 45 minutes, stirring frequently.
Remove from heat, and skim off foam.
Let cool. Cover and store in refrigerator up to 10 days.
Serve with gingerbread or French toast or in sparkling water.
