Recipe is from Karo Sweet and simple recipe Cookbook 1992. Notes on No Cook Jams: Since no cook jams require no heat processing, they are more brightly colored, fruitier and fresher tasting than cooked fruit jams. Use firm, fully ripe, unblemished fruit. Chop quickly in small quantities using a blender, food processor or grinder. (to prevent some fruits like peaches, pears, and apricots from darkening, add lemon juice.) Corn syrup enhances fresh fruit flavor and blend easily. Freezer jams can be made with any fruit except fresh pineapple. Blueberries are best used as a secondary fruit in a combination.