The full-boil stage is reached when bubbles form over the entire surface of the mixture. Jams made without added pectin or gelatin require longer cooking than those with added pectin. Cook the mixture to a temperature of 221 F. If you do not have a thermometer, cook products without pectin or gelatin until they have thickened slightly. Remember to allow for the additional thickening as the product cools. Jams made without sugar are thinner than jams made with sugar.
Jams contain fruit pulp or pieces of fruit, which tend to stick to the kettle during cooking.
Stir constantly to prevent scorching. Stir in artificial sweetener, food coloring, powdered fruit pectin, and lemon juice. Bring to a boil and boil 1 minute. Remove from heat. Continue to stir 2 minutes.