2 Fill canner with water and heat it up. The canner should be two-thirds full for pint and half-pint jars; half-full for quart jars. Set rack on pan rim and cover pan. Over high heat, bring water to a boil (180° to 185° for pickles); this takes 30 to 45 minutes.
3 Meanwhile, wash canning jars and rings in a dishwasher and hand-wash lids; drain. For jam only, sterilize the washed jars too: When water in canner boils, place jars on rack, lower into water, and boil for 10 minutes. Reduce heat to a simmer and keep jars in water until needed.