Prepare Jars: Examine all jars for cracks or chips and discard any damaged jars. Wash jars in hot soapy water, rinse thoroughly, and keep hot in a 180°F oven or hot water until ready to fill.
Heat Lids: Place new canning lids in a small saucepan, cover with hot water at 180°F, and keep hot until ready to use. Do not boil lids as this may damage the sealing compound. Wash rings in hot soapy water.
Prepare Canner: Fill your boiling water bath canner with enough water to cover jars by 1-2 inches when submerged. Begin heating water to a rolling boil while preparing applesauce.
Prepare Apples: Wash apples thoroughly and remove stems and blossom ends. Core apples and cut into quarters or eighths. Peeling is optional but leaving peels on adds nutrition and natural color to the finished applesauce.
Cook Apples: Place prepared apples in a large heavy-bottomed pot with just enough water to prevent sticking, usually 1/2 to 1 cup depending on apple juiciness. Cook over medium heat, stirring frequently, until apples are completely tender and breaking down, approximately 15-20 minutes.
Process to Sauce: Using a food mill for smoothest texture, food processor for medium texture, or immersion blender for chunky texture, process cooked apples to your desired consistency. Add bottled lemon juice or ascorbic acid if desired for color preservation.
Heat Applesauce: Return processed applesauce to pot and heat to 190°F, stirring constantly to prevent scorching. Maintain this temperature throughout the filling process to ensure safe canning temperatures.
Fill Jars: Using a ladle and wide-mouth funnel, fill hot jars with hot applesauce, leaving exactly 1/2 inch headspace. Remove air bubbles by running a plastic tool around the inside of each jar, adjusting headspace as needed.
Seal Jars: Wipe jar rims clean with a damp paper towel to remove any applesauce residue. Center hot lids on jars and apply rings finger-tight only. Using jar lifter, place filled jars on canner rack.
Process in Water Bath: Lower jars into boiling water, ensuring they are covered by 1-2 inches of water. Process pint jars for 20 minutes or quart jars for 25 minutes. Adjust processing time for altitude: add 5 minutes for 1,001-3,000 feet, add 10 minutes for 3,001-6,000 feet, add 15 minutes for above 6,000 feet. Remove jars and cool undisturbed for 12-24 hours.
