Bring a large pot of water to boil and prepare canning jars.
Fill warmed jars with hot apple sauce, leaving ½ inch of headspace. Remove air bubbles by running a wooden skewer or butter knife around the inside. Wipe rim clean. Place lid on jar and finger-tighten the band (it needs to be tight enough that it keeps the lid on, but not so tight that air can't escape).
Process jars in the hot water bath for 20 minutes, adjusting up for altitude (25 minutes for 1,000-3,000 feet, 30 minutes for 3,000-6,000 feet, and 35 minutes up to 8,000 feet).
Remove jars from pot and let cool for 24 hours. Check to make sure each jar is sealed. Store for up to 1 year.