Wash, peel, and core apples; slice into ascorbic-acid water if desired, then drain.
Place apples in a large pot, add 1/2 cup water, and heat quickly until tender, stirring to prevent scorching.
Press through a sieve or food mill for smooth sauce, or leave chunk-style if preferred.
Sugar may be omitted. If used, add to taste and reheat the sauce to boiling.
Fill hot jars with hot sauce, leaving 1/2-inch headspace. Adjust lids and process using the tested schedule for method, jar size, gauge, and altitude.