Prep peaches, stirring pieces into vinegar in pot as you go to prevent browning.
Prep and add remaining ingredients to pot.
Mix ingredients in pot, bring to a boil, then lower to a simmer uncovered for 5 to 10 minutes, until the mixture thickens to your liking, bearing in mind that it will thicken more once cold so don't try to boil it solid. Stir frequently to prevent burning.
Spoon into your choice of the following jar sizes: 125 ml ( 4 oz) jars or ¼ litre (½ US pint / 8 oz / 250 ml) jars.
Leave 2 cm ( ½ inch) headspace regardless of jar size.
Debubble, adjust headspace.
Wipe jar rims.
Put lids on.
Process in a water bath or steam canner.
Process either size jar for 15 minutes; increase time as needed for your altitude.