Wash the jars and lids in hot, soapy water and rinse. Sterilize the jars by boiling them for 10 minutes. Keep them in the hot water until needed.
Wash and chop quince into 1" pieces. I choose not to peel the quince, but they can be peeled if you prefer a smoother texture.
Place quince in a six-quart Dutch oven. Add enough water to completely cover the quince. Bring to a boil, then simmer for 15 minutes.
Place a strainer over a bowl and drain quince, capturing the cooking liquid. Reserve two cups of liquid. This liquid will be used in the recipe instead of plain water because quince have a lot of natural pectin. This will aid in the jelling process.
Add quince to Dutch oven and add the remaining ingredients and the reserved liquid. Stir and bring to a boil over medium heat. Simmer over low heat for 30 to 40 minutes or until the syrup thickens, stirring occasionally.
Ladle hot preserves into hot jars, leaving ½ inch headspace. Remove air bubbles, wipe jar rims with a clean cloth, then add lids. Screw on collars, hand tight. Place the filled jars back into the boiling water bath and process the jars for 15 minutes. Adjust for atitude based on chart below.
Use jar-lifting tongs to remove jars from the boiling water. Make sure they seal, then store in a cool dark place for up to a year.
Notes
If you prefer the consistency of jam, use an immersion blender to get the consistency you prefer.
To avoid splatter, keep the immersion blender blade deep in the pot while using it, and make sure to turn it off before pulling it out of the preserves.
Keep in mind the quince preserves will thicken as it cools.
Quince preserves should be stored in a cool, dark location for up to a year.
If any of the jars don't seal, consume first or store in the refrigerator.