To make low-sugar quince jam, cut 7 cups of quince into slices, mix 1 cup of sugar with 1/3 cup of Stevia and boil in 2 quarts of water for five minutes. Cook the quince until it thickens, then turn off the heat, and put the mixture into jars.
Alternatively, make quince jam with no sugar by replacing sugar entirely with Splenda or natural sweetener Stevia. For every 7 cups of quince, use 3 cups of Splenda or 1/3 cup of Stevia. Another natural option is to use fruit juice, such as grape, peach or apple juice, instead of sugar or sweetener. Three cups of fruit juice sweetens 7 cups of quince, Using fruit juice as a sweetener means adding less water to the recipe. Sweeteners can be combined according to preference.
Pectin, a common ingredient in jams and jellies, is not needed to make quince jam because quince has a naturally high level of pectin. If the jam does not thicken as desired, add 1/2 packet of dry pectin to aid with the thickening process.
Once the mixture is in the jars with lids securely attached, put the jars in a boiling water bath to ensure that the lids are secure and sanitary.