Acid Acid is needed both for gel formation and flavor. The acid content varies among fruits and is higher in underripe fruits. When fruits are low in acid, lemon juice or citric acid may be added. Added acid is always required with certain types of commercial pectins. Sugar Sugar must be present in the proper proportions with pectin and acid to make a good gel.
Sugar also prevents the growth of microorganisms in the product and contributes to the taste.
Never change the amount of sugar in a recipe. Sweeteners such as brown sugar, sorghum, and molasses are not recommended because their flavors overpower the fruit and their sweetnesses vary. Extra fine sugar or sugar blends with dextrose, fructose, or other sweetener added should not be used. You can replace part but not all of the sugar with light corn syrup or light, mild honey. For best results, use tested recipes that specify honey or corn syrup.