To make blueberry preserves, bring 2 1/4 pounds of blueberries, 3 3/4 cups of sugar and the juice from 1 lemon to a simmer in a pot, and then pour it into a covered glass bowl. After chilling the mixture overnight, bring it to a boil in a pot, and stir occasionally, for up to 10 minutes. Once the blueberry preserves reach 221 degrees Fahrenheit, pour it into sterilized jars, and store the jars in a refrigerator.
Another recipe calls for pectin, blueberries, lemon juice, sugar and spices. Blend 8 cups of washed fresh blueberries in a food processor until a puree forms, and then transfer the puree to a pot along with 6 cups of sugar, 3 tablespoons of lemon juice, 2 teaspoons of grated lemon peel or lemon zest, 2 teaspoons of ground cinnamon and 1/2 teaspoon of ground nutmeg.
Bring everything to a boil, and then add two 3-ounce pouches of liquid fruit pectin. Boil the mixture for another minute before removing it from the heat, skimming off the foam and spooning it into sterilized jars. Leave 1/4 inch between the jam and the mouth of the jars, and agitate the mixture to remove any bubbles. Screw on the lids, and place the jars in a canner for 10 minutes.