2 ¾ cups sugar
25 ounces (5 cups) blueberries
2 tablespoons bottled lemon juice (not fresh-squeezed)
2 teaspoons grated lemon zest
2 tablespoons Sure-Jell for Less or No Sugar Needed Recipes (or other low-sugar pectin)
Freshly picked ripe-yet-firm blueberries are best for making jam! Please note: For safety reasons, be sure to use bottled lemon juice, not fresh-squeezed juice, in this recipe.
2. Combine ¼ cup sugar and Sure-Jell in a bowl. Bring blueberries, lemon juice, and lemon zest to simmer in Dutch oven over medium-high heat. Reduce heat to medium-low and simmer, stirring occasionally, until blueberries have softened and released their juice, about 5 minutes.
3. Bring mixture to boil over high heat. Whisk in Sure-Jell mixture and bring to boil. Whisk in remaining 2 1/2 cups sugar and bring to a vigorous boil. Once boiling, cook for 1 minute, whisking constantly. Remove pot from heat and skim any foam from the surface of the jam using a spoon.
4. Place a dish towel flat on the counter. Using a jar lifter, remove jars from the pot, draining water back into the pot. Place jars upside down on a towel and let dry for 1 minute. Using funnel and ladle, portion hot jam into hot jars, leaving ¼ inch headspace at the top of the jars. Slide a wooden skewer along the inside edge of the jar and drag upward to remove air bubbles.
5. For short-term storage: Let jam cool to room temperature, cover, and refrigerate until jam is set, 12 to 24 hours. (Jam can be refrigerated for up to 2 months.)
For long-term storage: While jars are hot, wipe rims clean, add lids, and screw on rings until fingertip-tight; do not over-tighten. Return the pot of water with a canning rack to boil. Lower jars into water, cover, bring water back to boil, then start the timer. Cooking time will depend on your altitude: Boil 10 minutes, then turn off heat and let jars sit in the pot for 5 minutes. Remove jars from pot; let cool for 24 hours. Remove rings, check seal, and clean rims. (Sealed jars can be stored for up to 1 year.)