Wash and Stem the Blueberries: Begin with 4 cups of ripe fresh blueberries. Rinse them thoroughly under cold water, removing any dirt or debris. Remove the stems and allow the blueberries to drain in a colander.

Prepare the Jars: While the blueberries are draining, we need to prepare our jars. Sterilize 6 to 8 half-pint jars by placing them in a boiling water bath for 10 minutes.

Measure the Ingredients: In addition to the blueberries, gather 5 cups of granulated sugar, a packet of pectin, and ¼ cup of fresh lemon juice.

Mash the Blueberries: Once drained, transfer the blueberries to a large mixing bowl. Using a potato masher or fork, gently crush the berries to release their juices while leaving some chunks for texture.

Cook the Mixture: In a large saucepan over medium heat, combine the mashed blueberries with the lemon juice. Stir frequently to prevent sticking and to help release the juices. Bring this mixture to a gentle simmer for about 5 minutes.

Adding Sugar and Pectin: Gradually stir in the granulated sugar and the pectin. Continue cooking the mixture on medium-high heat while stirring constantly until it reaches a full rolling boil. Keep boiling for 1-2 minutes to activate the pectin fully.

Test for Thickness: After boiling, perform the plate test. Place a spoonful of jam on a chilled plate and let it sit for a minute. If the jam holds its shape when pushed, it’s ready for canning.

Fill the Jars: Once the jam has thickened, remove it from heat. Using a ladle, carefully fill the sterilized jars, leaving about ¼ inch of headspace at the top.

Seal the Jars: Wipe the edges of the jars with a clean cloth to ensure a good seal. Place the lids on and screw on the bands until they are fingertip tight.

Process the Jars: Process the jars in a boiling water bath for 10 minutes, ensuring that the water completely covers the jars.

Cool and Store: After processing, carefully remove the jars and let them cool. Check that all the seals are intact.