Select fresh and ripe blueberries that are uniform in color.
Sterilize the canning jars in boiling water for 10 minutes. Soften the lids in a pot of hot water.
Place the blueberries in a colander. Rinse them with cool water to remove dirt. Remove any stems and leaves.
Add 6 cups of water to 3 cups of granulated sugar in a sauce pot. Place the mixture over medium heat to dissolve the sugar, and then remove the pot from the stove top. Allow the sugar mixture to cool completely.
Add 2 tbsp. of fresh lemon juice to a quart-sized jar. Fill the canning jars with the blueberries. Pour the sugar water into the jars and leave 1/2 inch of headspace. Wipe the rims of the jars to remove any spills.
Place the lids on the canning jars. Secure the lids with the screw rings.
Prepare the water bath canner by filling it halfway. Bring the water to a boil. Place the canning jars in the water bath canner and ensure that at least 2 inches of water sits above the jars. Secure the lid on the canner.
Process the canning jars; according to pickyourown.org, you need to process the jars for 20 minutes in altitudes of 0 to 1,000 feet; for 25 minutes for altitudes between 1,001 and 3,000 feet; 30 minutes for between 3,001 and 6,000 feet; and 35 minutes for altitudes above 6,000 feet.
Remove the blueberries from the water bath canner with jar tongs. Place them on a flat surface. Avoid letting the canning jars touch each other, and set them away from drafts. Let the canning jars cool overnight.
Press down on the center of the canning jar lid with your finger. If the lid appears to pop up and down, then it did not seal properly. Place the unsealed jars in the refrigerator and use within two or three days; store the processed jars in a cool, dry location. The processed blueberries will last for 18 months.
Select fresh blueberries that are plump and uniform in color.
Drain the blueberries in a colander. Rinse the blueberries just before you plan to use them; avoid rinsing the blueberries until then, because it will make the skins tough. .
Spread the blueberries in a single layer on a pan. Use a pan with a lip or ridge to prevent them from rolling off.
Place the pan in the freezer for one to two hours. Then remove the blueberries from the freezer and pack them into freezer bags. Remove as much air as possible, and write the date on the bags. Use the blueberries within 12 months.
Thaw the blueberries in the refrigerator overnight or on the counter top for one to two hours. Rinse the blueberries off under cool water before you use them. You can add frozen blueberries to recipes, but it may increase the cooking time.