There's nothing like homemade blueberry jam to chase away the winter blues! When berries are in season, put up a batch of jam; you'll be glad you did when summer is but a distant memory.
Place the blueberries, lemon juice, and water in a large, nonreactive pan and bring to a boil over medium-high heat.
Add the pectin, stir to blend, and return the mixture to a boil. Slowly add the sugar, stirring constantly as you add it. Return the mixture to a boil and cook at a full boil for 1 minute, or until the jam flows off a spoon.
Fill hot sterilized jars with the hot jam to within 1/8 inch of the top rim. Make sure the rims are clean, then cover the jars cover with new, sterilized, hot lids. Immediately invert the jars for 5 minutes. This will ensure that a vacuum forms and the jars seal properly.
After 5 minutes, turn the jars right side up and let them cool on a rack overnight. Store unopened jam in a cool, dark place.