Set the oven on the lowest setting.

Sterilize jars, lids, and tops. Place in the warm oven.

Warmed sugar --- Sugar will dissolve quickly in the fruit mixture if it is warmed first.

Add the sugar to a heatproof container. Place the sugar in the oven for about 15 minutes.

Add the blueberries and lemon juice to a preserving pan. Simmer over medium heat, stirring occasionally, until the juices run free. Bring the mixture to a bowl, lower heat and simmer, stirring occasionally, for 15 to 20 minutes.

Add the warmed sugar to the blueberry mixture, stir with a wooden spoon until the sugar is completely dissolved.

Increase the heat, boil the mixture rapidly, without stirring for 4 - 6 minutes or until until it reaches 22FºF.

Remove the pan from heat, skim off any froth from the surface of the jam, using a long-handled metal spoon. The mixture is hot!

Immediately pour the blueberry jam into the warm sterilized jars, within 1/8" of the tops.

Seal the jars and label.