1. Wash and dry the blueberries and set aside. Sterilize 2 quart jars along with the lids in boiling water or in a dishwasher run without soap.

2. In a large stockpot bring the water, sugar, corn starch and lemon juice and to a boil.

3. Pour in the blueberries very carefully and bring the mixture back to a boil, stirring continuously with a long spoon. Keep stirring for about 5 minutes while the berries release their juices and the mixture thickens, becoming blue and glossy.

4. Set a funnel over a quart jar and ladle in the blueberry mixture, leaving about 1″ of room at the top. Repeat with second quart jar.

5. Placed the sterilized lids on the jar and seal them with the rims, only tightening the ring as much as you can with your own hand. Do not force it.

6. Place the jars in a pot of boiling water standing on end. Make sure the water covers the tops of the jars. Boil for 30 minutes, starting the timing when the mixture has returned to a boil after the jars have been added.

7. Remove jars and place in a cool, dry place on a kitchen towel. Allow to cool naturally for a few hours. Store jars for the long term in a cool, dry place until using.