- In a large heavy saucepan, combine blueberries, rhubarb, lemon rind and juice and water.
- Bring to a boil, stirring frequently, reduce heat and simmer, very gently, for 10 minutes.
- Stir in Sugar; increase heat to high and boil vigorously until jam reaches setting point.
- 218 - 220F or 103 - 104C, 10 to 15 minutes, stirring frequently.
- Remove from heat, skim off foam and stir for 3 - 5 minutes to suspend fruit evenly throughout jam.
- Fill sterilized jars and seal.
- Makes about 4 pint jars or 8 - half pint jars.