Peel and core the pears and apples. Cut into slices. Peel and grate ginger. Combine pears, apples, grated ginger and water in a saucepan. Bring to a boil then simmer, covered for 25 minutes or until fruits are soft.
Add sugar, lemon juice and ginger juice. Cook over medium low heat, without boiling, until sugar is dissolved.
Stir to mix well then bring to a low simmering boil, uncovered, over a very low heat. Do not stir, allow to simmer gently for 25-30 minutes or until jam gels when tested.
Pour into hot sterilised jars immediately and seal when cold.