Wash and sterilise jars and lids. Place rasberries in a saucepan and stir through sugar. Leave for 1-2 hours while sugar softens the fruit.
Add juice then cook over medium heat, stirring constantly, until fruit is soft.
Remove 1/3 of fruit. Set aside. Cook remaining mixture until fruit is mostly dissolved and jam coats the back of a spoon. Divide reserved fruit between the jars then fill with jam. Allow to cool,then seal with lids.