1.Tie mint in muslin. Combine berries, muslin bag and juice in large saucepan; cook over low heat, stirring occasionally, about 5 minutes or until berries are soft.
2.Add sugar; stir over high heat, without boiling, until sugar dissolves. Bring to the boil; boil, uncovered, without stirring, about 15 minutes or until jam jells when tested.
3.Discard muslin bag. Pour hot jam into hot sterilised jars; seal immediately. Label and date jars when cold.