- In a small sauce pan over medium-high heat, combine water and sugar. Bring to a boil, stirring until sugar dissolves and remove from heat. Set aside.
- In a blender or food processor, puree blackberries until smooth. Strain through a mesh sieve into another large bowl.
- Stir in sugar/water mixture and lemon juice. Refrigerate mixture until cold, about one hour.
- Process mixture in an ice cream maker according to manufacturer's instructions. Transfer sorbet to container; cover and freeze until firm, about 4 hours.