Purée persimmons and sugar together in a blender, then cook mixture in a nonreactive saucepan over medium heat, stirring constantly, for about 2 minutes. Add water slowly, continuing to stir, and cook for 3 to 4 minutes longer. Remove mixture from heat and allow to cool to room temperature. Refrigerate, covered, for at least 3 hours.
Remove mixture from refrigerator. Beat egg whites until stiff, then fold into mixture, incorporating thoroughly. Process in ice cream maker according to manufacturer’s directions.
Splash a bit of very well-chilled vodka on each portion of sorbet just before serving.
© 1992 Colman Andrews. All rights reserved.