Homemade Watermelon Sherbet. I do not have an ice cream maker so I gonna try this method, first pour your ice cream mixture into a gallon sized bag, and freeze it flat till its rock solid. Then break it up roughly, and put it in a food processor or blender till its very smooth, which means you've broken up the ice crystals. Then put it in a container of ur choice and after a few more hours of freezing its done! The texture of this method is very smooth.