Rhubarb Jam 5 cups rhubarb, finely cut 1 (20 ounce) can crushed pineapple 3 cups granulated sugar 1 small box strawberry or raspberry gelatin Combine rhubarb, pineapple and sugar. Let stand for 3 hours or overnight. Cook slowly for 15 to 20 minutes, then add gelatin. When gelatin is dissolved, pack in clean jars and freeze or refrigerate.