Bring a few inches of water to a boil in a large surface pan or pot. Invert jam jars and let them simmer for 15 minutes. The jars will sometimes pull the water up inside them. You may need to lift the jars with tongs to release the water back into the pan. Submerge the lids during the last five minutes.

In a medium saucepan over medium heat cook rhubarb and sugar about 12 minutes.

Open the pineapple and gently press the lid to pour off some of the liquid. Add pineapple and cook 3-5 minutes more. Add jello powder and mix well. Remove from heat and pour into sterilized jars. Twist lids finger tight and allow to cool.

You may hear the jars pop as they cool and seal. Store jars in the freezer until ready to serve. Keep refrigerated once open.