I made this a few days ago, and think it's a wonderful recipe, but it needs to be re-written for it to work well. I used 6 oz of Blackberry Fusion Jello, and the flavor is awesome, but the jam is too thick. I believe 3 oz would work much better. I forgot to mash the berries before I added them to the rhubarb and sugar in the pot, so I couldn't get them broken down very much. I brought the mixture to a rolling boil for 1 minute, then added the jello, returned to a boil, and put in jars. A lot of the mulberry seeds got stuck to the pan, and that was helpful to cut back on the number of them. They also float to the top of the jam in the jar, but they don't bother me too much as I'm eating it. They aren't as hard as raspberry seeds so you can pretty much ignore them. According to my county extension office, this jam cannot be water bath canned safely because gelatin is a protein. This is a great refrigerator/freezer jam. The recipe yielded around 40-45 ounces.