I started out making a plum jam but after pitting one pound of cherry size fruit I changed to making a jelly. I was so glad I did it was not only a lot faster but I ended up with jelly i would like to give as gifts. This disastrous attempt to making a jam also worried me. http://www.flickr.com/photos/lakenvelder/4961921663/ I also came across this recipe of a BBQ sauce http://www.lizonfood.com/2009/10/wild-plum-barbeque-sauce.html that used with the left over mash. I wish I had found it sooner. You have another step to move the pits but that is after you have cooked the fruit already.I really hated putting all of the mash in the compost bin.
I put around 7 pounds of fruit in a pan and added water. I then gently boiled and mashed the fruit util they were all mushy. I then strained the fruit twice to get juice. Just let the juice drip out. If you try to force more liquid out you will end up with murky jelly.
Recipe 5 1/2 Cups plum juice
7 1/2 cups sugar
Add the juice in a pan and stir in the pectin. Bring to a boil. Stir in the sugar and bring to a boil. boil for 1 minute and then remove from the heat. You will need 8 1/2 pint canning jars. Process in a boiling bath for 10 minutes.