Our plum tree drops a few fruits every day. Instead of letting these go to waste, we pick them up, rinse them off, cut off any smashed bit, and stick them in the freezer for jam making. When we got three gallon-sized bags filled, I decided it was time to make jam.
I added eight ounces of water, to keep the defrosting plums from sticking to the pot, and slowly cooked them. When the plums were suitably pulpy, I started digging out the pits. I chucked them in the vintage "chinoise" that I bought at the White Elephant Sale at the Oakland Museum a few years back, and smooshed out as much pulp as I could. The skins pretty much de-materialized, in the cooking process.
I added sugar to taste, in my case about four and a half cups. (That seems like a lot, but this is tart jam.) And then I added half a pouch of pectin. Once again, I didn't get great set. Either I let the pectin cook too long, or I mis-read the "set test" of sticking some jam on a frozen plate. In any case, this jam is a wee bit sloppy.
But who cares if the jam is a tad runny? It's insanely delicious.