Hey! Making good on my promise!
This is actually the EASY part - and I actually don't have many pictures to go along with it (Oops!)
So for this step, you start with the plum juice you made earlier.  Give it a taste and, well, this part is a Judgement Call.  See, the juice will be pretty tart, so we'll be throwing in a lot more sweetener than I'm accustomed to using.  What you want to figure out is kinda/sorta the "depth" of the flavor and color.
If it's too watery/weak, you're gonna want to simmer it down to a lesser quantity which means more flavor.  Makes sense?
Honestly, I don't think I can give you a specific, fancy-scientifical, 100% accurate gauge to work with.  But here's what I ended up with:
- 1st batch: 5lbs fruit + I-don't-remember how much water, ended up at 12 cups of weak/watery juice. 
I simmered it down by 1/3 to roughly 8 cups (2 batches of jelly). 
- 2nd and 3rd batches 5lbs fruit + 10 cups water (each - then I combined 'em).  I ended up with a total of 17+ (ish) cups of more-condensed juice.
Simmered it down by appx 1/4 to end up with roughly 14-16 cups (3 batches of jelly) - I'm thinkin' the roughly-optimal ratio would end up being 5 lbs fruit, 10 cups water, then simmer down to ~8 cups = ~2 batches of jelly.
 
So yeah.  Kind of a Judgement Call, right?  I think - to keep it simple - I'm gonna go with the 2nd batch's numbers with the caveat that YMMV.  It's merely a guideline!
QT's Low-Sugar Plum Jelly - Made in TWO batches
The quantities listed below are for ONE batch of jam
Yield 8(ish) half-pint jars of jam (each batch is appx 4 half-pints - give or take!)
Yield 8(ish) half-pint jars of jam (each batch is appx 4 half-pints - give or take!)
Ingredients:
- 4 cups of already simmered-down/condensed plum juice
 - 2 cups granulated sugar
 - 2 cups granulated Splenda (or whatever sweetener you choose - I tend to think that Stevia might be too bitter, but that's just me)
 - 1 TBS lemon juice
 - 5 TBS Low/No-Sugar Pectin (I use this)
 
Instructions:
- Heat the plum and lemon juices in a dutch oven til it reaches a light boil/simmer
 - Stir in the Splenda (helps to use a whisk, actually - so it doesn't clump)
 - Mix the sugar and Pectin together with a fork in a dry bowl.
 - Slowly add the sugar + pectin to the juices, stirring all the while (again, we don't want clumps)
 - Increase heat to High or Medium-High, stirring constantly
 - Bring it to a rapid boil, stir-stir-stir (and keep a close watch on your temp - it will try to boil-over!). Boil hard for one full minute, stirring constantly, and remove from heat.
 - Check for "set" (spoonful of jelly on a spoon, in the fridge for a minute or two).
 - Remove the bubbly scummy stuff from the top (I set it aside to mix with plain yogurt - yum!)
 - Transfer to hot, sterilized canning jars. Wipe the rims, apply the lids.
 - Process in a water-bath for 10 minutes
 - Leave jars undisturbed for 24 hours. Check the seals (lids that pop up and down in the center are not sealed - put those in the fridge and use them first).
 
It really is delicious!  I used a lot more sweetener in this than I normally do - but it still managed to retain it's fruitiness.  SUPER pleased with this recipe!
And see how it gleams?!
Sparkling like a ruby in the afternoon sun!
Final update 7/7/2015: I used the very-last of the plums to make one more big batch o' jelly.  Did the 5lbs to 10 cups ratio.  I actually ended up with just-shy of 8 cups of juice - so I didn't need to cook it down any further.  I suspect much has to do with the ripeness of the fruit (and this fruit was super-ripe - almost over-ripe!). 
I ended up making 2 batches of jam (appx 3-1/2 cups juice, 3-1/2c Splenda/Sugar, 1T Lemon juice, 5T Pectin), and I ended up with 10 half-pints of jelly.
This definitely ain't a science!
I ended up making 2 batches of jam (appx 3-1/2 cups juice, 3-1/2c Splenda/Sugar, 1T Lemon juice, 5T Pectin), and I ended up with 10 half-pints of jelly.
This definitely ain't a science!








