Red Plum Jam

The other day we were given red plums by a friend- it seems some of the branches broke off the tree because they were so heavy with plums.
We'll happily take them, of course, but I don't think we could eat them all before they start to turn.
Something needed to be done.
The best way to quickly dispatch a weighty gift of plums...?

Jam comes to mind.
The difference between supermarket plums and plums fresh off a tree? In taste, color, texture, and scent there's no contest.
It doesn't matter if they're bruised, it doesn't matter if they're overly juicy. In fact, it's great.
They smell wonderful! Fruity, floral, a little tangy.
Some were red as garnets inside, others with flesh a combination of red and gold.
And when the jam began to cook, the fruity perfume wafting from the pot was like no other- it's sort of intoxicating.  Someone is going to have to start marketing a red plum perfume.

Not too sweet, tartness intact (but I like it a bit tart).

So, it seems I've been making jam quite a bit. 

It's not completely intentional. It just happens.

If you happen to have plums but don't want to make jam, there are other options. Eating them fresh is an easy one.  A crostata, if you like the idea, is a fantastic option. Really ripe plums, crème anglaise, and some toasted almonds sounds pretty good, too.
Fruit desserts are always welcome in the summer.

Plums naturally contain pectin, so if you plan to make jam, there should be no problem with it jelling properly.  However, since fruit can vary so widely, there shouldn't really be a set time for when jam is finished when you don't use commercial pectin- especially when you're cooking a large quantity. It depends on how juicy the fruit is, how much the jam has to reduce before it jells, your stove...
For me, it took about 65 minutes to reach the point I was looking for. If your plums are particularly juicy, maybe this will be about right for you.

Other options that might be nice with plums:

strawberries

raspberries
orange zest
vanilla bean

a little cinnamon

some fresh ginger

Red Plum Jam
made about 4 1/2 pints (a little more than 2 L)

5 lb. (about 2.26 kg) ripe red plums
3 1/2 c (700 g) sugar
zest of 1 lemon

Quarter the plums (skin on), discarding the pits, and place the fruit to a large non-reactive pot. Add the sugar and lemon zest and stir until all the plums are coated. Leave the mixture to sit 1-2 hours, stirring occasionally so the plums release their juices.

Place a small plate in the freezer.
Heat the pot over medium and bring the mixture to a boil. Reduce the heat to a simmer and cook until the jam reaches the jelling point. While the jam cooks, skim off any foam that rises to the top. 
To check if the jam is set, remove the plate from the freezer and place a small amount of the jam on the place. Return the plate back to the freezer and let it set a few minutes before removing it again. Using a finger, nudge the jam. If it wrinkles, it should set just fine. If not, try again after the jam cooks a while longer. 
Ladle the jam into clean jars and screw the lids on (be careful, the jars will get hot).
*Process the jars of jam at this point if you would like them to last longer and be shelf stable. 
Let the jars sit at room temperature until you're able to handle them easily then place the jars in the refrigerator.
Jam should last at least a month and up to several if kept refrigerated.