Yellow and Green Plum Jam

Our neighbor across the street gifted us a giant bag of lovely yellow and green plums from the trees in his yard. We ate some and then I looked at the giant bag and realized that I needed to figure out something else to do with them before they rotted away. Jam was the answer!

But. I struggled to find a yellow or plum jam recipe that sounded like what I imagined in my head. This led to my first ever experiment with making up my own jam recipe! My reading told me that plums have lots of natural pectin and thus adding more was not necessary (and convenient since I didn't have powered pectin at home). The ratios of sugar to fruit varied but about half the amount of sugar as fruit seemed common so that's what I did.

I halved and quartered the plums, removing the pits (the green ones were a free stone while the yellows were cling) and tossed them with the sugar (about 3c to about 6ish c of fruit) and let them sit while working. I also thinly sliced a small (like really small) apple as a backup extra pectin supply and tossed that to. I also added lemon juice from the lemon in thefridge because the recipes all said to.

Eventually I needed a break and started the jam. Fruit and sugar into a pot on the stove while sterilizing the jars in the waterbath pot. I also put some plates in the freezer as many of the recipes suggested. The fruit cooked down dramatically - reducing by more than half and turning a lovely golden color with streaks of red from the apple. I added some lemon zest and vanilla extract after tasting along the way. I did a few tests and around 30 minutes of cooking found that the jam had set up. Into jars and waterbathed for 10 minutes.

I ended up with 5 half pints and an extra bit for the fridge.

Thoughts
The jam seems a bit too sweet to my taste. Since he just dropped off another bag (this one of just green plums) I think I'll try reducing the sugar a bit to get a less sweet flavor. I'm also wondering about add-ins. Maybe ginger? The jam is firmly set - it's probably a bit overly cooked in fact.