Wash and dry the plums. Pit them and cut them around the seed.
Toss the chopped plums with sugar in the cooking pot of the Instant Pot.
Turn on Saute and let is sit for 2-3 minutes stirring once in between. This time is enough for the plums to start releasing juices. Within minutes, you’ll have enough liquid in the pot. Cancel Saute.
Close the lid and set the vent to sealing position. Pressure cook on Manual or Pressure Cook for 1 minute. Wait for the pressure to release naturally for 10 minutes (NPR 10), followed by a quick release. Once the pin drops, open the lid.
Turn on Saute and let the jam reduce down to a thick spreadable consistency. Using a potato masher, break down the plums. Alternatively, blend using an immersion blender for a smoother consistency. Stir every 5-7 minutes to prevent the jam from sticking at the bottom.
The jam will continue to thicken once it cools down. Depending on the quantity and the juiciness of the plums, this can take anywhere from 20-30 minutes. Cancel Saute once the jam reaches a thick but pourable consistency and coats the back of a spoon with a thin layer of jam.
Let the jam cool down completely before adding to jars. If preserving for longer, use the canning procedures by your preferred brand. Else, store the jam in the refrigerator. I pop a few jars in the freezer and take them out as needed.
Stove Top Recipe
Wash and dry the plums. Pit them and cut them around the seed. Toss the fresh plums with sugar in a stockpot or pasta pot.
Add the plum and sugar mixture to the pot. Start on a medium-high heat and when the fruit comes to a boil, reduce the heat to medium and keep stirring every 5 minutes or so.
You can mash the fruit to your liking using a potato masher. The jam is done when it has reduced down to a jam-like consistency. For 10 cups of fruit, it takes me about 45-55 minutes, depending on how ripe the fruit is.
Quantity of Plums: 10 cups of pitted and chopped plums. It takes roughly 4 pounds plums to get that quantity, but that can vary depending on size and variety of plums.
Quantity of sugar: Depending on how sweet or tart the plums are, it can take anywhere from 5- 6.5 cups of sugar to get to the right taste. Use 5 cups to start with and add more sugar after pressure cooking, during the simmering phase.
Start with super-ripe plums as they are more juicy and sweet. This gives you a sweeter jam without adding a ton of sugar.
Use your largest and widest pot to make this jam. That's because the larger the surface area, the shorter your cook time will be.
Towards the end, the fruit splashes as it boils, I'm sure you don't want it all over your cooktop, so, using a splatter screen comes in handy with a recipe like this.