My Dad and aunt Suzi have two amazing plum trees out in Trabuco Canyon. I was gifted about 6 pounds of them, and of course I made jam.
4 pounds very ripe plums, pitted and halved
4 cups sugar
Juice of one lemon
1 package or 3 tablespoons low sugar pectin.
I usually mascerate the jam the night before (or two). Basically, this makes the work easier in the long run. The fruit gets chopped and mixed with the sugar and lemon and popped in the fridge. Then, the next day the jam gets cooked down and canned.
Get your jars and pots ready to go before you start. This recipe ended up making 13 1/2 pint jars. Jars should be cleaned before use with soap and water. Warm the jars in the boiling water before use.
You will need a canning pot that is large enough to fit your jars with 2-3 inches of water covering the top of the jars during the boil, and a rack at the bottom. A smaller pot is also needed to warm the lids.
Lastly, put 3 or 4 small plates in the freezer. These will be to check the set of the jam.
Feel free to halve or quarter this recipe for smaller batches.
The next day, add the jam to your jam pot, or any large pot. It will need to have plenty of room to bubble up, so go big. Also, at this point, start your canning pot boiling.
The jam will start to foam up and cook down. This will probably take 20-30 minutes. When the foam has subsided, get ready to add the pectin. The finished jam will look more like this:
Then, add the pectin and follow the directions on the box. I used the Ball low sugar bulk pectin. The jam comes to a rolling boil and boils for one minute. Then the heat is turned off. Add your empty jars to the canning pot to warm, and turn on your lid pan to warm as well.
At this point a plate test can be done to make sure the jam has set correctly. With pectin, it most likely will, but you want to make sure to get a good texture. Put a dab of hot jam on one of the frozen plates and put back in the freezer for one minute. Then, run your finger over the top of the jam. If the jam wrinkles to the touch, it is set.
Hopefully, your water has boiled by now. Remove the jars and using a jar filler, ladel the hot jam into the jars.
Leave 1/2 inch headspace at the top of the jar, and wipe the top edge with a clean cloth. This allows the jam to expand and the vacuum to be created. Pull the lids out on at a time and place on Screw on the rings, finger tight. Not too hard so the air can escape. Place the jars with a jar lifter into the boiling water. Boil for 10 minutes. Remove without tipping and place on a towel to cool for 24 hours. Label and check the seal the next day. The lid should have popped and
should appear concave. Pressing on the top should not make any noise.
You made jam! I’m so proud of you.