Sep 27 2012

Adventures in Canning: Plum Jam

On Sunday, our neighbors invited us over to pick plums from their Italian plum tree. The tree was bursting with so much fruit that even these seasoned gardeners seemed surprised. They commented that they'd never seen the tree so laden with fruit. We gladly ventured over with a large bowl and picked four pounds worth in 5 minutes, with Justin knocking a few errant plums on my head as I held his ladder!

If you are a prune hater (or a prune juice hater), then you can blame this variety: prunes are dried Italian plums. As the pictures reveal, these plums are deep purple, with a powdery-filmed skin. Cutting one in half reveals a yellow or green color, depending on how the light falls on the fruit.

I immediately knew I wanted to turn these plums into a rich plum jam, and so I turned to my always reliable copy of The Blue Chair Jam cookbook. I located an appealing recipe for Damson Plum Jam, and after a few minutes of research, decided that Damson and Italian are closely enough related for the recipe to work. Both are Fall varieties and both are better enjoyed cooked than raw.

If you find plums at the farmers' market, or have a neighbor with an over-producing plum tree, block out two days for this recipe. On day one, slice the plums in half and remove the pit. Add the sugar and lemon juice and let the mixture macerate overnight. On day two, prepare your jars and make the jam!

This jam foamed up much more quickly than most other jams I've made this summer. As soon as the plum mixture reached a boil, the pot was overtaken by foam. The fruits disintegrated quickly; after ten minutes the mixture resembled boiling hot lava, sending magenta pinprick splatters all over my stove and occasionally my arm.

This jam's flavor is nuanced. By adding almond extract, the jam's taste builds with each bite, from floral to savory.

Italian Plum Jam

Recipe Source: The Blue Chair Jam Cookbook


  • 4 1/2 pounds pitted and halved plums
  • 1 pound white cane sugar
  • 3 1/2 ounces lemon juice
  • a few drops of almond extract


  1. Day 1: Combine the plums with the sugar and lemon juice in a large glass bowl. cover tightly and let macerate in the refrigerator for as long as 48 hours. The goal is for the plums to release their juices.
  2. Day 2: Place several teaspoons in your freezer. You'll use these to test the jam later.
  3. Remove the plums and stir the bowl to dissolve the sugar. Transfer the entire mixture into your wide deep pan or preserving pan. Add a few drops of almond extract.
  4. Bring the mixture to a boil over high heat, stirring frequently. Boil, while stirring often, until the jam thickens, around 30 minutes. Decrease the heat as more and more moisture cooks off the jam.
  5. When the jam has thickened, test it. Put a small amount of jam onto one of your frozen teaspoons and return it to the freezer for 3 minutes. When you take out the spoon, it should feel neither warm nor hot on the bottom. Tilt the spoon: if the jam is reluctant to run and is thick, it is done. If it runs quickly, cook it for a few more minutes and then repeat the testing process again.
  6. Turn off the heat and skim off any foam that has formed. Ladle into oven sterilized jars, leaving 1/4 inch of headspace. (To sterilize your jars in the oven, heat your oven to 250 degrees before placing your jars and lids onto cookie sheets. Keep in the oven for at least 30 minutes, but longer is fine, too.)
  7. After filling your jars and securing the lids (use gloves if the jars are too hot to handle) carefully put the jars back on the cookie sheet(s) for 15 minutes.
  8. Remove the jars from the oven keeping them on their sheet(s). Put the sheet on a wire rack and cool them over night. They will seal as they cool.