Step 1

Pit the plums and place them into a thick bottomed pot.

Step 2

Add in the lemon juice and cook for a few minutes, until the plums begin to release their juices.

Step 3

Add in sugar and stir.  Simmer, stirring often for about 10 minutes. If using commercially grown plums make sure you reduce the sugar by 1/3 to 1/2 to compensate for the naturally sweeter fruit.

Step 4

When the jam thickens, pour it into prepared canning jars.  At this point, the jam can either be stored in the refrigerator or processed for 10 minutes in a water bath canner.

Step 5

After a 10 minute process, turn of the heat, wait 5 more minutes and then remove the jars from the canner.

Step 6

Allow the jars to cool, and after 24 hours place any unsealed jars in the refrigerator and use within a few weeks.