from Food in Jars, Marisa McClellan
makes approx 8 half pint jars
If you haven't canned before, this link will take you to my blog post on making plum jam, filled with step by step photos and further links to great canning sites (plus a super easy recipe for Italian plum jam).
Marisa doesn't specify what type of plums to use; whatever is in season and bursting with ripeness is the right choice. I was lucky to get sweet and sunny Shiro plums; their bright yellow added a golden glow to the jam.
8 c peeled, pitted and mashed peaches (about 4 lb)
4 c pitted and mashed Shiro plums
6 c granulated sugar
1 c ginger juice*
1. Prep your canning equipment. Clean and sterilise half pint jars by washing them in warm soapy water and rinsing thoroughly; putting them through the quick wash cycle in the dishwasher is even easier and ensures sterilization. Set aside on a clean tea towel.
2. Wash the lids and the bands. Keep the lids hot in a small pot of simmering water. Fill your canner with water, add the clean jars, and put on the stove over medium high heat.
3. Combine the fruit, sugar and ginger juice in a large pot. Attach a candy thermometer to the side of the pot and bring the jam to a simmer. Increase the heat and boil the jam briskly until it reaches 220˚F, or it passes the saucer/spoon test.
4. Drain the jars from the water bath, and pour the hot jam into the jars. Apply lids and bands, put back in water bath and bring to a boil. Process for 10 minutes, remove from water and set aside to cool thoroughly.