Plums jam is easy to make; all you need is fresh, ripe plums, sugar and a bit of lemon juice. From start to finish, you will have plum jam in less than an hour.
Plums are a diverse lot; they range in color from green to yellow to red to purple to blue to black and they range in flavor from sour to very sweet. Choose your favorite for a plum jam you will love.
European plums ripen in early summer; they are fairly small and tart. Japanese plums ripen from mid- to late-summer and they are large, juicy, and sweet.
To make jam, choose plums that have a rich, deep color and skin that is firm but not taut. Just ripe plums are best for jam making—the peel will come off easily; overripe plums will be sticky and will easily split and may not make as tasty jam.
Yield 4 half-pints
- 3 pounds plums, pitted and quartered (you can use this recipe for other stone fruit as well—peaches, nectarines, apricots)
- 3 cups of sugar
- 1 tablespoon fresh lemon juice
- Rinse plums and remove pits. Finely chop or force plums through a food chopper.
- Place plums in a heavy-bottomed, 4-quart pot, stir in sugar and lemon juice and let stand for 15 minutes.
- Bring the pot to a boil over high heat—about 10 minutes–mashing the fruit with a potato masher. Stir occasionally to make sure the fruit does not stick to the bottom. Bubbles will rise to the top of the mix. You will see chunks of fruit in the mixture. Skim foam off top and lift and discard skins with a fork if desired. Cook on until the showing mixture thickens and clings to a spoon, falling off in clumps, another 10 minutes or so.
- In the meantime, scald half-pint jars in a large pot with a fitted rack. Soak lids in a pan of hot water to soften the rubber seal. Lift jars out of hot water one at a time, draining water.
- Ladle hot jam into hot jars using a wide-mouth funnel or transfer the jam to a heat-proof pitcher and pout into jars. Leave ½ inch headspace. Slide nonmetallic spatula between jam and jar to release trapped air bubbles.
- Wipe rims and threads of jar with a clean, damp cloth. Remove lid from hot water and place on jar. Screw each band down evenly and firmly until resistance is met. Place jars rack and lower into boiling-water canner until they are covered by about 1 inch of water.
- Put lid on canner. Bring water to a boil. Process ½ pints 10 minutes at a gentle but steady boil. (Start keeping time after water comes to rolling boil.)
- Turn off heat and remove canner lid. Let canner cool 5 minutes then remove jars and set them upright on a dry towel or rack. Do not retighten bands. Let jars cool 12 to 24 hours.
- After jars have cooled, check lids for a good vacuum seal: pressing the center of each lid. If center is pulled down and does not flex remove the band. If the lid does not flex and cannot lift it off, the seal is set. Wipe lid and jar with a clean, damp cloth. Label each jar. Store jam in a cool, dry, dark place.
The jam will keep for about a year. You can also use this recipe to make jam from other stone fruits as well--peaches, nectarines, apricots, cherries.