Bring a boiling-water canner, half full with water, to simmer. Wash jars and screw bands in hot soapy water; rinse with warm water. Pour boiling water over flat lids in saucepan off the heat. Let stand in hot water until ready to use. Drain well before filling.
Pit unpeeled plums. Finely chop or grind fruit. Place fruit in saucepan; add the Riesling. Bring to boil. Reduce heat to low; cover and simmer 5 min. Measure exactly 4-1/2 cups prepared fruit into 6- or 8-qt. saucepot.
Stir sugar into the prepared fruit in the saucepot. Add butter to reduce foaming. Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly. Stir in pectin. Return to full rolling boil and boil exactly 1 min., stirring constantly.** Remove from heat. Skim off any foam with metal spoon.
Laddle immediately into prepared jars, filling to within 1/4 inch of tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly. Place jars on elevated rack in canner. Lower rack into canner. (Water must cover jars by 1 to 2 inches. Add boiling water, if necessary.) Cover; bring water to gentle boil. Process 10 min. Remove jars and place upright on towel to cool completely. After jars cool, check seals by pressing middles of lids with finger. (If lids spring back, lids are not sealed and refrigeration is necessary.)
[recipe]Kara's notes: * I don't 'chop finely'... I slice a bit thicker than that, like just under a quarter inch. I like bigger pieces of fruit to bite into. Cut the fruit to your liking. ** I boil the mixture after the pectin is added until the spoon drip test works. ----> dip a round spoon into the mixture, remove it and hold it over the pot on its side; if two droplets of jam form on the ends and come together to form one drop in the middle of the edge and then drop into the pot, it's ready to go. If the droplets that form on the ends of the spoon just drop individually back into the pot, it's not yet there. Like wise, If the jam doesn't move on your spoon, it's gone too far. Better to under do it, and apply heat a second time than to over process it. I hope you enjoy this recipe. It's really one of my favorite things to make and it's kind of an event every summer since the fruit is only available for a narrow window of time. Food traditions are good 🙂
Don't Miss Out!
get all my latest recipes, how-to's, & shenanigans!