- 4 lbs plums
- 1/2 cup water
- 1/2 tsp butter (optional)
- 1 box Sure-Jell* pectin
- 8 cups sugar
- 9-10 small jars with lids and screw tops
Prepare jars and screw bands by washing, then boiling in water (this is just to make them hot and sterilized, so you can use dishwasher if you choose). Place jar lids in boiling water and let stand until ready to use. Be sure jars and lids are dry (but hot) before using.
To prepare plums, discard pits (do not peel) and finely chop plums (I used a food processor). This should make about 6 cups of mashed fruit. Place plums and 1/2 cup water in saucepan. Bring to boil. Reduce heat; cover and simmer 5 minutes.
While fruit is simmering, measure exact amount of sugar into separate bowl (REDUCING SUGAR OR USING SUGAR SUBSTITUTES WILL RESULT IN SET FAILURES - use Sure-Jell for Less or No Sugar Needed Fruit Pectin for no- or low-sugar jams).
Stir 1 box pectin into fruit in saucepot. Add 1/2 teaspoon butter or margarine to reduce foaming, if desired (this really does work!). Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly.
Stir in sugar quickly. Return to full rolling boil and boil exactly 1 minute, stirring constantly. Remove from heat. Skim off any foam.
Ladle quickly into prepared jars, filling to within 1/8 inch of tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly. (When you get to the end of the jam pot, if you don't have enough for a full jar, put what is left in a jar and refrigerate.)
Place jars on elevated rack in canner. Lower rack into canner. water must cover jars by 1-2 inches; add boiling water if needed. Cover; bring water to gentle boil. Process jams 10 minutes; jelly 5 minutes. Remove jars and place upright on a towel to cool completely. After jars cool, check seals by pressing middle of lid with finger. (If lids spring back, lid is not sealed and refrigeration is necessary.)
Let stand at room temperature for 24 hours. Store unopened jams in cool, dry, dark place up to 1 year. Refrigerate opened jams up to 3 weeks.
Recipe adapted from Sure-Jell package instructions.