3 cups sugar
2 - 1/2 envelopes Knox powdered pectin (2 envelopes + 1 tsp)
- Wash and chop plums coarsely. Put in 6 quart pot with 1 1/2 cup water. Cook over medium heat about 15 minutes until plums fall apart and are lumpy. Cool then fish out pits.
- Add sugar, stir and taste. (Add up to 1 cup more sugar if you wish.) Remove 3/4 cup of jam to a measuring cup. Add pectin and stir. Add 3/4 cup boiling water. Stir then add to jam.
- Bring to a boil while stirring constantly. After 1 minute remove the pot from the heat and do a spoon test and cold saucer test as described below. If too soft - put pot back on heat and repeat tests every 1 minute until ready. (I add the pectin, bring the jam to a boil and boil 4 minutes. I like a soft but not runny jam.)
- Remove pot from heat and skim off foam. Place jars on tray. Ladle jam into jars. Place lids on and screw rings over. Place jars in canner and boil for 7 mins plus 1 min more for each 1,000 feet above sea level that you are at. (In Calgary, Alberta you need to boil for 11 mins). Start timing once water reaches a boil.
- Remove jars to dishtowel covered tray and let sit 12-24 hours. After 12 hours check lids. If any lids are not sunken in then the jar is not sealed. Unsealed jars must be placed in the refrigerator and used first. Put other jars away in dark place until you want them.
- Makes 9 - 125 ml jars or 4 - 250 ml jars
Dip the spoon into the jam and lift out. Tilt spoon to side and watch how the jam drips off. If it forms two drops that come together to form a sheet that falls from the spoon it is ready.