Wash and crush 2 quarts blackberries (should yield about 1 quart)
Put in large kettle with generous 1/2 C white rum
Slowly stir in 1 package no-sugar pectin
Bring to boil that will not stir down, stirring constantly
Add 2 C sugar, stir and cook for 3 minutes
Add 1 T butter to reduce foaming
Pack into pint jars and seal. Yield: 7 pints
The alcohol in the rum will evaporate during the cooking process, so OK for kids. The rum flavor is subtle and the jam is not overly sweet. Good on toasted English muffin bread.
I don't process jam, I just check for any mold when I open a jar. Never ran across any. I do keep it refrigerated after opening or mold will form. If you are more comfortable processing, waterbath for 10 minutes.