Blackberry Jelly - cooking recipe

Ingredients

almost 4 c. blackberry juice
5 c. sugar
1 box pectin
1 Tbsp. butter

Preparation

Measure out sugar and set aside.
Measure juice and put into dishpan.
Add pectin and butter.
Bring to boil, stirring frequently.
Add sugar, stirring frequently, and bring to a rolling boil.
Boil for 1 minute.
Skim off foam, if necessary.
Add to hot, sterilized jars.
Wipe rims of jars after adding liquid; place flats on and screw on lids tightly.
Invert jars for 30 minutes and then turn upright, making sure jars are not touching and are not in a draft.