Blackberry Jelly - cooking recipe

Ingredients

4 c. blackberry juice (about 3 qt. boxes berries)
7 1/2 c. sugar
1 bottle liquid pectin

Preparation

Sort and wash ripe berries; remove stems or caps.
Crush berries and extract juice.
Measure juice in kettle; stir in sugar.
Place on high heat and stirring constantly, bring quickly to rolling boil that cannot be stirred down.