Blackberry Jelly - cooking recipe

Ingredients

4 3/4 c. prepared juice (about 4 qt.)
fully ripe blackberries
3 c. sugar
1 box Sure-Jell
1/2 tsp. margarine

Preparation

Crush blackberries, one layer at a time. Pour fruit into jelly bag and let juice drip. Measure sugar into separate bowl. Mix 1/4 cup sugar from measured amount to fruit pectin in a small bowl. Stir mixture into juice in saucepot. Add margarine. Bring mixture to full rolling boil over high heat, stirring constantly. Quickly, add remaining sugar. Bring to a full rolling boil and boil 1 minute, stirring constantly. Remove from heat and skim off foam with metal spoon. Ladle into jars. Wipe rims and threads. Cover with two-piece lids. Screw bands tightly. Invert jars 5 minutes, then turn upright. After jars cool, check seals. Makes about 6 cups. Jelly takes up to 1 week to set.