3 c. blackberries, crushed
5 1/4 c. sugar
1 box Sure-Jell fruit pectin

Measure berries into large bowl; thoroughly stir in sugar and let stand 10 minutes. Mix 3/4 cup water and Sure-Jell in small saucepan. Bring to a full boil and boil 1 minute, stirring constantly. At once, stir into fruit and continue stirring 3 minutes. Immediately put into prepared containers (freezer jars or cartons that have been scalded), leaving 1/2 inch space at top.

With a damp cloth, wipe any spills from containers. Cover at once with lids. Let stand at room temperature for 24 hours. Store jam in freezer until ready for use.