3 c. grape juice
2 c. blackberry juice
7 c. sugar
1 box sure-gel fruit pectin

Combine juices in a sauce pan; add sure-gel fruit pectin. Bring mixture to a rolling boil over high heat, stirring constantly. Quickly add sugar, bring to full rolling boil for 1 minute, stirring constantly. Remove from heat. Put in jars. Invert jars for 5 minutes and turn right side up.