Use fully ripe berries. Wash and remove stems. Place in 6 or 8 quart boiler; cover with water and boil 5 to 10 minutes. Let cool. To extract juice, place prepared berry in dampened jelly bag or several thicknesses of cheesecloth. Let drip; when dripping gently press or squeeze bag.
Measure sugar and set aside. Measure juice and Sure Jell. Bring to a full boil over high heat, stirring constantly. At once stir in sugar, stir and bring to a full rolling boil that cannot be stirred down; boil hard for 5 minutes, stirring constantly. Remove from heat, skim off foam with large metal spoon. Immediately put into hot jars and seal.