The recipe yield is:
1. Wash, hull and halve berries. Crush one layer at a time and measure 5 3/4 cup into a 6-quart kettle. Stir in lemon juice. Add pkg of pectin and stir thoroughly to dissolve. This will take several minutes. Stir down sides of pan and crush any remaining lumps of pectin. 2. Place pan on high heat. Bring to a boil, stirring constantly to prevent scorching. 3. Add sugar gradually, then butter, mixing well. Continue stirring and bring to a full rolling boil (a boil that cannot be stirred down). Boil hard exactly 4 minutes, stirring constantly to prevent scorching. 4. Remove jam from heat. Skim foam from top. 5. Pour into hot, sterilized jars, wipe top and threads of jar. Apply hot lid and screw band. Twist screw band down tight. Process in boiling water bath 5 minutes. Start counting time when water comes to a boil.