Prepare raspberries – clean, cook, juice.
Prepare boiling water canner. Heat jars and lids in simmering water until ready for use. Do not boil. Set bands aside. Measure juice and other ingredients. If you need more juice, simply add water to fruit pulp and extract.
Pour prepared juice into a 6-or 8-quart saucepan. Gradually stir in pectin. Add up to 1/2 tsp. butter or margarine to reduce foaming, if desired. Bring mixture to a full rolling boil that cannot be stirred down, over high heat, stirring constantly.
Add entire measure of sugar, stirring to dissolve, Return mixture to a full rolling boil. Boil hard 1 minute, stirring constantly. Remove from heat. Skim foam if necessary.
Ladle hot jelly into hot jars, leaving 1/4 inch headspace. Wipe rim. Center lid on jar. Apply band until fit is fingertip tight.
Process jars in a boiling water canner for 10 minutes, adjusting for altitude. Remove jars and cool. Check lids for seal after 24 hours. Lid should not flex up and down when center is pressed.
Yields 6 cups of jelly.