Prepare boiling water canner. Heat jars in simmering water until ready for use. Do not boil. Wash lids in warm
soapy water and set bands aside.
Combine berries in an 8-quart saucepan. Gradually stir in pectin. 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 jam into a hot jar leaving a ¼ inch headspace. Remove air bubbles. Wipe jar rim. Center lid on jar and
apply band, adjust to fingertip tight. Place jar in boiling water canner. Repeat until all jars are filled.
Process jars 10 minutes, adjusting for altitude. Turn off heat, remove lid, let jars stand 5 minutes. Remove jars
and cool 12-24 hours. Check lids for seal, they should not flex when center is pressed.