Prepare black raspberries by crushing one layer at a time with a potato masher. Place prepared black raspberries in dampened jelly bag or several layers of dampened cheesecloth. Let juice drip, undisturbed, for at least 2 hours or overnight. Note: Squeezing the jelly bag may cause jelly to be cloudy.

Prepare boiling water canner. Heat jars in simmering water until ready to use, do not boil. Wash lids in warm soapy water and set aside with bands.

Combine prepared juice with bottled lemon juice and sugar in a 6- or 8-quart saucepan. 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 frequently.

Add pectin, immediately squeezing entire contents from pouch. Continue hard boil for 1 minute, stirring constantly. Remove from heat. Skim foam if necessary.

Ladle hot Black Raspberry Jelly into hot jars leaving 1/4 inch headspace. Wipe rim. Center lid on jar. Apply band until fit is fingertip tight.

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.