Fill a water bath canner, 3/4 full with water, and bring to a to a rolling boil.

While you are waiting for your water to boil, rinse your canning jars and screw bands and then place them in a bath of hot water. Place canning lids in saucepan and let stand in hot water until ready to use.

Draining well before filling.

Measure 6 cups crushed raspberries and pour into 6- or 8-qt. sauce pot.

Stir pectin into the crushed berries and add butter to reduce foaming. Bring raspberry mixture to full rolling boil {a boil that doesn’t stop bubbling when stirred} over high heat, stirring constantly.

Stir in sugar. Return to full rolling boil and boil exactly 4 minutes, stirring constantly. Remove from heat and then skim off any foam with metal spoon.

Ladle immediately into prepared canning jars, filling jam to within 1/8 inch of the top of the jar. Wipe jar rims and threads.

Cover with two-piece lids. Screw bands on. Place jars on elevated rack in canner, then lower the rack into canner making sure to cover the jars with at least 2 inches of water.

Cover, then bring water to gentle boil. Process 10 minutes.

Remove jars and place upright on a towel to cool completely. After jars have cooled, check seals by pressing middles of lids with finger.  If lids spring back, lids are not sealed and refrigeration is necessary.

After 24 hours remove the bands and store jam in a cool dark place.