Wash berries; remove any stems and rotten berries. Drain.
Pour berries into a large, stainless steel stock pot, and heat over low just to warm. Crush berries to extract juice.
Ladle berries and juice into a jelly bag. Hang the bag to drain over a bowl for several hours, squeezing as necessary to remove the juices.
Measure the juice. You need 4 cups. Add water or another fruit juice as necessary to fill to this exact amount (you shouldn’t have to add much). Pour the juice back into the large stock pot.
Measure 5 1/2 c. sugar into a separate bowl. Do not reduce. If you want a low-sugar jelly, you’ll need to use a low-sugar pectin (which will have a different set of instructions).
Add 1 box of powdered pectin to the juice in the pot, and bring to a full rolling boil over high heat.
Quickly pour in the sugar, and stir. Return to a full rolling boil, and allow to boil for 1 minute exactly. Remove from heat.
Ladle hot liquid into hot, sterilized jars, leaving 1/8″ headspace.
Wipe rims of jars with a wet rag, to remove any sticky residue.
Affix a previously simmered lid and ring.
Process in a boiling water bath canner for 5 min.
Remove from canner, and allow to cool on the counter for 18-24 hours before testing the seals on the lids.