Sterilize 8 half-pint canning jars in simmering water for 10 minutes.

Score an ‘X’ on the bottom of fresh peaches and blanch in boiling water for 30 seconds, then transfer to an ice bath. Peel, crush, and measure out 4 cups.

Measure 5.5 cups of granulated sugar and set aside.

In a large pot, combine crushed peaches, lemon juice, and powdered pectin. Stir well. Add butter if using.

Bring mixture to a full rolling boil over medium-high heat, stirring constantly. Add sugar all at once and boil hard for 1 minute until fully dissolved.

Skim foam from the top of the jam mixture.

Ladle hot jam into sterilized jars, filling to 0.25 inches from the top. Secure lids tightly.

Process jars in a boiling water bath for 10 minutes to ensure preservation.

Remove jars and let cool on a towel for 5 minutes, then undisturbed for 12 to 24 hours.

Check seals by pressing down in the center of each lid. Refrigerate unsealed jars.