01 -
Wash all canning jars. Fill the water bath canner halfway with water and set aside. Place a metal spoon in the freezer. Blanch peaches in boiling water for 30-45 seconds per batch, then transfer to an ice water bath. Remove the skins, peel, and chop peaches into medium-small chunks. Stir 1 cup of sugar into the chopped peaches to prevent browning.
02 -
Measure pectin into one bowl and the remaining 4 cups of sugar into another. Place peaches, lemon juice, and butter into a large pot over medium-high heat. Use an immersion blender or potato masher to puree to desired consistency. For chunkier jam, skip further blending.
03 -
Turn the water bath canner to high to bring water to a boil. Add pectin to the peach mixture slowly, stirring constantly. Bring to a full boil, then add the remaining sugar. Stir until mixture returns to a boil; boil for 1 minute while stirring. Use the frozen spoon to check the jam's consistency by dipping it into the pot and running your finger along the back of the spoon.
04 -
Fill pint or half-pint jars using a canning funnel, leaving 1/4" - 1/2" headspace. Clean jar rims with a damp towel. Secure lids and rings. Place jars in the water bath canner, ensuring jars are covered by at least 2" of water. Bring the water to a full boil and process jars for 10 minutes. Adjust time for altitude if necessary.
05 -
Remove jars and let cool on towels. Ensure lids seal properly by checking for a popped-down seal. Store sealed jars out of direct sunlight for up to two years. Refrigerate or reprocess any unsealed jars.