Prepare your canning setup: Fill a large pot of water for a boiling water bath and place your half pints or 8-ounce jars inside to preheat. Don’t forget your canning tongs!
Combine: In a separate large pot, combine the peach mixture (diced peaches, chopped peppers, lemon juice, and water). Bring to medium heat and simmer for 5–10 minutes, stirring occasionally.
Mash Fruit: Use a potato masher or immersion blender to break down the fruit to your desired consistency. (You can also use a food processor before heating if you prefer a smoother texture.)
Add Pectin: Stir in the powdered pectin and bring the mixture to a full rolling boil over high heat, stirring constantly.
Add the sugar: stirring until dissolved. Return to a full boil and let it bubble hard for 1–2 minutes to reach a thicker consistency. Don’t walk away—it needs to be vigorously boiling.
Test: Test the finished jam on a frozen plate to check for set. If it wrinkles when pushed, it’s ready.
Place in jars: Ladle hot jam into clean jars, leaving ¼” headspace. Wipe rims, add lids and rings, and process in a boiling water bath for 10 minutes (adjust for altitude).
Let cool: Remove jars using canning tongs and set on a towel. Cool completely at room temperature. You’ll hear that satisfying “ping” as they seal!