Prepare jars and lids following safe canning practices.
Peel, pit and chop peaches into a large bowl. Add 2 teaspoons of Fruit Fresh or ¼ cup of lemon juice to the bowl of chopped peaches to prevent browning.
Put the sugar into a large non-reactive canning pot.
Add the peaches and ¼ cup lemon juice, and butter if using to the pot of sugar.
Stir well to moisten all of the sugar.
Turn the heat on low, stirring occasionally until the sugar starts to dissolve.
Turn the heat up to high and bring to a full rolling boil, stirring constantly.
Add the Certo Liquid Pectin to the pot and continue stirring until it comes to a full rolling boil again.
Boil for 1 minute exactly, stirring constantly.
Remove the pot from the heat and fill jars leaving a ¼ inch head space.
Wipe jar rim and threads. Place a flat lid on and screw on a band just until finger tight. Repeat with remaining jars.
Process jam in a hot water bath for 10 minutes.
Remove jars from water bath canner and set on a towel on the counter.
The next day check for a proper seal and store.
Store in a dark cabinet.