Bring a saucepan of water to a boil. Cut a shallow X in the bottom of each peach; blanch for 30 seconds. Transfer with a slotted spoon to an ice bath to stop the cooking process. Once cool enough to handle, you should be able to peel the peaches very easily. Cut in half and remove pits, then chop the rest of the peaches into roughly 1/2-inch pieces. You should have about 5 cups of chopped fruit.Toss chopped peaches with 3 tablespoons of lemon juice and 1 cup of sugar. Cover tightly and refrigerate for a few hours or overnight, stirring once or twice to keep the peaches coated with their own juice (this will keep them from oxidizing).Fill a large stock pot or canning pot 2/3 full with water; place a rack of some sort in the bottom and place over medium-high heat. Wash/sterilize your jars and submerge in water bath as it heats. The pot should be just about boiling by the time the jam is ready to go. Keep jars in hot (not boiling) water until ready to use.In a bowl, whisk together remaining 1 cup sugar and pectin until evenly incorporated.Pour prepared fruit and all of the juices into a large, heavy saucepan. Bring to a simmer and cook for 10 to 15 minutes, mashing the fruit as it softens using a potato masher or by pressing the chunks of fruit against the side of the pan with a spoon or spatula. Softer, more ripe peaches won’t need quite as long here. Ideally you’re looking for roughly mashed fruit rather than cleanly cut chunks, which will make for an ideal jam texture.Add remaining 3 tablespoons lemon juice and calcium water, along with 6 tablespoons (about 2/of the bourbon. Bring to a full rolling boil, stirring occasionally.Whisk in sugar/pectin mixture, stirring continuously until mixture returns to a full rolling boil. Stir in remaining 2 tablespoons bourbon, then remove from heat. Ladle jam into hot jars, leaving 1/4-inch of head space. Wipe jar rims and screw on lids. Process in boiling water for 10 minutes, then transfer to a wire rack to cool completely. Check seals. Any unsealed jars should be refrigerated and used within 3 weeks.