Step 1Peel the peaches: Score each peach with a shallow X on the underside. Bring a large pot of water to a gentle boil. Fill a large bowl with ice water. Dip the peaches 4 at a time into the boiling water and scald them for about 30 seconds, then plunge them into the ice water to cool. Slip the skins off, halve the peaches and gently remove the pits. If the skins are tough to remove, use a very sharp paring knife to cut them off. If the peaches do not release easily from the stone, try quartering them to get a better handle on them to remove the stone.
Step 2Combine the sugar, 6 cups of water, ginger, cinnamon sticks and allspice berries in a large pot over medium heat. Simmer until the sugar dissolves, about 15 minutes.
Step 3Pack the peaches as tightly as possible into 8 hot sterilized pint mason jars. Ladle the hot syrup over them and evenly distribute the spices among the jars. Leave 1/4-inch headroom from the top of the jar. Wipe the rims and seal the jars. Process in a boiling water bath for 20 minutes.