Dried peaches are a tasty, portable and healthy snack. Keep in mind that the more flavorful the fresh peaches you start out with, the more delicious the dehydrated version will be.
Blanch and Peel the Peaches
Bring a large pot of water to a boil over high heat. Meanwhile, cut a small X in the bottom of each peach using the tip of a paring knife.
Put the peaches into the boiling water for 1 minute. Remove them from the water with a slotted spoon and transfer them to a large bowl. Let them cool just until they are comfortable to handle.
The brief blanching should make it easy to peel the skins off of the peaches by hand, but use a knife if you hit any stubborn spots. Compost or discard the skins. Drop the peeled peaches into a large bowl of acidulated water.
You can make acidulated water by adding 1 1/2 tablespoons of vinegar to a quart of water. The acidulated water step minimizes discoloration in your dried peaches, although keep in mind that they will not have quite as bright a color as commercial dried fruit (which often has sulphur added for the purpose of preventing discoloration).
Slice the Peaches
If you are working with freestone peaches, run a knife around the circumference of each peach. Its halves should be easy to twist apart. Discard the pits. Slice into 1/8 to 1/4-inch thick slices. Return the slices to the acidulated water.
If you are working with clingstone peaches, it's easier to remove the peach flesh from the pit using a paring knife. Cut wedges 1/8 to 1/4-inch thick off of the pits and drop them back into the acidulated water. Discard the pits.
Drain the Peaches
Once all of the peaches are peeled, pitted and sliced, drain them in a colander.
Arrange the Peach Slices for Drying
Place racks inside baking sheets and arrange the peach slices on the racks so that there is space between them on all sides.
Dry the Peaches
Turn the oven on to its lowest setting, which is usually around 150F. Let peaches dry until they are leathery to crisp, which can take anywhere from 6 to 10 hours. If your oven is hotter in some spots than others, turn the baking sheets around occasionally so that the peaches dry evenly.
Cool the Dried Fruit
You won't be completely sure if the peach pieces are fully dehydrated until they have cooled (you know how cookies crisp up after you take them out of the oven? Same deal with dried fruit). Remove the trays from the oven. Let the peaches cool on the trays for 20 minutes.
After the cooling off period, break one of the pieces of fruit in half. There should be no visible moisture along the surface of the break.
Condition the Dried Peaches
Even after the peaches are correctly dehydrated there may still be some residual moisture in the fruit that you can't feel. This shouldn't be enough to prevent the fruit from being safely preserved and mold-free. But you'll have a tastier, better product if you do what is called "conditioning" the dried fruit.
Put the dried, cooled fruit pieces into glass jars, only filling the jars about 2/3 full. Cover the jars. Shake the jars a couple of times a day for one week. This redistributes the fruit pieces as well as any moisture they may still contain. If any condensation shows up on the sides of the jars, your fruit isn't dried well enough yet and it needs to go back into the dehydrator for a few hours.
Once your dried peaches are conditioned, store them in airtight containers away from direct light or heat. It's okay to fully fill the jars at this point: the 2/3 full was just for the conditioning phase when you needed to be able to shake the pieces around.