Preheat the oven to 140 degrees F.
Combine equal parts water and lemon juice in a bowl large enough to hold all the apples. Peel and core the apples. Cut them into1/4-inch-thick slices and put into the lemon/water mixture. Let soak until all the apples are sliced. Drain the apples. Place the slices on a wire rack fitted over a rimmed baking sheet. Place in the oven and cook for 5 hours.
After 5 hours, remove the apples from the oven and let cool. Once cool, place in jars and seal.
When frozen, dried apple slices will last up to a year. You can naturally dry them if the temperature outside reaches 80 degrees or higher; place on a wooden rack and cover so bugs stay clear.