Add water and lemon juice to a large bowl. Core, peel and slice your fresh apples to about ¼” thick and add them to the bowl. Let everything soak for about 10 minutes.
Place apple slices in a single layer on the dehydrator trays, then turn it on to 135˚ F. Sliced apples will need about 12 hours to dehydrate. Rotate the racks every couple of hours so they dry evenly.
Let the apples cool to room temperature before you remove them from the dehydrator. They will crisp up as they cool, so even if they’re a bit flexible, they’ll become crunchy. If not, you’ll want to dehydrate them for longer.
Transfer the dried apple slices to a glass jar for storage. Be sure to check the jars in a couple of hours to make sure they’re still dry and crisp. If they become soft or there’s any moisture, put them back into the dehydrator.
As long as they’re dry, you can enjoy eating your new crispy snack!