The rings turned out really well, were extremely easy to make, and weren't very time consuming. The down side to this method is that, compared to all but the smallest dehydrators, you can only dry a small number of apple rings at a time. Still, if you don't see yourself dehydrating a lot of foods, this is a useful method.
What You Need:
Lemon juice (optional)
Warming drawer attached to an oven
How to Do It:
1. Preheat the warming drawer. The temperature of the drawer should be no more than 140 degrees F. On my stove, this was one mark below the "medium" setting.
2. Wash the apples, then run through the corer and cut into rings. I left the peels on (since the peels add a lot of good nutrition), but you can remove the peel if you like. You can core and slice into rings by hand, too, but remember: Keep the slices as close to the same thickness as possible, or you'll end up with some slices drying much faster than others.
3. If desired, toss the apple rings in lemon juice. This prevents them from browning. (I skipped this step.)
4. Place the slices in a single layer on a cooling rack. Place the cooling rack in the warming drawer. My slices took only 3 hours to dry, but depending upon how juicy the apples are and how thick you sliced them, it could take up to 6 hours for them to completely dry. Be sure to turn the slices from time to time.
5. Test for doneness by pressing down on some slices with your fingernail. When no juice comes out, the slices are finished drying. Remove the from the warming drawer, keep on the cooling rack, and place in a dry, warm location for 12 hours.
6. Store dried apple rings in airtight containers or bags.
Slices can be eaten as is, or they can be soaked for about 12 hours to moisten.