Apples - I try to use fresh apples that I have just bought at the orchard or farmers market. I have used Fuji and Gala apples mostly, although I’ve heard that Zestar and Empire work very well also.
Slice Apples - I use a cast iron apple peeler/corer/slicer. This tool takes care of all three processes at once (it is not totally necessary to either peel or core the apples, but I find doing so produces the chips I am looking for). If you use a peeler/corer/slicer, you will be left with one continuous “coil” of apple. Place coil on a cutting board and make one vertical slice all the way through the apple. This will leave you with individual slices.
You can also use a mandoline or a sharp knife to slice the apples (you are looking for about ⅛ inch thickness).
Prevent Browning - I normally work fast enough moving from slicing to the dehydrator that browning is not a problem, but if your apples are going to sit for a while before going into the dehydrator, you might want to dip them in some lemon juice.
Spices - Some people put a little bit of cinnamon or sugar on their apples before dehydrating, I usually just put them in plain.
Dehydrating - The dehydrator that we use for apple chips does not have temperature control … it is simply on/off. If your dehydrator does have temperature control, set it for about 150 degrees F.
It will probably take about 8 to 12 hours for the apples to dry completely. You’ll know the chips are done when they are not soft or flexible at all.
Store in airtight container after dehydrating.