When I put thicker cut fruit, including bananas, and meats in the dehydrator to dry, they come out chewy. I've never gotten bananas to come out crisp like store bought. There is something added to the chips that make them crisp. Just don't know what it is. The dehydrator simply removes water and some volatile oils. Most of the oils stay in and that's what makes the final product chewy.
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paul, texas KD5IVP