I am trying to dry sweet potatoe sticks (look like French fries). I’m drying them in a food dehydrator. When they are finished drying they come out looking like they have mold on them even though they are thoroughly dry. I use them for dog treats. Are they moldy or just discoloured? At what temperature should I use? Thanks for any tips.

  • Probably oxidation, but depending on what you are doing mold is not impossible. Pictures might help - please edit those in. What sort of dryer and what temperature are you using now?
    – Ecnerwal
    Commented Nov 15, 2022 at 22:30

1 Answer 1


If the discolouration is white, it's most likely sugar crystallising on the outside, so nothing to worry about. For the dehydrator, you can go fairly hot for sweet potatoes - I would use 80-90 °C for a few hours, and also cook (steam) the potatoes before drying. See this wikipedia page for reference.

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