Hello Hannah. I completely understand your frustration with overcomplicated recipes. You truly do not need any artificial additives, specialty powders, or chemical sprays to achieve delicious, crisp sweet potato chips at home. All you need are sweet potatoes, a little standard vegetable oil, and salt.
The primary reason sweet potatoes turn out soggy in the oven comes down to moisture and spacing. Sweet potatoes contain a lot of water and natural sugars. If they are sliced too thick, have excess surface moisture, or are crowded together, they will steam instead of crisping up.
Here is a dependable, traditional method using a standard baking sheet:
1. Slice them thinly and uniformly. Aim for slices that are roughly one-sixteenth of an inch thick. A mandoline slicer makes this quick and consistent, but a sharp chef knife works fine if you slice carefully.
2. Dry the slices thoroughly. Spread the slices out between clean kitchen towels or paper towels and press down firmly to absorb as much surface moisture as possible. Getting them dry before oiling is essential.
3. Use minimal oil. Toss the dried slices in a bowl with just enough vegetable oil to create a very thin, light sheen. If you add too much oil, the chips will soak it up and stay soft rather than crisping.
4. Arrange in a single layer with space. Lay the slices out on your baking sheet ensuring that none of them overlap or touch. If necessary, bake in batches across multiple pans so steam can escape freely.
5. Bake low and slow. Preheat your oven to 300 degrees Fahrenheit (150 degrees Celsius). High heat burns the natural sugars before the chip has dried out properly. Bake for about 20 to 25 minutes, flip each slice, and bake for an additional 10 to 15 minutes until the edges curl and look lightly golden.
6. Season and cool. Transfer the pan to a cooling rack and immediately sprinkle with fine salt while they are still hot so the salt adheres. The chips will continue to crisp as they cool for 5 minutes.
Taking care with slice thickness and giving the chips enough room on the sheet will solve the texture issues every time.