Place an oven thermometer on the middle of the top tray. Arrange the thermometer so you can see the reading.
Preheat the oven to 140 degrees F. During the process, keep the temperature between 140 and 160 degrees F.
Prepare between 1 to 2 lbs. of food to process. Refer to a drying cookbook, as some foods require blanching or pre-treating. The food should be clean, defects removed and uniformly cut, such as in 1/4-inch slices.
Arrange the foods on drying trays, in a single layer, without the pieces touching each other.
Place the trays in the oven, with one tray per oven rack, situating the trays in the center of the racks to allow for air circulation.
Keep the oven door slightly ajar while drying, between 2 to 4 inches.
Set a portable fan near the oven door and turn on, to provide circulation to the oven.
Rotate the trays every half hour. Refer to your dehydration recipe for how long to dry the food you are preparing.