How to Dehydrate Food in an Oven

If you find yourself with too much produce to handle, dehydration is an easy and rewarding way to solve that problem from the comfort of your own kitchen. The process will preserve food for later use while also making nutritious, immensely flavorful snacks, perfect for camping trips or as a part of school lunches. Dehydration can even be a fun way to keep grocery costs down: buying produce in bulk while on sale and dehydrating what isn't used immediately can be a nice way to spice up dishes and try new things in the kitchen without breaking the bank. Best of all, the process can be done at home without an expensive, rarely-used dehydrator! An oven will work just as well, so long as you pay attention and do the right prep work ahead of time.

Man removing food from oven
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How to Dehydrate Food in an Oven

Prep Before Heat

Before turning on your oven, you'll need to prep your food for the dehydration process. Attempting to throw a whole steak or a bunch of carrots into the oven can lead to disaster later, particularly when attempting to dehydrate meats. Thankfully, the hardest part of prepping food for oven dehydration is cutting it to uniform size, and that can be simplified with a mandolin slicer. The prep work necessary will differ depending on what you're dehydrating: fruits (with the exception of things like seedless grapes, figs and slices of watermelon or pineapple) will need to be dipped in a combination of water and lemon juice to preserve their color before being sliced. Some vegetables, particularly root vegetables like carrots and potatoes, need to be blanched for two to six minutes in boiling water (though things like greens, peppers, onions and mushrooms can be dehydrated as-is). Meat should be stripped of fat, to prevent it from turning rancid, then marinated (raw poultry should be cooked). It should then be set in the freezer to firm up before slicing. Once foods have been prepped, they should be cut into quarter-inch slices and laid out on a baking sheet covered with wax paper. If desired, foods can then be dressed with seasonings, sugar or oil to flavor them further.

The Perfect Temperature

To dehydrate food in your oven, you'll need to keep the heat low. The ideal temperature for oven dehydration is roughly 120 degrees Fahrenheit. If your oven can't be set to that temperature specifically, the "warm" function will do just as well. The process can be completed without trouble anywhere under 200 degrees, but the lower the temperature the better. Once your food is prepared and laid out on its tray or trays, simply allow the oven to heat up and set the trays inside, 5 inches apart from one another. If desired, the process can be jump-started by turning the heat up to about 150 degrees, then turning it back down once the surface moisture has evaporated from the food after an hour or two. Drying times will vary depending on the food and your oven. At the fastest, foods like onions and carrots will need between 3 and 6 hours to dehydrate, but fruits and meats can take significantly longer.

Monitoring the Oven

Once your food has been set in the oven to dehydrate, it won't need much attending to. You can safely do other things while the process goes along, but it is still important to keep an eye on your food by checking it every few hours. Just as well, if your oven lacks adequate ventilation, you may need to leave the oven door cracked somewhat to prevent moisture buildup. And if your oven has hot spots and does not heat uniformly, it will be important to turn or adjust your pans every few hours to ensure that the food is drying at the same rate. When your food appears to have shrank, and feels completely dry to the touch, it is ready to cool, at which point it can be stored, or eaten as a tasty, homemade snack!