How to start dehydrating food

Each US household loses about $2,000 a year in wasted food.

By Bridget Reed Morawski | Published Apr 1, 2023 11:59 AM EDT

In the United States, almost 32 percent of the average household's purchased food goes to waste, a total annual loss of around $240 billion. All that squandered sustenance is hard on a household budget, as the moment spoiled food hits the trash can or compost heap, your money goes with it. But if you want to, you know, get what you paid for and eat your groceries instead, consider dehydrating them before they go bad.

Dehydrating food is not some new trend; Indigenous people in pre-colonial North America created a dried food called pemmican, and cultures around the world have used similar techniques for generations. It's easy to see why: removing moisture from something edible prolongs its shelf life and makes it easier to transport.

Today, there are environmental benefits as well. Food decaying in landfills generates a significant amount of methane, a potent greenhouse gas, and climate change is one of the biggest risks to American agriculture. Of course, composting can help, but you (and everyone else) may benefit more from dehydrating or otherwise preserving food to eat later.

Safely dehydrating food is fairly straightforward, according to Bryan Mayer, a butchery educator based in Kailua, Hawaii. He points out that safe dehydration techniques predate the Industrial Revolution by centuries.

"This has been a part of how we’ve made food safe to eat pre-refrigeration and certainly pre-canning, so it's something that's totally within reach for most people," he explains. "It's certainly something fun to do and something that I think we can use on an individual basis to reduce waste, keep things out of compost."

Mayer says the main thing to know about drying raw meat, poultry, and fish is that you’ll need to first cook it to a food-safe temperature specific to that protein before reducing the heat to a level more appropriate for dehydrating. If you need a reference, the US Department of Agriculture has a list of safe minimum internal temperatures for various foods.

Beyond that, start with the best-quality cut you can get, Mayer says. He recommends leaner cuts because you’ll have less overall work to do, since you’ll want to remove the fat if there is any.

"You’ll want to slice it however thick or thin you want, and then you’ll want to marinate it, usually up to 24 hours," he says. The longer you marinate, the more any salt within your spice mix will seep into the meat, which means more time for the salt to penetrate cells and break things down.

[Related: Your food could be better if you salt it at the right time]

Any other spices will just sit on the surface of the meat, not making molecular changes like salt will, Mayer adds. There are no rules for what spices or other flavorings you can add to your meat jerky; you can go for tried-and-true options like barbecue sauce or mustard, or add something less likely to be in store-bought varieties, like Dr. Pepper or red wine and fish sauce. The People's Choice Beef Jerky, a jerky purveyor, has a long list of possible meat jerky flavor combos.

Once you’ve decided the meat has marinated for long enough, line up the strips on a dehydrator rack or on a pan rack in your oven. Experiment with different lengths of time and temperatures, adding more time for lower temperatures (but always make sure as much moisture has been sucked from the meat as possible before you stop).

If you’re dehydrating fruits, vegetables, herbs, or mushrooms, it's important to wash or brush them to remove any dirt, dust, or other contaminants, and prevent new ones, like insects, from getting into your newly dehydrated goods. That will help prevent the food from spoiling.

You’ll then want to cut everything into same-size pieces to ensure dehydration occurs evenly across your rack; a mandoline will help keep your cuts consistent.

Colorado State University recommends choosing one of several fruit pretreatment methods, using pure ascorbic acid crystals, citric acid, or other similar substances to help break down tough skins, prevent discoloration and kill off unhealthy bacteria.

Because home-dried produce may not dehydrate evenly, you should mitigate mold growth by "conditioning"—loosely packing it in a shakeable container every day for a week—to help distribute any remaining moisture, according to the National Center for Home Food Preservation at the University of Georgia.

For vegetables, cut off any inedible parts, like stems or rot, before washing and thoroughly drying. Different vegetables dehydrate more easily after blanching, or briefly boiling then dunking in an ice bath, according to the Food Network.

Herbs get a similar treatment: trim off any bruised, discolored, or inedible bits, as well as thicker stems, before you arrange them on the dehydrating rack. But you’ll have less room for temperature and time experimentation with the herbs, so set your dehydrator or countertop oven to the lowest possible setting and let them bake until they’re crumbly. You can also microwave smaller amounts sandwiched between paper towels for two or three minutes, then 30-second intervals until they’re dry.

[Related: Grow long and healthy hair with this DIY rosemary water]

If you don't want to mechanically dry your herbs, sage, thyme, rosemary and other sturdy herbs can be bundled and air-dried indoors, according to the Oregon State University Master Food Preserver Program. Tender herbs, like basil and mint, can also be bundled and air dried, but OSU recommends hanging them inside a paper bag with vent holes cut in the top and side, closing the top, and placing it somewhere warm with good air circulation.

Dehydrating mushrooms is similar to other types of food dehydration, except you won't need to think about pretreatment. You’ll want to clean them thoroughly, ensure no bugs are present, and trim off any inedible or tough bits before cutting them into even-size pieces. Different mushrooms will have different dehydrating times based on how moist they are, so a dryer mushroom won't need as much time in the heat. Like fruits and vegetables, you’ll want to condition your mushrooms by storing them loosely in a sealed container and shaking them daily for a week.

At the height of mushroom season, Rob Rubba, a plant-based chef and co-owner of Oyster Oyster in Washington, D.C., says his restaurant "easily" receives deliveries of 100 pounds of local mushrooms each week. Not all of that will look pretty enough to be plated, so the less-attractive items end up dehydrated for use in future recipes.

That's to say, there's no maximum amount to how much food you can dehydrate—as long as you have enough space, heat, and time. But best practice is to lay everything out in an even layer with nothing overlapping on a rack on a sheet pan to maximize heat and air flow. Reasonably speaking, you can dehydrate as much as you can fit in your oven or on your dehydrator racks. You can also dehydrate different types of foods at once, but Rubba recommends considering flavor pairings in case of contamination. Apples and garlic, for example, wouldn't taste great together.

If you have an oven (countertop or otherwise) that can reach a low enough temperature (around 200 degrees Fahrenheit), you shouldn't need to buy a food dehydrator. It's also possible to sun-dry some produce, like tomatoes, apricots, peppers, grapes, or any fruits with high sugar and acid content. This requires an elevated rack or screen that allows air to pass on all sides, and avoiding materials that could stain or contaminate the food. Produce only, though: the Department of Agriculture doesn't recommend sun-drying meat because it's harder to keep everything healthy and hygienic.

That being said, while a dehydrator will cost money and take up space, having one means you can multitask in the kitchen by dehydrating while you use the oven for other tasks. A food dehydrator is also purpose-built, so you’ll be able to fine-tune your temperature settings, keep the heat and dryness consistent, and use levels of racks to dehydrate more than you could inside a single-rack countertop oven. In a pinch, you may also be able to build your own dehydrator.

But if you’re really low on space for a new kitchen appliance and feel like using a full oven would be a waste, Rubba suggests using the waning heat from cooking or baking in the oven to dehydrate food.

"As the oven cools, there’ll be a declining temperature that will be slowly drying it out," he explains, adding that this is also a great way to make breadcrumbs. "The next day, you could pull [the food] out and have something dehydrated—and that's a good way of just utilizing leftover energy."

Some items, like dried meat sticks, are probably best as quick snacks and meal supplements. But you can do a lot with dried fruits, vegetables, herbs, and mushrooms to make meals prettier or tastier.

Dehydrated mushrooms can become vegan jerky, but they can also be remoistened and used in stocks, stews, or anywhere you would use a regular mushroom. Harvard University's T.H. Chan School of Public Health recommends rehydrating mushrooms for 15 to 20 minutes in boiling water.

[Related: 4 benefits of eating mushrooms]

Other dried produce can be rehydrated too. Generally, you’ll need to soak 1 cup of dried food in 1 to 3 cups of water for 30 to 90 minutes, and the University of Georgia has a handy chart you can refer to when rehydrating fruits and vegetables (page 7 of the linked PDF).

Slices or pieces of dried pineapple, oranges, kiwis, or other fruits can be used to garnish drinks and meals, or be eaten as a snack. Veggies can be dried into chips that can be eaten as-is or crushed into other things, like pasta dough and salads, or as a topping. Herbs can be dehydrated and ground into homemade spice mixes.

For bread service at Oyster Oyster, Rubba's team makes a vegan marigold butter with "an abundance of marigold flowers that we dehydrate to garnish that and give it these pops of lemony, fragrant flavor on the butter," he explains.

Another benefit of dehydrating foods is the flavor concentration that occurs when the water is stripped out, which Rubba, a 2023 James Beard award finalist, says can lead to "amazing" complexity.

"We’ve boiled and smoked whole pumpkins and then dehydrated those for a week to get this solid, giant piece that we can grate onto dishes, kind of reminiscent of a bonito [flake]," he explains. Rubba's restaurant has also "reduced cucumber juice slowly in the dehydrator, and it takes on these wild, spicy flavors that you wouldn't expect from a cucumber."

Proper storage is key to making dehydrated foods last. Rubba recommends using an airtight container to loosely pack anything you dehydrate and popping a silica packet inside to wick away any remaining moisture. Just make sure the packet isn't broken and that you clean or thoroughly check the food when you use it again—silica beads are generally nontoxic but can be a choking hazard.

That's going to give anything dehydrated a longer life, especially if you live in a humid climate, he explains, adding that dried fruits, veg, and ‘shrooms are shelf-stable but shouldn't be exposed to moisture, so they’re better stored in the pantry than in the fridge.

Dried herbs, fruits, and vegetables should last up to a year but will not keep as long under hotter conditions; the National Center for Home Food Preservation says most dried fruits can be stored for one year at 60 degrees Fahrenheit, six months at 80 degrees, and that vegetables will last about half as long as fruits.

Properly dried meat won't last nearly as long, according to the center—only about two weeks in a sealed container at room temperature, although you can refrigerate or freeze it to increase its shelf life. But odds are you’ll eat it long before two weeks pass.