A Beginner’s Guide to Dehydrating Food

Why dehydrate?

There’s almost no easier way to preserve food than dehydrating. Used for thousands of years to help food last without refrigeration, drying is one of the fastest and least expensive ways to save your harvest. It can also lighten the weight of foods made for camping and backpacking—saving your back and your wallet.

Dehydrating dramatically reduces the moisture content of your food, allowing it to last longer and still taste delicious.

But what is food dehydration? It’s a process that reduces a food’s moisture content to between 5 and 20%. Within that range, the bacterium that causes food to decay can’t survive. By removing moisture from your favorite foods, you’re also extending their lifespan.

Types of food dehydrating

There are a few ways to go about dehydrating your food, but some methods are more successful than others. That’s because modern tools have helped improve the rate of dehydration, reducing the chance your food will spoil. Here are the most common methods used today.

Sun drying

It’s hard to think of an older or simpler way to preserve food than sun drying. For about 12,000 years people have sliced fruit and placed it on racks or lines in the sunshine. Sun drying is very effective in places with long periods of hot sun. The ancient Romans commonly ate raisins and dried figs thanks to their Mediterranean climate. But anywhere with a minimum temperature of 86 F and a relative humidity of 60% will work. Just remember that fruit takes several days to dry thoroughly. Place on a mesh screen—avoiding anything galvanized—and cover with a second screen to deter flies and other insects.

Air drying

Like sun drying, air drying is an ancient method of dehydrating food. The main difference is that air drying usually takes place in the shade. That’s because this method helps preserves anything that needs protection from the sun’s rays. It works well for delicate greens and herbs—especially those you’re saving for culinary mixes or herbal teas.

Solar drying

A step up from sun drying, solar drying uses a dehydrator powered by the sun to passively dry your food. Since there’s no element to provide heat or fans to circulate the air, solar drying uses no electricity. Solar dryers work outdoors and are usually designed like a mini tabletop greenhouse.

Related: Solar Food Dehydration: How to Sun Dry Your Food

Oven drying

Oven drying uses your home oven to slowly dry food at temperatures around 140 F. Because ovens are so large, they’re not the most efficient dryers on the block. But they can save you the trouble of buying an extra appliance if quick drying is your goal. They can also warm up your house, since you’ll need to prop the door open to let the moisture escape. If you’re thinking of drying food in your oven, check to make sure your oven goes low enough. Anything over 140 F will cook your food instead of drying it.

Electric dehydrating

Add modern technology to age-old drying techniques and presto: you have electric dehydrators. These little powerhouses come equipped with fans and elements to quickly and efficiently dry your food. That means virtually no spoilage and a tasty end result. Most electric dehydrators also come with a temperature gauge and adjustment dial. This helps to speed or slow drying time depending on what you’re processing. If your food dehydrator does have a fan, consider using it in your garage or another area where noise won’t matter. This advice also applies if you’re using your food dehydrator in summer and you don’t want to heat up your living space.

An Excalibur food dehydrator is great for drying fruits, vegetables, fruit leathers, jerky, fish, herbs, and soaked grains or nuts.

Dehydrating in a microwave oven

If you are a devotee of microwave cooking and only have a small amount of food to dehydrate, you might consider using your microwave set on ‘defrost’ to dry fruits and herbs. In general, microwaved fruits will take 20 to 40 minutes to dry fully, but keep checking on them so you don’t overdo it. Herbs placed in the microwave take 2 to 3 minutes.

What can you dehydrate?

You can dehydrate almost any fresh food, but some things dehydrate better than others. Here are some of the best things to put in a dehydrator.

• Fruits (apples, bananas, apricots, peaches, pears, cherries, blueberries) for eating as snacks or chopped in granola and trail mixes, or dried as purees for fruit leather.
• Vegetables (carrots, mushrooms, onions, peas, beans, tomatoes) for adding to soups, stews, and backpacking meals.
• Meat and fish (ground beef, chicken, or turkey; sliced meats; cured meats; fresh fish; beef jerky) for adding to backpacking meals or storing for soup and stew ingredients.
• Nuts, seeds (walnuts, hazelnuts, almonds, pecans, macadamia) after soaking or sprouting, to make them more digestible.
• Sprouted grains (rice, buckwheat, barley, quinoa, amaranth) to preserve nutrients and to store for flours, granolas, and baking.
• Herbs (oregano, basil, parsley, dill, fennel, mint, lemon balm, hyssop) for later use in teas, baking, and cooking.
• Crackers, breads, and granolas for raw food diets.

Related: Extend Your Fall harvest by Dehydrating Fruits and Vegetables

Preparing food for dehydrating

Tools

The main goal in preparing food for dehydrating is to get an even thickness. That way things will dehydrate at the same rate, leaving you with a uniform end result. One or two thicker pieces that don’t dry fully can result in spoilage during storage.

To make sure you get the best result possible, use the right tool for the job.

One tool that has been around for a long time is this apple slicing device. The model below is cast iron and is over 20 years old (and still going). For processing fruit like apples and pears, it works like a charm to slice, peel, and core simultaneously.

Look for one without plastic parts. The rubber suction cup on the bottom helps seal the tool to your counter. Some models come with a clamp, but these can be a little finicky if your counter top isn’t a standard size.

A sharp, short paring knife and a hand peeler are useful for peeling and cutting fruit and vegetables.

A food processor or grater can also be useful for slicing, dicing, and chopping ingredients for soups, stews, and snacks.

How thick to slice

When slicing fruits and vegetables for dehydrating, trim to ¼ to ½ inch thick for best results. Slice meat thinner where possible.

What about peeling?

It’s not necessary to peel everything you dehydrate. The main reason to remove the skins from fruits and vegetables is to get rid of imperfections that might affect taste and appearance. You might also choose to remove the skins from non-organic produce to lessen exposure to pesticides.

Related: Pesticides in Produce

If you do want to remove skins from fruits like peaches, apricots, or tomatoes, dip them in boiling water for up to 60 seconds. Next place in cold water for another 60 seconds, or until the skins start to crinkle and lift. The skins will now come off easily by hand.

You can blanch vegetables that normally take longer to cook by steaming for 2 to 5 minutes. This will help preserve nutrients and prevent flavor loss before drying.

To blanch or not to blanch

Blanching refers to pre-heating your vegetables, fruits, and meats before placing them in your dehydrator. People usually blanch vegetables—particularly those that take longer to cook—because it helps prevent flavor loss before drying. The easiest way to blanch is to place vegetables in the basket of your steamer and heat water beneath. Steam for 2 to 5 minutes until vegetables are heated to the center.

The most common vegetables to blanch include:

• Asparagus (3 to 5 minutes)
• Broccoli (3 to 5 minutes)
• Cabbage (2 to 3 minutes)
• Carrots (3 to 4 minutes)
• Corn (1 to 3 minutes)
• Green beans (4 to 5 minutes)
• Peas (3 minutes)
• Kale, spinach (just until wilted)

Blanching some vegetables before dehydrating can help preserve flavor and quality.

Dipping for color and flavor

There’s a reason commercially prepared dried fruit retains its color and texture. Often it has been dipped in preservatives. When added to the fruit’s surface, these preservatives help save the look and taste of the fresh fruit.

That doesn’t mean you have to dip your own food into a preservative before drying, but it is worth considering how to extend your food’s shelf life. Here are some options that are especially good at stopping light-colored fruits from darkening.

Ascorbic acid: Dissolve 1 tablespoon of pure ascorbic acid into 1 quart of water. Add sliced or chopped food to the solution and let sit for no longer than one hour. Remove, drain, and rinse lightly before adding to dehydrator trays. You can usually find ascorbic acid at your local health food or grocery store.

Citric acid: Dissolve 1 tablespoon of citric acid in crystalline form. Treat as above. Citric acid is only 1/8 as effective as ascorbic acid and will give your fruits a tarter taste. Buy citric acid at your local health food or grocery store.

Fruit juice: Stir 1 cup lemon juice into 1 quart of water. Dip fruit for up to 10 minutes, and then drain well. Like citric acid above, fruit juice is not as effective as ascorbic acid (about 1/6 as much) and will leave a tart taste on fruit.

Sodium bisulfite: Dissolve 1 teaspoon of sodium bisulfite powder in 1 quart of water. Soak cut fruit for 2 minutes before removing, draining, and rinsing. Don’t reuse sodium bisulfite solution because it will be less effective the next time around. Also be cautious about sulfite allergies, which are common.

How to dry your food

Dehydrating fruits

For the best dried fruit, choose high quality produce that was picked when ripe. Ripe fruit is at its peak sugar content, which means sweeter snacks. But watch for anything overripe or bruised: these may turn black while drying.

Wash skins if you’re planning to leave them on, then core or pit (if required) and slice to an even thickness. Place on dehydrating trays and dry at 135 to 145 F until pliable.

But how long to dehydrate fruit? For fruits like apples, bananas, peaches, and nectarines, drying times will range from 6 to 16 hours. Apricots, grapes, figs, and pears can take anywhere between 20 to 36 hours. Check every 2 to 3 hours within those ranges, rotating trays if necessary.

Don’t add new fruit to your dehydrator if an old batch is still in the works: this will cause partially dried fruit to absorb moisture.

Dehydrating vegetables

Vegetables dry more quickly than fruits, but they also spoil more quickly. Take care when preparing and do everything you can to preserve their freshness before drying.
That includes storing in the fridge or on produce-saving paper, only preparing as much as you can handle in one load, and washing in cold water.

Remove any tough pieces of skin or stem, cutting away bruises and spots. Slice to an even thickness using a food processor or spiralizer. Choose smaller lengths over larger ones to speed drying. Blanch where necessary (as noted above).

Place on dehydrator trays without overlapping and dry at 125 F. Tomatoes and onions are the exception and are best dried at 145 F. Drying times will range from 4 to 10 hours depending on the vegetable and size of your pieces.

If possible, don’t dry strong smelling vegetables at the same time as the milder smelling varieties. Brussels sprouts, onions, peppers, and garlic will leave their signature scent in other foods.

How to dehydrate meat and fish

Choose only fresh, lean meat and low-fat varieties of fish for drying, since fat will spoil quickly. Don’t dehydrate pork, unless you’re using sliced, cured ham.

When dehydrating cooked meat, remove fat and cut into cubes about ½ inch. Spread on trays and dry at 145 F. Most cooked meats will take between 6 and 12 hours to dry fully. Pat dry if any oil surfaces during the dehydration process. You can also dehydrate (cooked) ground beef in the same way.

To make jerkies for snacks and camping trips, you’ll need to cut meat into thin, uniform strips. Next, marinate in brine or dry cure using a salty “rub” for 6 to 12 hours in the refrigerator. Once cured, brush off the strips and dehydrate at 160 F. Reduce to 145 F until strips crack (but don’t break) when bent.

Dehydrating nuts and seeds

Why would anyone dehydrate nuts and seeds when they’re already tasty raw? Some people with digestive issues find that soaking and dehydrating nuts and seeds make them easier to handle. That’s because raw nuts contain enzyme inhibitors. Soaking helps break down these inhibitors, making nuts and seeds more digestible.

To prepare nuts for dehydrating, soak overnight in a solution of salt and water (about 1 tablespoon sea salt to 4 cups of nuts covered in water). Drain and spread in a single layer on dehydrator trays. Dry at 145 F for 12 to 24 hours. This recipe works well for cashews, almonds, pecans, walnuts, and pumpkin seeds.

Dehydrating herbs

Herbs are one of the easiest and quickest foods to dry. There’s little preparation and they store for a long time without losing their flavor.

Harvest your favorite herbs in the morning, preferably earlier in the year before flowers bloom. If it is seeds you’re after, such as coriander and celery, gather on a dry day when the sun is out. Snip into single-stem lengths, gather in a bundle, and hang in the shade. Or arrange on dehydrator trays in a single layer and dry at 95 to 105 F for 2 to 4 hours. Herbs that have finished drying will be brittle and crumble easily when touched.

Related: 10 Culinary Herbs to Grow and Dry

To process, hold single herb branches over a sheet pan or piece of beeswax cloth and remove by rubbing your fingers along the stem’s length. Gather and store in dry jars.

Frequently asked questions about food dehydration

Food preservation comparisons

Dehydrated vs. canned food

Canning food exposes whatever you’re preserving to high temperatures. This leads to 60 to 80% nutrient loss depending on the food. In contrast, the average nutrients lost through dehydration is about 3 to 5 %.

Canned food is exposed to high temperatures, leading to 60-80% nutrient loss. Dehydrated food loses an average of 5-8% nutrients.

Canning is usually more labor intensive than dehydrating. That’s because it involves preparing your food and sterilizing jars, along with making brines and syrups for processing. Canned food is already moist and can often be eaten raw. Some dehydrated foods need to be soaked or reconstituted before eating, which can lengthen meal preparation times.

Dehydrated vs. freeze dried food

Dehydrating removes 85 to 95% of the moisture in your food. Freeze drying removes up to 99%. That means freeze dried food will last longer and be lighter than dehydrated food, but it’s also costlier to produce.

Freeze drying works by lowering the temperature inside a vacuum-sealed chamber and then raising the temperature until the water in the food changes from a liquid to a gas. A freeze-dryer typically costs anywhere from $2,000 to $6,000.

Getting ready to dry

Drying fruits and veggies is a great way to make your harvest last and reduce food packaging. Preparing your own dehydrated food for outdoor adventures and long- or short-term emergency storage can help you feel prepared and secure.

Are you ready to start dehydrating? Visit our product page for more information on electric food dehydrators of all sizes.