Basics of Food Dehydration

This information is taken from the University of Illinois at Urbana-Champaign, College of Agriculture, Cooperative Extension Service, Circular 1227. For even more detailed information please visit their website.

Drying is the oldest method of preserving food. The early American settlers dried foods such as corn, apple slices, currants, grapes, and meat. Compared with other methods, drying is quite simple. In fact, you may already have most of the equipment on hand. Dried foods keep well because the moisture content is so low that spoilage organisms cannot grow.

Drying will never replace canning and freezing because these methods do a better job of retaining the taste, appearance, and nutritive value of fresh food. But drying is an excellent way to preserve foods that can add variety to meals and provide delicious, nutritious snacks. One of the biggest advantages of dried foods is that they take much less storage space than canned or frozen foods.

Recommended methods for canning and freezing have been determined by research and widespread experience. Home drying, however, does not have firmly established procedures. Food can be dried several ways, for example, by the sun if the air is hot and dry enough, or in an oven or dryer if the climate is humid.

With the renewed interest in gardening and natural foods and because of the high cost of commercially dried products, drying foods at home is becoming popular again. Drying is not difficult, but it does take time and a lot of attention. Although there are different drying methods, the guidelines remain the same.

Although solar drying is a popular and very inexpensive method, some areas do not have a suitable climate for it. Dependable solar dehydration of foods requires 3 to 5 consecutive days when the temperature is 95 degrees F. and the humidity is very low.

Drying food in the oven of a kitchen range, on the other hand, can be very expensive. In an electric oven, drying food has been found to be nine to twelve times as costly as canning it. Food dehydrators are less expensive to operate but are only useful for a few months of the year. A convection oven can be the most economical investment if the proper model is chosen. A convection oven that has a controllable temperature starting at 120 degrees F. and a continuous operation feature rather than a timer-controlled one will function quite well as a dehydrator during the gardening months. For the rest of the year it can be used as a tabletop oven.

Dehydrating foods is still one of those things that is a little intimidating to us, but we are researching it and getting ready to attempt some things soon. We will post our progress as we learn!


  • Bdadfdjkl

    I like that the research says that dehydrating foods will never replace canning because it doesn’t retain the appearance and nutritive value as well as canning… pretty sure dehydrated foods retain MORE nutrients than canning. 

    I’ve found that dehydrating has worked a lot better for me and my family. This article seemed pretty negative and would have discouraged me from dehydrating if I hadn’t already been doing it. I’m actually disappointed in a Post from you guys… that may be a first! 

    • The article was actually written by someone else as referenced in the beginning. This was written before we had any experience at all and have since tried more. Dehydrating is great.

  • Ddthdfoster

    Hello – We purchased a dehydrator about a month ago, and we love it! We have dehydrated onions, zucchini, cabbage, peppers, watermelon, cantaloupe, bananas, tomatoes, strawberries,,,,hmmm have I left anything out? I have to tell you we are wonderfully pleased with the taste of everything. My husband is a very good eater anyway, and loves the dried tomatoes just out of the bag! Everything has a more concentrated taste. The watermelon was amazing….just like taffy….

  • Queenofkeyboards

    I bought a dehydrator last summer and did apples, tomoatoes. strawberries, blueberries, and jerky. However, I have a question about my tomatoes. They turned out really dark and they taste different than regular tomatoes. I used them in chili and ended up adding some brown sugar to make the chili taste like my regular chili. What did I do wrong to make them taste so “dark” for lack of another word? I just broke them up into chunks and threw them in the chili.

    Am I wrong in thinking that the rehydrated stuff will taste as good as the original before I dried it? Thanks for any help.

    • I dehydrated a lot of tomatoes last year and developed a routine where I collected the juice and odd bits and pureed that for a leather. Some of the leather and some of the “perfect” tomato slices got dark–they were burned! I didn’t think it was possible to burn anything in a dehydrator but it is, take my word for it–even at a low temperature. I like the flavour of slightly burned tomatoes so I didn’t sweat it–I just used them up first. I had heard that it’s impossible to dehydrate anything TOO much, and better too much than not enough, but I’ve learned that with some things you do have to be more careful. Now I know that tomatoes are one of those things.

      I don’t think all rehydrated stuff tastes just as good as the fresh stuff. Some tastes even better (pineapple for example). But I haven’t enjoyed dehydrated apples as much, and I’ve had problems getting green beans to properly rehydrate–they seem to be one of those things you CAN dehydrate too much, but it’s also possible it didn’t work well because I didn’t blanch them first. This year that’s what I’m testing. I love, love, love the convenience of dehydrated sweet potatoes/yams. Just pour some boiling water on some broken up yam leather and voila, ready-to-serve! And they do taste just the same.

      I think you just have to experiment until you find what works for you, and what works and what doesn’t. 

      • Ddthdfoster

        Hi Connie — we love our dehydrator, my next step is doing leathers. Though I have dehydrated many things, don’t have enough experience yet with the rehydrating. Most things we are just eating, and love it! Yes, experimentation is key!

  • Thanks for the link ladies. Defintiely going to be adding that to our new links page!

  • Thanks for the link ladies. Defintiely going to be adding that to our new links page!

  • I got all my information from Tammy above, as well. She's the one who finally made me bite the bullet and by an excalibur dehydrater. So far, we've had great results. I'm still working on learning how to actually use the dehydrated foods, though.

  • I got all my information from Tammy above, as well. She's the one who finally made me bite the bullet and by an excalibur dehydrater. So far, we've had great results. I'm still working on learning how to actually use the dehydrated foods, though.

  • I got all my information from Tammy above, as well. She's the one who finally made me bite the bullet and by an excalibur dehydrater. So far, we've had great results. I'm still working on learning how to actually use the dehydrated foods, though.

  • I got all my information from Tammy above, as well. She's the one who finally made me bite the bullet and by an excalibur dehydrater. So far, we've had great results. I'm still working on learning how to actually use the dehydrated foods, though.

  • Check out http://www.dehydrate2store.com. Tammy has LOTS of wonderful information and probably has answer to most of your questions right on the website.

  • Check out http://www.dehydrate2store.com. Tammy has LOTS of wonderful information and probably has answer to most of your questions right on the website.

  • Check out http://www.dehydrate2store.com. Tammy has LOTS of wonderful information and probably has answer to most of your questions right on the website.

  • Oh, guys! Dehydrating is SO easy. And you can make a lot of your own dehydrated meals. Fruit leather, mac and cheese, thicker stews, thicker chili. It's like freezing. If you see it in the freezer section, you can usually freeze it, though sometimes you have to make some prep before doing it. Same with dehydrating.

    I was able to score 2 flats of 12 “clamshells” of blueberries for $.33 a CLAMSHELL! I didn't have room in my freezer, so I dehydrated them.
    I simply sorted out the too-soft ones and tossed those (in 24 'shells, I had about 2 'shells worth of bad ones.) I was able to get 10 'shells at a time onto my little dehydrator. I had no idea how to dehydrate them, so I went on the internet. Info overload. So I just said, what the heck. The first batch I didn't both to break the skins first, I just plopped them on the tray and turned it on. Because blueberries have a lot of water in them, it took about 24 hrs to get them crisp dry – which is how I wanted them for storage. (If you want them less crisp, take them out sooner.) The second batch I too, a sharp, pointed knife and poked a hole in EACH one. That WAS time consuming, but they seemed to dry faster – only taking about 18 hrs to get crisp. After about 8 hrs, I checked on them. Some of them were already dried enough, so I took them out. I also chose to rotate the trays so they would dry a little more evenly. 24 'shells dried down to about two 2quart bags. Easily stored, easily snacked on or baked with. (you can either rehydrate them in a little warm water or plop them into what ever your making with a little extra water added to account for them “drinking” some of the water.

    I probably spent about 2-3 hrs having to sort, rinse, prick, rotate, etc, but most of it was prepping them. The other bit of time was in checking and rotating the trays. $8 for 2 quart bags of dried blueberries and 2-3hrs work are worth it to me. I would have paid $$$$ in the grocery store for dehydrated ones. And I KNOW what's in them. NOTHING but berries!

  • Oh, guys! Dehydrating is SO easy. And you can make a lot of your own dehydrated meals. Fruit leather, mac and cheese, thicker stews, thicker chili. It’s like freezing. If you see it in the freezer section, you can usually freeze it, though sometimes you have to make some prep before doing it. Same with dehydrating.

    I was able to score 2 flats of 12 “clamshells” of blueberries for $.33 a CLAMSHELL! I didn’t have room in my freezer, so I dehydrated them.
    I simply sorted out the too-soft ones and tossed those (in 24 ‘shells, I had about 2 ‘shells worth of bad ones.) I was able to get 10 ‘shells at a time onto my little dehydrator. I had no idea how to dehydrate them, so I went on the internet. Info overload. So I just said, what the heck. The first batch I didn’t both to break the skins first, I just plopped them on the tray and turned it on. Because blueberries have a lot of water in them, it took about 24 hrs to get them crisp dry – which is how I wanted them for storage. (If you want them less crisp, take them out sooner.) The second batch I too, a sharp, pointed knife and poked a hole in EACH one. That WAS time consuming, but they seemed to dry faster – only taking about 18 hrs to get crisp. After about 8 hrs, I checked on them. Some of them were already dried enough, so I took them out. I also chose to rotate the trays so they would dry a little more evenly. 24 ‘shells dried down to about two 2quart bags. Easily stored, easily snacked on or baked with. (you can either rehydrate them in a little warm water or plop them into what ever your making with a little extra water added to account for them “drinking” some of the water.

    I probably spent about 2-3 hrs having to sort, rinse, prick, rotate, etc, but most of it was prepping them. The other bit of time was in checking and rotating the trays. $8 for 2 quart bags of dried blueberries and 2-3hrs work are worth it to me. I would have paid $$$$ in the grocery store for dehydrated ones. And I KNOW what’s in them. NOTHING but berries!

  • Oh, guys! Dehydrating is SO easy. And you can make a lot of your own dehydrated meals. Fruit leather, mac and cheese, thicker stews, thicker chili. It's like freezing. If you see it in the freezer section, you can usually freeze it, though sometimes you have to make some prep before doing it. Same with dehydrating.

    I was able to score 2 flats of 12 “clamshells” of blueberries for $.33 a CLAMSHELL! I didn't have room in my freezer, so I dehydrated them.
    I simply sorted out the too-soft ones and tossed those (in 24 'shells, I had about 2 'shells worth of bad ones.) I was able to get 10 'shells at a time onto my little dehydrator. I had no idea how to dehydrate them, so I went on the internet. Info overload. So I just said, what the heck. The first batch I didn't both to break the skins first, I just plopped them on the tray and turned it on. Because blueberries have a lot of water in them, it took about 24 hrs to get them crisp dry – which is how I wanted them for storage. (If you want them less crisp, take them out sooner.) The second batch I too, a sharp, pointed knife and poked a hole in EACH one. That WAS time consuming, but they seemed to dry faster – only taking about 18 hrs to get crisp. After about 8 hrs, I checked on them. Some of them were already dried enough, so I took them out. I also chose to rotate the trays so they would dry a little more evenly. 24 'shells dried down to about two 2quart bags. Easily stored, easily snacked on or baked with. (you can either rehydrate them in a little warm water or plop them into what ever your making with a little extra water added to account for them “drinking” some of the water.

    I probably spent about 2-3 hrs having to sort, rinse, prick, rotate, etc, but most of it was prepping them. The other bit of time was in checking and rotating the trays. $8 for 2 quart bags of dried blueberries and 2-3hrs work are worth it to me. I would have paid $$$$ in the grocery store for dehydrated ones. And I KNOW what's in them. NOTHING but berries!

  • My family loves banana chips and apple chips. I did tomatoes this spring and they are wonderful to just throw in any dish and they rehydrate in about 10 minutes.

  • My family loves banana chips and apple chips. I did tomatoes this spring and they are wonderful to just throw in any dish and they rehydrate in about 10 minutes.

  • thanks

  • thanks

  • It depends on how you are using them. For soups I just throw them in. When I use dehydrated onions I use them dry. If you are using fruits for a smoothie or something you would want to rehydrate it first.

  • It depends on how you are using them. For soups I just throw them in. When I use dehydrated onions I use them dry. If you are using fruits for a smoothie or something you would want to rehydrate it first.

  • i was curious about dehydrate foods…do you have to rehydrate them before you use them or do they rehydrate as they are cooking?

  • i was curious about dehydrate foods…do you have to rehydrate them before you use them or do they rehydrate as they are cooking?