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Dehydrator Versus Freeze Dryer – What’s the Difference?

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Several people have asked me, “What's the difference between dehydrating and freeze drying?” or “What's the difference between a dehydrator and a freeze dryer?”. Although they perform similar functions – food is dried for storage – how they do it and the resulting product is quite different. We'll take a look at the equipment involved and the final product.

dehydrator versus freeze dryer

What's the Difference Between Dehydrating and Freeze Drying?

First, let's take a look at the processes of dehydrating and freeze drying.

Home Food Drying with a Dehydrator

Home food drying uses dry air and sometimes gentle heat. Dehydration can be as simple as laying some flowers or herbs on a mesh screen to air dry, or as complicated as using a specific recipe, time and temperature setting on a commercial dehydrator.

In a commercial dehydrator, the temperature is typically set between 95°F to 155°F, depending on the food being dried. Delicate items like herbs and flowers are dried at lower temps, while meat is dried at higher temps. Fruits and vegetables are dried between 125°F to 135°F.

Home Food Drying with a Freeze Dryer

Home freeze drying super-chills the food down to around 30 degrees below zero, which takes about 9 hours. Then the home freeze dryer kicks on a high powered vacuum pump, which pulls a complete vacuum in the sealed drying chamber. At this point, the food is warmed and water within the food sublimates directly from ice to vapor. The process is repeated (chill, warm) until a moisture sense indicates that the no more water vapor is being drawn off. At this point the unit beeps to notify the user that freeze drying is complete. The user releases the vacuum and double checks the dryness of the thickest food pieces in the chamber. If food pieces are still cold in the center (indicating dampness), additional time is manually added to the cycle.

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Dehydrating Versus Freeze Drying – How Does the Food Taste?

As food is dehydrated, it typically shrinks up and develops a leathery feel and appearance. Dehydrated food can be eaten “as is” – think raisins, fruit leather or jerky – or rehydrated. Rehydrating is best done with plenty of water and low slow cooking – think soups and stews, or slow cooked oatmeal with dried fruit.

With freeze dried food, the texture is lighter and more airy. There is very little shrinkage, and many foods have a “melt in your mouth” texture when dry. Freeze dried meat strips that we make for fajitas taste like a meat flavored version of cheese puffs. (We call them “meatos”.) The finished product can be easily crushed or crumbled, so care should be taken if you'd like to preserve whole, large pieces of food. An example of freeze dried food are the berries in commercial cereals that feature real berries. Most freeze dried foods rehydrate quickly, so you can have a hot meal in 5-10 minutes. Think “just add water” heat and eat side dishes or entrees.

Dehydrator Versus Freeze Dryer - Both dry food for storage, but we'll discuss how they do it and the difference between freeze dried and dehydrated foods.

Storage of Dehydrated and Freeze Dried Foods

Both dehydrated and freeze dried foods store best in an airtight container with an oxygen absorber for long term storage. That said, dehydrated foods are a little more forgiving if stored less than optimally. Because they take longer to rehydrate, they don't immediately absorb moisture if left out for a short period of time. For instance, I keep jerky and fruit leather that we're eating in plastic zip lock bags or mason jars. They both keep fine for weeks.

Freeze dried foods act more like sponges. Once exposed to air, the clock is ticking. They can go from crisp to soggy in a couple of hours – faster in humid conditions. If you want to store freeze dried food long term, it's essential that it be packed in an airtight container with an oxygen absorber as soon as possible. Initially I started with vacuum sealed mason jars, but I had a number of seals fail in storage. Instead, I've switched to Mylar with an oxygen absorber. So far, so good. The containers I've tested after several months of storage taste freshly packed.

Shelf Life of Dehydrated and Freeze Dried Foods

How long do these foods last in storage? The estimates I've found for dehydrated food storage are all over the place. On the Excalibur website, they give an expected shelf life of 20 years for apples, but only five years for “fruit”. Odd. For veggies they claim 8 to 10 years, and don't offer estimates on meat. Other sites suggest no more than 2-3 months for meats, 1-2 years for other dehydrated foods. In my own experience, after about 3 years, dehydrated fruits and vegetables start to darken and lose flavor. (I keep them cool and out of direct light, vacuum sealed in mason jars.)

The shelf life of properly stored freeze dried foods is nearly universally agreed on as longer. Freeze dried low fat content foods like fruits, vegetables, lean meat, rice, noodles, ect. have a shelf life of 20+ years when packaged properly. Higher fat freeze dried foods and meats have a 10-15 year shelf life. Some commercial freeze dried products are now claiming 30+ year storage life. I'll have to update this post in about 20 years to let you know how my storage turns out.

dehydrator versus freeze dryer

Dehydrator Versus Freeze Dryer – Comparing Equipment

For home food drying, there are a range of equipment options available – including no equipment at all, as mentioned above. You can build your own unit, use a Sun Oven or other solar dryer, or buy an electric dehydrator. Commercial dehydrator costs range from less than a hundred dollars at the low end for small units with temperature control, to hundreds of dollars for the high capacity stainless steel models.

As long as your set up can provide warmth and dry air, it'll probably work. Results may be less than ideal. I have friends in warm humid areas that could not dry larger food pieces without molding in a budget model with no temp control. (I do not recommend electric dehydrators without a temperature control for this reason. If you're going to get a dehydrator, get one that does the job right.)

You can learn more about dehydrator types in the post Home Food Drying – 6 Things You Need to Know to Dehydrate Food at Home.

Freeze Drying

For home freeze drying, at the time of this post, there's only one company making home units. (This is to the best of my knowledge. If you know of another manufacturer, let me know.). That company is Harvest Right out of Salt Lake City, Utah.

As mentioned above, the process of freeze drying is significantly more complicated than dehydrating. The drying chamber must form a perfect vacuum. Materials inside the unit must be able to withstand extreme cold and moderate heat, and to swing between the two. The sensors need to be able to determine when to cycle the machine. There are significantly more moving parts and higher performance demands. As such, the price point is significantly higher. The smallest units start at under $2000, the largest units are just under $3000.

Dehydrating or Freeze Drying – Which is Better?

A freeze dryer is a big investment, but it's the only way to create truly long term shelf stable storage foods at home. If you plan to rotate stock more frequently and don't want to preserve meat and dairy, then a dehydrator can probably get the job done.

I still use a variety of food storage techniques, and I don't plan to change that. Canning, fermenting, drying, freeze drying, freezing, root cellaring – each method brings something different to the table. The flavors and textures are different, how we use the food is different. I like having options.

I think of our freeze dryer as a type of food insurance. While we have been enjoying freeze dried snacks and quick meals, I'm also tucking food away for long term storage. Food prices keep creeping up, and the last time my husband lost his job, it took around a year to find a new position. I feel better knowing that we have some of the basics covered.

What food preservation techniques do you use, and what do you like about them? What techniques would you like to learn more about? Leave a comment below and let me know.

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I’ll continue posting what we’re drying on Instagram, and sharing additional posts to address questions show off the yumminess. If you choose to purchase a Harvest Right freeze dryer through my site, I receive a commission at no extra cost to you. (Thank you.)

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42 Comments

  1. “store best in an airtight container with an oxygen absorber”

    What is an oxygen absorber? And where would you get one?

    Thanks.

    1. Hi Vickie. Oxygen absorbers are small packets of material that absorb oxygen. You sometimes see them in commercial food packages like crackers, to help keep them from getting stale. They’re sold online through Amazon.com and other retailers. I purchased a package that included 100 Mylar bags and oxygen absorbers (click here to see the package). I like that the oxygen absorbers were in packs of ten, so I only needed to open a small amount at one time. You have to be careful and not leave them open to the air, or they’ll absorb oxygen and not work in your packaging.

  2. 1. I wouldn’t buy a bread book because I have a few already plus a dust gathering bread maker.
    2. I had a food dehydrator and didn’t like the look of darkened slices of fruit. Also I was uncertain about the centre texture of the slices which could be not dried enough as it felt juicy.
    3. I have put the occasional punnet of berries in the fridge and re-discovered them ‘freeze dried’. These re-hydrated quite well and totally useable.

    1. 1. Time to donate books and bread machine?
      2. Pretreating does help with the discoloration, but it can only do so much. Slicing fruit thinly helps with dryness.
      3. More like dehydrating than freeze drying, but functional.

  3. Thank you. I have had so-so results with dehydrating so far but then I just have a cheapie unit bought at WalMart. I think the Nesco unit sounds great. I’m older with fewer mouths to feed now so really couldn’t justify the freeze dry unit. Good information.

  4. That’s all well and good, and I would LOVE to have a freeze dryer, but most likely, 99% of all people will not have the $3,000.00 upwards to buy one! I really don’t think that it is cost effective, as to save that much in food, you’d really have to dry a lot, and use a lot. PLUS there is also the fact of where to store this huge investment! Because of these reasons, I don’t think that it is a great idea. Now if you could count on several families to share in desperate times, to go in and buy one with say, 10 other families, that might be do-able, just who gets to keep it? I see too many problems with a home freeze dryer

    1. Many people seem to find money for vacations, expensive clothes, electronics, sports, concerts, ATVs, or other items, so I wouldn’t say that 99% of people wouldn’t have the money to buy one. It’s more a matter of priorities. It’s not for everyone, certainly, but the online forums are filled with people who are putting theirs to good use.

      1. Hello! I’m a little late to the party and would like to add a few thoughts.

        I too am weighing if Freeze Drying is right for me. In addition to all the things mentioned we:

        Are now a family of 2 as our kids are grown. We hope the kids and grandkids will move back closer but no guarantees.

        We camp, hike and RV travel (for 6 months at a time).

        Eating high quality food is very important to us.

        I too am hoping that I can find other families that could share in machine if I purchase one. I read the other day that a gentleman is bartering – he offers to freeze dry others food and he keeps half of the results. This provides for 1/3 of his food. He’s working towards getting closer to 80%-100%. Very interesting idea!

        Thank you so much for posting your thoughts on food preservation!

        1. You’re welcome,Naomi. I think a sharing arrangement could work out well with the right people involved, but like any arrangement, I wouldn’t advise going into it blindly without expectations being clearly spelled out.

      2. Well not everyone makes alot of money either. Maybe Your way to look at things is cheap to your standards but theres alot of people who would use one if it wasn’t so darn expensive.

        1. Never did I imply that it was “cheap”. It’s a big investment, but it’s a complicated piece of equipment – not unlike solar equipment. They’ve brought the price down substantially since they starting selling the units, but they will never be “cheap” because of the tech involved. It is what it is.

    2. Just an opinion, but I think 10 families sharing a freeze dryer would be impossible. I recall reading another article somewhere (sorry, can’t find it now), that there was quite a bit of time needed per batch of food to dry with this method. Besides $3,000.00 is not such a big deal, most young people spend that much on tattoos 😉

      1. It generally takes around 24 hours, depending on the environment and the food being dried, so it would indeed be awkward for that many families to share a unit. I concur that many people spend much more money on things that are much less practical.

        1. Not to mention the maintenance you have mentioned to be sure is done and who and how it would be allocated…and if repairs are needed then is is everyones dime or the person who used it at the time????? also for those who say too expensive, they have a layaway plan….

  5. I put my freeze dryer on layaway….with Harvest Right, they really do right by you. I locked in the price, which at the time was $500 off the unit I wanted, plus an accessory package worth $200. There is no time limit, there are no finance charges and once you pay off roughly 2/3’s, they ship the unit to you and then put you on a payment plan. I for one…cannot wait, as I aspire (and have done so in years past) to grow/raise all our own food and like Laurie, use a variety of storage/preservation methods. For instance, our family loves canned green beans and does not like frozen ones. We have experimented with dehydrated green beans and found they work well in soups/stews.
    This device is not going to end up being as ubiquitous as a microwave as most people….maybe 99% ;0] don’t even cook real food so it would be redundant to freeze dry it. But for those that grow or raise their own food or like to buy in bulk, the freeze dryer would be a useful tool….just like the dishwasher and refrigerator and oven.
    And I cook meals ahead to feed my family because I work the night shift, I will be able to cook in larger batches and not need a third freezer! (Our yearly chicken harvest takes up one) Plus, cooking meals ahead for hedging against inflation or for emergencies is always good.
    As always Laurie, a well thought out article and so timely too!

    1. Thanks, Pam. As I mentioned in the first freeze dryer article, one lady starting making her own single serving meals to take to work, because she often ends up working through lunch hour. When they take their quick “snack breaks” and others hit the vending machines or crack open a granola bar, she uses a cup of hot water to make a whole meal in minutes. Like any tool, it’s value is determined by how much you use it.

  6. Thank you so much for a great article on freeze dryer as well as the comparison article with the dehydrator. I was thinking about getting one but I simply own too many equipment including grain grinder (husband already wants me to start getting rid of occasional user items).
    My dehydrator is almost 30 years old and have been used a lot. I may invest in a new, better dehydrator. I grow organic veggies and vacuum seal either dried ones or vacation seal and freeze. Tomatoes always produce abuntly and I prefer to dry and seal instead of canning. I prefer the dried taste over canned.
    The freeze dryer can dry 10 pounds which is not much considering the amount of veggies one picks from the garden (I get lots of beans, okra, tomatoes basil, parsley bitter mellons, blueberries, etc). Since I spend lots of time in the garden, I most certainly would consider an easier method of storage. I am not sure about freeze drier. Maintenance is time consuming and this one involves cleaning oil. I stopped using food processor since I don’t like washing large items after every use. Don’t get me wrong, I believe that my kitchen electronics seem to last forever is due to the fact that I always clean and take care of my small appliances. I am not sure I want another high maintenance item.
    Thanks for all the advice.

  7. I have dehydrating for 10 years now and you are right it is the color….I opened some sweet potatoes and they where lite yellow…YUCK so I will powder them and use in a stew

    So I am buying a Harvest Right today,,,,but will continue to dehydrate as some things are fine like mushrooms but other things like strawberries and fruit turns dark and is not eye appealing

    1. We’re not big eggplant eaters (but I’m trying a new variety this year in the garden, so maybe it will be a winner). Several people in the freeze dryer groups have tried it with good results. Comment include:

      “I freeze-dried raw ones yesterday, to make into lasagna noodles! They came out beautiful, and very light.”

      “Roast them whole, like for making baba ganoush, and freeze-dry the innards after cooking.”

      “I medium diced mine then sauteed it with a little olive oil in a non- stick pan. Then I Harvest Righted the stuffing out of it!”

      1. So you can use oil…I know that’s a big no-no for dehydration. Would you prepare and bake eggplant parm and then freeze dry or just freeze dry breaded raw slices then prepare eggplant parm ? Eggplant has been one of those things you can never store….it seems like you can only use it when it is fresh or forget it

        1. From the freeze dryer groups, it looks like most people are freeze drying raw sliced eggplant. There are also some who have done sauteed eggplant, but I haven’t seen a full eggplant parm. It might be a little tricky to rehydrate, and/or difficult to dry entirely because of the thickness and density of the ingredients.

  8. I have 5 pumpkins to cut and store . in the fall of 2016 I dehydrated them….this spring Apr of 2017 I am thinking I won’t use this batch for 3 or 4 years,,,,should I freeze dry or dehydrate? I am worried about color again,,,after my yellow sweet potatoes I don’t want to waste my time

    1. I would think that a freeze dried pumpkin puree would easily last 20 years if properly stored. 3-4 years would probably be okay on the dehydrated pumpkin, again, depending on storage conditions.

  9. Your posts on freeze drying have helped me a lot since we purchased our Harvest Right last year. I’m trying to decide the best way to seal and store the finished products. I had just about decided to purchase a Food Saver and use the jar sealer accessory since I have a few hundred quart jars in storage. After read your experiences with lid failure, now I’m not sure. If I buy Mylar bags with O2 absorbers do I still need to vacuum seal them with the absorber inside or can I just fill the bags, add the absorber and heat seal without vacuuming? Its all a little confusing and I trust your information as the voice of experience. It seems a shame not to take economic advantage of all my jars, but I can’t afford costly failures either.

    1. If you use O2 absorbers with the Mylar, you don’t need to vacuum seal. You can vacuum seal, but it’s a pain in the butt. (Mylar is too smooth to use directly in a standard vacuum sealer, so you have to rig up “cheats”.) I compared a few bags with the O2 absorber alone, and with vacuum sealing and the O2 absorber. The O2 absorbed will slightly shrink up the bag as it sucks up the oxygen, without the crushing effect of vacuum sealing.

  10. Thanks so much for your post! I’m actually trying to decide between the two because I want to start making veggie powders myself. I have an idea for a business, but it’s just starting out. I purchased a food dehydrator online to try and dry and then grind the veggies, but I have actually attempted yet. Do you think this will work? I’m willing to invest in the freeze drying unit at some point down the line as a business expens if it’s necessary, but do you think just dehydrating will do the job. Thank you for any input you may have.
    ~Moni

    1. In my experience, most vegetables that are dehydrated in a standard dehydrator tend to be extremely tough and difficult to pulverize. Instead of turning to light, fluffy, powder, they clump and stick together. If you already purchased a dehydrator, give your idea a go and see how you like the results.

      In contrast, all the veggies I’ve run through the freeze dryer are easy to powder – so easy that you want to be careful with packaging so you don’t smash them into dust.

  11. A dehydrator costs a lot LESS than a freeze drier. There are lots of books on food dehydration. I have not seen many books on freeze drying food.

    1. As long as you follow the basic rules, you can freeze dry pretty much anything, so I don’t think most people see a freeze dryer cookbook as necessary. I think I heard about one being worked on, but I don’t know when it’s coming out.

      And yes, dehydrators are less expensive than freeze dryers. A freeze dryer is a much more complicated piece of equipment.

  12. 08/30/21
    Please update your site as the prices of the Harvest Right freeze dryers are much more expensive than you stated in this site. The largest is doubled.
    Thank you,
    Frankie H

    1. “Doubled” is an exaggeration, but like most manufacturers, Harvest Right has seen increased costs, and it’s been four years since the post was written, so prices have increased.

  13. This is great information. Do you by chance have a list of foods and the type of preservation preferred for each? That would be great to get more information on, in order to become more efficient in good storage.

    1. In many cases, it’s a matter of personal preference. Fruits and vegetables work well with both methods, but the taste and texture varies.

      Dairy needs to be freeze dried in most cases. Meat can be dehydrated, but keeps better freeze dried.

      If you’re serious about food storage, it makes sense to get a dehydrating guide, and study online forums for ideas about what can be freeze dried. The bigger Excalibur dehydrators usually ships with a dehydrating guide book. I haven’t heard about a book being out that focuses solely on freeze drying, but I know some people are working on one.

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