Wednesday, September 5, 2012

Dehydrator decision

I used my parent's dehydrator last autumn to preserve part of my hot pepper abundance and at once saw the value and practicality of dehydrating food. The benefits are compounded by the limits of our smallish freezer and inability (for now) of buying a chest freezer.

A few weeks ago I took a great dehydrating class (through the Willy Street Coop by Polly Reott, master food preserver) where I pretty much decided to buy a dehydrator.

Now the decision is which one to buy. Please post your opinions and comments to my three questions below. If you are reading this by email, please go to the blog to post your answers so all can see! Thanks.

Vertical pros and cons

The obvious benefit to the vertical air-flow models is that there are stacking trays, which in some cases can be stacked pretty darn tall. This means that the dehydrator is always the right size for the job. My research (so far) is that vertical (round) dehydrators are cheaper to initially purchase.

However, the trays on the far side of the heating element receive cooler air, and often stacks need to be changed around. The vertical airflow also means that for the most part, you can't mix vegetables in the unit, because peppers below could flavor the tomatoes above.

Also, most vertical units are round. Geometrically speaking, most round and square units will take up about the same counter space but a square unit would provide more tray space.

Horizontal pros and cons

I went online to do some research. Polly highly recommended the "horizontal airflow" models such as the Excalibur they had at Willy West.

You can deduce two of the pro's by reading the cons above; less chance of flavor mixing with the horizontal air flow and more even heating.

However, these units have a fixed number of trays. And, horizontal airflow models tend to be pricier.

My needs

I expect to dehydrate peppers, tomatoes and herbs from my garden. But with one, a whole new world opens up. Crackers? Fruit? Squash?

So,  my three questions are:

  1. Would you recommend buying a round vertical or square horizontal airflow unit?
  2. If side airflow, I have to choose a size, generally 5- or 9-tray. What would you recommend for home use?
  3. With either choice, what brand do you recommend.



  1. I took the same dehydrating class last year and bought a Nesco square with the heat and fan in the top unit. I love it and I don't seem to have a problem with food not drying evenly. I only have 4 trays so I suppose if I added more trays I could start to notice a difference. I have heard the horizontal airflow ones dry more evenly, I just couldn't justify the cost until I had proven to myself I would use it enough. My Nesco still meeats my needs because I tend to work in small batches. Good luck! (Fiona)

  2. I have the 9 tray Excalibur and love it. Besides drying fruits and veggies, I have used it to make fruit or veggie leathers, yogurt, jerky, even to dry shoes... (You can dry big things by taking out several trays). When it is time to dry, we want to get the food processed quickly, and the volume that this can do makes a big difference. Yes, it costs more, but it should last for decades. I highly recommend the horizontal flow tray configuration.

    1. Shawn, I think I need one of these JUST to dry shoes :) Really thought, the idea of being able to remove a tray to dry larger items is a good consideration.

  3. josh,

    thanks for your article. i'm contemplating some sort of food dehydration system, too.

    i have two thoughts, unrelated to your questions (sorry about that):

    1) be selective about the trays. are they made out of plastic? there is some concern that plastic leaches into food and can cause or accelarate existing cancer. are they made out of cheap metal? similar problems there, too. do some research and find out what the safest material is, and then please let us know!

    2) are you into sustainability? anything like a food dehydrator which heats with electricity uses a lot of juice. electricity usage is the #1 cause of climate change (and makes our fish inedible because of mercury). consider a solar food dehydrator. i'm not sure if you'll be able to dry tomatoes that way, but canning them is more environmentally-friendly than drying with an electric dehydrator. the uw-madison ag research station on mineral point road has a solar food dehydrator.

    1. Thank you for your thoughtful responses. I spend a bit of time doing some research on your questions, and appreciate the new info I learned. I thought I'd share it here for all to read.

      I checked into the food tray composition and read that for at least one of the units I'm considering, the plastic trays are FDA approved food-grade materials. Plastic is a concern for me too, a few years ago I got rid of all our plastic storage containers and bought a bunch of Pyrex storage containers. They do have plastic lids, but the food doesn't come in contact with the lids.

      I had not thought of comparing energy usage between canning and dehydrating, so I checked into it.

      I was happy to learn that the average cost of electricity used by the horizontal unit I'm considering is about 4 - 5¢ an hour. We can extrapolate final costs based on what we're drying. A useful comparison for perspective maybe be with an incandescent light bulb - something I can relate to. A 60-watt bulb costs about 1.5¢/hour to operate (depending on cost of energy).

      In the dehydrator class I took, we were advised that with Wisconsin's fickle at best summer weather (except for this year of course) a solar dryer is not dependable for the average person like me who is not constantly tending to it, and can lead to food spoilage if it's not dried quickly enough. I also live in an apartment with a small patio and just a few hours of sunlight. A solar dryer is not an option for me (and many who are blessed with shady yards) so for me, the minimal energy useage and consistent outcome of a dehydrator outweigh the cons.

      I am canning food as well - just did 11 pints of marinara and 4 quarts of tomato juice which I "skimmed" off the top of the tomato puree. I did a quick search to find the energy usage involved with canning.

      I found the following at

      "The energy cost to process the food will vary with the length of processing time and the efficiency of the burner in maintaining the desired processing temperature. In one USDA study, it was estimated that the energy required to process a 7-quart canner of raw-packed green beans, peaches and tomatoes was 1.6, 2.3 and 2.4 kwh, respectively. At 10cents per kwh this amounts to 2.3 to 3.4 cents per quart."

      This isn't apples to apples (pun intended :) but even using the low side of the above calculations, when I add the five hours of simmering tomato puree in my Nesco to boil off liquids, I can't imagine I used less energy than a dehydrator.

      However, I'm mostly interested in dehydrating things I can't can, such as hot peppers, mushrooms (my dad grows them, I eat them :), and fruit when it's fresh and in season (which I may can as well). I want to dehydrate some paste tomatoes (which for foodies, are the equivalent of sun-dried tomatoes). Most of our Wisconsin sun-dried tomatoes come from sunny California. With transportation costs accounting for between seven and 12 percent of overall cost (and carbon emissions) dehydrating at home will probably work out to my advantage, and that of the environment.

      Finally, here's a mom who really know's her math - in this article she amortized equipment over 20 years for a purely economical comparison (does not specifically take energy usage into account)

      Thank you again for helping me think through many aspects of dehydrating, energy usage and carbon emissions. I really appreciate it.

  4. I highly recommend a horizontal version with trays. The huge advantage of this model is that you can remove alternate trays to dehydrate bulkier things. I have one and really like the fact that I can dehydrate whole shiitake mushrooms. I originally came to this opinion from taking a mycology class. I have a very old one completely constructed of metal. I don't know if you can get that any more.

    I've had the vertical kind and think they're underpowered and a poor design, the leather trays inhibit air flow and can allow mold to grow.

    I would love to use a solar dehydrator, but think it's pretty touch and go as to weather and humidity here in Wisconsin. If you needed to dry stuff in July, you'd be fine, but in August and September, very moist veggies like tomatoes might mold overnight. If you could pull your trays inside every night to prevent the dew from wetting your produce, perhaps it would work. Sarah Shatz has one she made, you might ask her about it's practicality.

  5. This in from Zach by email.

    I use a 9 tray Excalibur horizontal and I like it. I've done jerky, fruit, and squash and have turned out well. Typically, you don't end up mixing the food that much. Two big squashes totally fill up my 9 tray. I've had no major problems. Sometimes the food on top/bottom takes a bit longer but I shuffle it around when the middle trays are dry and it finishes up no problem.

  6. This in from Fiona by email.

    I took the same dehydrating class last year and bought a Nesco square with the heat and fan in the top unit. I love it and I don't seem to have a problem with food not drying evenly. I only have 4 trays so I suppose if I added more trays I could start to notice a difference. I have heard the horizontal airflow ones dry more evenly, I just couldn't justify the cost until I had proven to myself I would use it enough. My Nesco still meeats my needs because I tend to work in small batches. Good luck!

  7. This in from Chuck and Diane by email.

    We have an Excalibur. Chuck does all the food dehydrating and he seems to really like that model. In addition to fruit and veggies, he does a few types of crackers (including those flax seed crackers you may remember from one of our dinners/brunches). We even tried dehydrating chicken once for a backpacking trip but it turned into an inedible leather which wouldn't rehydrate.

    We had a stacking dehydrator at one point, and I find the Excalibur to be far more effective and versatile. It is pricier, but better in general. Chuck

  8. No experience myself, but I was impressed with Carol Deppe's report in her book The Resilient Gardener. I found it excerpted in this blog post:
    (Excellent book, btw.)
    - Jon

  9. I have been dehydrating stuff for years, mostly using a round dehydrator such as the one you pictured. I liked it, but I had to rotate the trays in order to even out the drying speed, and it was quite slow. 2 years ago I purchased an STX Dehydrator with 10 trays. It looks pretty much like an Excaliber, but costs quite a bit less, yet seems to work just as well. I have dried sliced potatoes and hashbrowns, mushrooms, blueberries, apples, herbal teas,grapes, and recently experimented with fruit leathers. It has the added feature of being able to make up to 6 pint batches of really good yogurt as well.

  10. Again, thank you all for your comments. We now have a dehydrator, and the house is filled with (nearly noxious) pepper smells :) Which one did we get?

    The obvious choice... the free one that my friend Dale gave us. But even better, he got it at St. Vinny's years ago, so it's onto it's (at a minimum) third owner. Reuse is far better than buying new.

    While old, it has a thermostat, timer and is a horizontal-air-flow with nine trays. How lucky am I?

  11. I wanted to share a resource from my friend Anne, a great dehydrating resource. I'm looking forward to what they recommend about tomatoes. My first batch are, well, perhaps too dry :)