"The tragic reality is that very few sustainable systems are designed or applied by those who hold power, and the reason for this is obvious and simple: to let people arrange their own food, energy and shelter is to lose economic and political control over them. We should cease to look to power structures, hierarchical systems, or governments to help us, and devise ways to help ourselves." - Bill Mollison

Tuesday, August 11, 2009

Our Solar Food Dehydrator

We have been making a crude, but good, nutritious and delicious form of fruit leather using our barn's roof and the sun as a giant solar dehydrator. With berry season in full swing and the amount of space allotted for berries in our freezers already past capacity we begin to focus on other preservation methods. One of these is drying or dehydrating the fruit. We do have a small electric dehydrator that could be forced to run non-stop from now well into mid-December. That's not really an option though as it would waste a lot of electricity and be much too hard on the dehydrator that is mostly used to dry morel mushrooms in the very early spring.

Fortunately, as long as the summer provides us with enough sunshine and not too much humidity we can easily dry various fruits and berries right on top of our barn roof. Any sunny spot works great for this, a car roof, the top of one's cold frame, or even an old stump. The important part is to get the product into the sun and off the ground away from, in our case, ants, cats, and small children. The barn roof works great for this as the one side is angled towards the south and gets full sun most of the day.

One of my drying screens full of shallots for next year's sets. We don't dry these in the sun.

The combination of corrugated galvanized metal roofing, slope of the roof, and the sun creates a perfect scenario for drying food. The corrugation provides air spaces under a screen or tray allowing the air to move up the roof carrying away the moisture from under the trays of food. The galvanized metal also gets hot and reflects heat back onto the food. We use old metal pizza pans for the fruit leather and I have screens for drying apples, pears, plums, tomatoes and so on. Right now we are working on drying raspberries.

Once the berries are picked we simply crush them into a puree and spread evenly onto the pans, about a quarter inch thick. Evenly is the key word as any thin spots will dry first, stick and tear holes in the leather when you try to remove it. Now if you want to be fancy, the puree can be strained of seeds. We like it in it's more natural state and leave the seeds in, besides it's a lot less work that way.

After 5-8 hours in the sun, or when the top portion appears dry but before the bottom begins to harden, the fruit needs to be flipped over to finish drying. I use a metal spatula for this and carefully work my way under the fruit folding it over as I go until it can be carefully turned. Another 3 or more hours and it should be ready. Sometimes this process takes two days to complete, one for each side. It all depends upon what you are drying. For example, it always takes me two days to dry raspberries...7 hours on one side and 4 on the other. Once thoroughly dried there should be no moist spots and the leather will hold together quite well, it can then be either frozen or stored in an airtight container, we use old gallon jars for this.

Voilà! Ready to be torn or cut up into smaller pieces for storage. What a great hiking snack this makes.

Properly dried fruit can keep this way for years, if not dried enough it may start to mold.


Amy said...

I didn't realize foods could be dried so quickly outdoors, I guess I always figured it would take longer than that. Good to know.

Silke Powers said...

You two are so ingenious, Mike, truly creative in your garden and with your harvest! Well, here in GA in the summer, you could hydrate your food outside... I watered yesterday morning and last night, there were still wet patches on our driveway even though the sun shone all day and it was 96 degrees - that's humidity for you... I bet that dried raspberry tastes deliciously intense! :) Silke

P.S. Thanks for your much appreciated comment on my blog!!

Knit Witch said...

Huh. I never thought of that before. Great tutorial! Our dehydrator drives me crazy with the amount of electricity and heat it puts out - not to mention noise! This is a much better alternative.

WeekendFarmer said...

NICE!!! You made me homesick. That is how Bengali mangoes are preserved. I have a friend who dries all the mangoes she gets from the locals and makes amazing dried mangoes. Funny thing is ...none of the neighbors like mangoes and she ends up with literally TONS of mangoes and her whole house smells divine in summer. I will do some shrimp this year that way to make fish suace. Good reminder : ).

el said...


Too much humidity and far too many fruit flies 'round here to try that, but...that sure looks yummy. Good use of that free sunshine.

angie said...

What about flies?

Flo said...

Wow, this sounds like a really cool idea. I think there are too many wasps etc. around for us to try it this year but this sounds like a much better method than the fruit leather made with sugar - will definitely try this next year!

Mr. H. said...


It all depends upon what you are drying, if there is a breeze, how hot it is, and humidity. That said, we manage to work around all those issues and have been successfully drying foods outside for a number of years now.:)

Mr. H. said...


This can be done in a humid environment as well. The trick is to build an enclosed dryer that gets enough heat(sun) and airflow. I have never had to do this but have read various plans for this type of dryer many times. But yes, it is more difficult to dry outside in a humid environment.

Silke, the first batch we did was a little overdone but still tasted good, the second bigger batch was perfect, and yes, so intensely flavored.

Mr. H. said...

Knit Witch,

When we first started drying food years ago it was with a small Nesco food dehydrator that we quickly destroyed from over use. Yes, it did suck up the electricity...now, Nesco #2 is used sparingly. Besides, our whole evolution revolves around learning to do things as they were done in the past...just in case.

Mr. H. said...


Dried mangoes, and as many as she wants...heaven on earth. I have always wanted to dry fish (salmon) and hope to someday get the chance. Dried shrimp for fish sauce, now that sounds really interesting.

Mr. H. said...


It really does turn into a tasty snack. We have had issues with fruit flies in the past but not so much of late...luckily. I think they are fruit fies.

I sure wish I had a car load of peaches to dry...lucky you.:)

Mr. H. said...


flies? What flies?:) Seriously though, if flies or bees are an issue a mesh screen can be placed over the drying food. The only difference will be it takes a little bit longer to dry.

Mr. H. said...


It is much better for you than fruit leather made with sugar. I hope you do try it, if so let me know how it turns out for you. You can always dry like this with a mesh screen over the top to keep bugs out...it just takes a bit longer.

LynnS said...

Simply brilliant, taking this process 5 steps backwards to how it used to be made. Yes, this "technology" is used in other more primitive countries. And it used to be done here in America, too....We forgot that, though. Most of us don't know the Colonial ways because we got all fancy. LOL Isn't it ironic that the very energy that gave us freedom has made us slaves to purchase it?

I love it....Nothing wrong with bringing back 'the old fashioned ways' to America. In many ways, this is actually the easier way than w/ a dehydrator. Mine has 15 shelves and fruit leather is rather messy with the base-material required -- which, I might add has Teflon there. If I knew then what I know now about Teflon....aack!

Mr. H. said...


You know I am always contemplating these things and have come to the conclusion that humans, for the most part, are just smart enough to create all these issues but not nearly smart enough to avoid them. It seems that the human race has been on a crash course for disaster since the beginning of time.

Yes, the majority has sold their soul for the so called easy life that is everything but easy. So an understanding of reality allows a few of us take the best parts of both worlds and strive for a life of independence. Perhaps someday our knowledge will be of use to the desperate masses...perhaps not.

I must say that it certainly is a lot less lonely now that I have a few like minded people to communicate with.

Frustrated Farmer Rick said...

Man that fruit leather looks like a great idea to steal. Last year I just froze the excess raspberries we had but I like the idea of fruit leathers as a way to save some of the summer.

Mr. H. said...


We really like it, especially the grandson. The important part is to make sure you have a few sunny days to do it in. We should have been doing it off and on all summer but waited until we ran out of freezer space. Now we have to work around the August rains. It is supposed to be back in the 90's next week though...perfect for drying raspberries.

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