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How to make a solar dehydrator


Okra drying in a solar dehydrator.  Photo by Margaret M Hoff

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Summer’s bounty is at the pinnacle of production: tomatoes, squash, beans, okra, and basil are all in full swing in East Tennessee as well as most parts of the country. Farmers and gardeners have been enjoying fresh produce for several weeks and the excitement of that first summer squash and tomato has begun to wear off. Excitement is replaced with hard work: preserving the bountiful produce so that it can be enjoyed this coming winter. In modern society there are many preservation methods which include freezing, canning, smoking, and the oldest one of all, dehydration. There are several options for dehydrating food: electric dehydrators, ovens, air drying, and sun-drying. The key to drying produce in the sunshine is to make sure that there is constant air flow as well as plenty of sun and heat. Expensive solar dehydrators can be bought but it can be rewarding and economical to build your own solar dehydrator. This article explains how dry extra produce by using the sun’s energy and how to make a solar dehydrator out of items found around the typical home.

To prepare the food for dehydration, wash the produce and blanch the food if it is a fruit or vegetable. To blanch the food, simply submerse the produce in boiling water for 3 minutes and remove it before it begins to cook. Depending on the type of food, it can take up to several days to thoroughly dry the produce. After it is completely dry, put the dried food in the freezer for several days to kill any insect eggs that might contained in the produce. Store the dried produce in a cool, dry place – preferably in an air-tight container.

The simplest way to assemble a solar dehydrator is to find an old picture frame and cover it with material to hold the produce to be dried. Clean the frame with soap and water, rub mineral oil onto the frame to seal it, and then stretch cheese cloth, or 100 percent cotton material, around the frame and secure with a stapler. Another option is to use an old window screen, but make sure that it is not galvanized wire as it can make the food taste odd. In the direct sunlight, brace the frame up in the air so that air can circulate around the food. Because it could take up to several days, move the food inside overnight to avoid moisture from the dew.

In order to speed up the drying process, a heat-catcher can be added to the basic solar dehydrator described above. This idea came from Mother Earth News and can be built out of recycled materials as well. The slideshow photos illustrate this solar dehydrator and illustrate the step-by-step assembly of this dehydrator. The tools needed to assemble the solar dehydrator include a long, shallow cardboard box, duck tape, cheesecloth, clear plastic, scissors, and either another cardboard box or a black plastic seedling tray (without holes in the bottom).

To build the heat catcher section of the dehydrator, take the long, shallow cardboard box and cut a few holes in the sides of the narrow ends. Then either paint the inside black or line it with a black plastic and attach clear plastic across the top of the box, making sure not to cover the holes. Another option for the heat-catcher portion of this dehydrator is to use a black plastic seedling tray instead of the box: cut holes in the ends of it and cover with clear plastic – make sure that the holes are high enough so that the tray is still useful next spring for planting seeds. If using the paint or black plastic, “run” the dehydrator for a couple of days in order to release the fumes that might be present in the paint or plastic.

For the main part of the dehydrator, use the larger cardboard box and cut a hole in the side to connect the heat-catcher. To hold the food, use a (non-galvanized) screen on top of the box or stretch cheesecloth across the top of this box to hold the produce. Set this main box on a table or stool in the direct sunlight, and position the heat-catcher at an angle in the direct line of the sun. Using scrap cardboard, make an air duct between the heat-catcher and the drying box – the solar dehydrator is complete. Remember that this dehydrator is made out of cardboard, so be sure to keep it from getting wet.

Comments

  • margaret Lautenbach 4 years ago

    Now, if I just had more than two green tomatoes on my 20 some plants.....!!!!!

  • Megan, Mother Earth News 4 years ago

    Great, informative article, Margaret! Thank you for mentioning Mother Earth News. We appreciate it, and we're glad you found our piece on building a solar food dehydrator to be so useful. Your okra look great, by the way!

  • Tryg 4 years ago

    Great slideshow! Definitely brought the article to life.

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