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How to Build a Solar Dehydrator to Preserve Food

If you are a gardener, you understand the abundance that comes during harvest season can be overwhelming. Instead of frantically searching for friends who will take away your fresh tomatoes or spending hours over a hot stove on a humid summer day making hundreds of canned tomato sauce, a solar dehydrator might be an option for you. One of the easiest ways to preserve food is through dehydrating. Instead of relying on expensive electric dehydrators that use huge amounts of electricity, a solar dehydrator can preserve large amounts of food with nothing but an innovative design to capture the sun´s energy.

How Does the Sun Dry and Preserve Food?

The sun obviously creates heat. When you concentrate that heat into a small, concentrated space where you place certain fruits, vegetables, herbs, mushrooms and other food stuffs, the moisture is pulled out of the food by the heat.

Food spoils because of yeasts, bacteria, mold, and certain fungi begin to colonize food once they have sat around for long enough. Like all life, however, these creatures need water to survive and propagate. If you have properly dehydrated your foods, the lack of water is a type of defense mechanism against the agents that cause to spoil and go bad.

For a solar dehydrator to property function, a source of direct, powerful, and constant heat is needed. Fortunately, in most places, the late summer months and early days of autumn when basketfuls of fresh food are being harvested almost daily also offer days of clear skies, plentiful sun, and a lack of rain. This allows for solar dehydrators to work at their maximum potential exactly when you will most need it. If you can move warm air over thinly sliced foods, you should be successful in using your solar dehydrator.

What Foods Can and Cannot Be Preserved in a Solar Dehydrator?

While solar dehydrators work great for almost all types of fruits and vegetables, trying to dry meat in a solar dehydrator could lead to a mess and a potentially dangerously contaminated food source. Fresh meat attracts much more wild bacteria, yeasts and molds than do fruits and vegetables. Since solar dehydrators aren´t air tight (they need entrances and exits for the sun-heated air to move through the drying chamber), chances are that your meat might very well attract a host of flies and other unwanted visitors.

Furthermore, your solar dehydrator will obviously produce much less heat at night (when there is no sun). This lack of a heat source for 8 to 10 hours a day doesn’t allow for a constant drying temperature which meats need to be preserved through dehydration.

Solar Dehydrator

Almost all fruits and vegetables can be dehydrated with a solar dehydrator. However, you will find that “wetter” fruits and vegetables such as tomatoes, pineapple, peaches, and the like will take a little more effort to properly dehydrate. While you can easily make dried zucchini chips with your solar dehydrator even on a cloudy day (because of the relatively low water content of zucchini), the sun-dried tomatoes that you have been craving need to be saved for a time when the local meteorologist predicts several days of hot, dry sun.

Apart from fruits and vegetables, you can also use your solar dehydrator to dry mushrooms and herbs. A small, diversified herb spiral in front of your home will give you more than enough fresh herbs that you can dry out for teas, medicines, and spices that will last you throughout the winter. If you grow your own mushrooms or enjoy foraging through the forest for a flush of morels, you can also use your solar dehydrator to make dried mushrooms. Since fresh mushrooms only last for a few days before going bad, drying out mushrooms is often the best way to keep a steady supply with you until the next harvest or jaunt through the woods.

A Step by Step Guide to Build Your Own Solar Dehydrator

All solar dehydrators need some sort of glass-encased solar collector, a drying chamber, mesh trays where you can put your thinly sliced fruits, vegetables, and mushrooms, and an air entrance and exit so that air can move through the collector.
Below, we offer a guide on how to build an easy to build solar dehydrator that incorporates these elements. We don’t include any sort of dimensions so that you can decide on how large or small you want to make your own solar dehydrator.

• A piece of rectangularly shaped plywood
• Two 2×4 that are as long as your plywood piece
• A piece of glass to fit over the box that you are making. Make sure that it is a little bit shorter than your plywood piece.
• Black paints
• Nails or screws
• A drill and large drill bit
• A wooden box that is the same size as your plywood
• Screen to fit on top of the box

• Screw or nail your 2x4s around the edges of the plywood to make a sort of frame or shallow box.
• Drill several holes in one of the short ends of your box. These holes will be the air intake for your solar dehydrator.
• Paint everything black since the color black captures the most heat.
• Attach the glass to the top of your box. This will capture the heat from the sun. Made
• Place the other box (where you will be storing your thinly sliced foods on top of the warming unit. The vent holes should be on the higher end. As the sun enters through the glass into the black painted warming chamber, the air will heat up and then escape upwards (heat rises, remember) into the dehydrating chamber.
• Make several mesh trays and place them in the dehydrating chamber where you will place your thinly sliced food stuffs.
• Place your dehydrator in a place where it receives full sun. You will most likely want to move it during the day so that the sun’s rays are directly hitting the warming chamber.

How to Cook with Dried Food?

Once your foods are dried out, you need to store them in air tight bags such as zip lock bags. When you add water to your dehydrated food, the cells in those foodstuffs sucks up the water. A few sun-dried tomatoes added to a stew or spaghetti pasta will go a long way. You can also enjoy dried food without rehydrating it. Dried fruits make a wonderful addition to any cereal or trail mix.

The Simplicity and Practicality of a Solar Dehydrator

For about $20 dollars you can build a solar dehydrator that will offer you a practical way to preserve large amounts of fruits, vegetables, mushrooms, and herbs without depending on fossil fuel energy. If you live in an area that has a decent amount of sun and heat, a well-designed solar dehydrator is an essential companion during harvest season.

Tobias Roberts

After working in the development industry for over a decade, Tobias decided it was time to stop advising Central American farmers how to do things if he didn´t have a piece of land to live coherently with what he taught. Together with his family he runs a small agro-forestry farm, tourism cooperative, and natural building collective in the mountains of El Salvador.


  1. Better designs have the warm air rising up through the heat collector panel then falling down through the food being dried. This way as the warm air absorbs water and becomes more dense it pulls more hot air through after it. The rate of air flow is more critical than its temperature to removing water quickly.

  2. This is something I’d like to learn more about. Diagrams would be helpful. Any suggestions? Thanks, Alex.

  3. I recently had to replace my solar Hot water system as the water froze in the panels and warped them. I am going to try and use one for my solar dryer. I will let you know how it works out.

  4. It’s kinda light on details. If I didn’t already know how it’s done I wouldn’t feel 100% ready to build based on this alone. I’m building a collapsible dehydrator for a boat, so looking around to find non-toxic mesh. I think there’s a duty of care regarding suggesting non-toxic materials.

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