Build a solar dehydrator

Build a solar dehydrator

Every day we attach more importance to the naturalness and quality of food. Sometimes the latest technologies achieve excellent results in this regard, but artisanal media still have a lot to say. For example, the sun drying of fruits and vegetables. No other method adds more flavor to a tomato, apricot, or fig. It is possible to make a homemade dryer that allows you to take advantage of the excellence of seasonal products throughout the year. It is a much better idea than importing food from the other side of the planet, with the consequent environmental impact.

Solar dewatering is more than just weekend entertainment. It is an ideal application of solar energy. The rays pass through glass sheets that cover trays made of untreated wood where food has been placed on metal grids. The more sophisticated models can have air inlets and outlets, chimneys and heat accumulators, so that air currents are produced that accelerate and favor the drying process.

An efficient method

Natural preservation methods are the key to extending the enjoyment of the abundant foods that the summer harvest produces over time. They are an excellent way to vent excess production in the orchard or to take advantage of the lower prices of the season. Desiccation, which by eliminating water prevents the proliferation of bacteria and molds, is simpler, requires less work and maintains nutrients better than jams and other preserves. In addition, dried foods not only do not lose nutrients or flavor, but they multiply them.

Fortunately, the entire Spanish territory is exposed to the intense summer sun for enough days and hours not to worry. In fact, two days are enough to dry out several kilos of fruit and vegetables.

Basic characteristics

A good dehydrator has the following qualities:
• Dries quickly, much like an electric one.
• It has aeration controls to control the temperature.
• It is easy to load and unload.
• Can be disassembled and stored. It is sturdy, but also lightweight and can be transported.
• Withstands weather conditions and protects food.
• Cleans easily. It has no corners where dirt accumulates.
• The trays are non-stick, made of materials suitable for food.

Parts and assembly

There are many different possibilities to prepare yourself a solar dehydrator. Below, we offer you some registrations, which you can modify depending on your preferences or the material you have:

• Materials must be robust. Cardboard boxes are not worth it. It is advisable to use solid recycled woods, provided they are clean. In addition, we will need screws and carpenter's glue to join the pieces.
• Conveniently raised desiccator for easy inserting and removal of trays. As a base, we can use a disused stool with a seat of approximately 50 x 60 cm. If we do not have one, we can make it with the rungs of a ladder or with any sufficiently robust strip.
• We need a wooden window, if possible with glass, 50 x 60 cm. It can be made with ribbons and a crystal.
• The sides will be obtained from a wooden plank, where we will cut two pieces with two parallel sides of 50 and 30 cm, one of 45.5 cm and another of 50.
• For the back, we need a 45.5 x 60 cm board.
• The top side measures 60 x 30 cm.
• The background measures 50 x 60 cm. On the inner side, we will place a metal plate with the same dimensions. Its function is to accumulate heat. The side of a computer case, available from a recycling plant, is valid for this purpose. We must paint it black.
• We need a rigid metal mesh, 30 x 60 cm. It should not have traces of rust or dirt, as it should remain in contact with food. We will glue it on some supports screwed on the sides.
• About 10 cm below the mesh, we fix other supports to hold a fabric screen, which will act as a moisture absorber. This lampshade can be made with four wooden slats where a piece of cotton fabric can be stapled.
• We join the rear part to the upper side using two hinges. Thus, we can lift it and we can put in and take out the metal mesh tray and the absorbent screen. We can provide this back cover with a string or a hook to hold it open.
• In addition, in the lowest part, we will cut out a 5 x 10 cm rectangle and we will place a piece of mosquito netting and ventilation grilles.
• At the top, we will make another hole. We will place mosquito netting and, with a small hinge, we will fix the piece of wood that we have just cut and that will function as a window to control the temperature.
• An oven-safe thermometer. We can leave it on the absorbent cloth screen, so that it can be seen through the glass.

Ready to start

• Drying occurs when the internal temperature is between 38 and 60 ºC. Underneath, bacteria can grow. On top, the food is cooked. It is necessary to control the temperature by opening and closing the small window installed in the back wood.
• Each food has an optimal temperature for drying.
• Once dried, the food must be stored in airtight containers - if possible, under vacuum - and in a dark and dry place.

How do you use the dehydrator?

You don't have to be a solar wizard to operate the dehydrator. You only need to orient it to the south and introduce the food. If possible, it can be rotated every so often to achieve maximum exposure. Most foods have enough with a day to be perfectly dried. Those richer in water, such as tomatoes or pears, may need a second day.

We must choose fruits and vegetables that are in optimal state of maturity, freshly harvested, if possible. We cut them to the desired thickness - the smaller and finer, the faster they will dehydrate -, place them on the tray and place it in the desiccator. No prior treatment is necessary.

Home-dried foods are free of sulfites, additives used in commercial products that coat dried apricots or raisins with a characteristic shiny, sticky patina. Sulfites can trigger allergic reactions and asthma in sensitive people.

We don't have to wait for the month of August. Since spring, there is enough solar energy that can be used to dry peas, strawberries or apricots. In summer, plums, peaches, zucchini, peppers or tomatoes wait their turn (the taste of sun-dried tomatoes is truly sensational). From the end of the summer and during the fall, we can also dry grapes and mushrooms, for example.
Ecological Logic

Video: DIY Solar Dehydrator (September 2021).