How to build a simple food dehydrator one of the oldest vitamin rich methods of food preservation


Through low heat and steady airflow, dehydrating removes enough moisture from food through evaporation to inhibit the growth of bacteria, yeast, and mold. Dehydrating is one of the oldest methods of food preservation and has been used effectively since the dawn of civilisation.

air dried tomatoes retain a rich flavours and vitamin content

My wife and I live in a very remote location growing & making most of our needs to dramatically reduce our footprint. We have a little organic orchard that has proved a wonderful & nutritional addition to our lives for the past 5 years. 

However when it comes to harvest time, we can suffer from an excess of production verses immediate needs. So winter storing of summer fruits, herbs and vegetables is essential to reduce our food intake from an unscrupulous supply chain; a system supplying genetically modified food products that are contaminated with pesticides, preservatives & life chemicals which are only now starting to raise concerns after decades of use. Right now I am writing this piece on the 3rd of April, and we are well into our winter food stores, and yet still have a plentiful supply of dried fruits, vegetables, tomatoes and herbs that we use daily in our cooking as well as daily production in the studio.

underwater 'Vanitas' dated 2010 in shou sugi ban Japanese frame

There are a lot of commercial food dehydrators on the market but they are all rather expensive, clumsy and power hungry. So I have designed and made a modular unit running totally off the sun that (for us in this size presented) turns 10kgs of non gm old breed tomatoes into 400 grammes of profoundly rich tasting and nutritiously dried in just 36 hours. The design is insect proof, and very easy to use. It is painted black as you want not only the solar power to drive the ventilation fan (drawing air upwards and through all the trays) but also to physically heat the trays. This double action has a very fast & natural process time that retains the vitamin & mineral content whilst holding the colour and intensifying the flavour exponentially. The unit seen here has been in operation 3 years and it is faultless, I really cannot recommend this enough. You can modify the design to suit, but the core feature is that the trays align and meet up perfectly to create an insect proof seal, the solar fan does the rest.

food dehydrator design using solar power and retaining all the vitamins and colour of the original food

Again it is an interesting design specifically for use in a dry air climate or air conditioned kitchen for eaxmple; it would need a slight modification to work outside in a humid country for example.

Air dried herbs, fruit or vegetables offer a unique flavour options in the kitchen across the board. The fact that the suns UV rays never reach the food directly means that the foods original colour and rich vitamin / mineral content is fully preserved within the final dried product; for a self build design this is unique. All of the non commercial designs you will see out there are very large and cumbersome, and they use direct sunlight to speed up the drying process which in my view is a huge mistake as the suns UV rays are damaging to the flavour, texture and nutritional value.

The taste of everything passing through this process is simply off the chart using this ‘dark' drying method. Using solar radiation & air flow whilst in complete darkness is an extraordinarily functional & effective system.

I attach here a simple build chart, using cheaply available products only listed as follows…

8 x silicone mesh dehydrator sheet

10 or 12 cms PC cooling fan, drawing 10watts or less - the important thing is constant airflow for the time the product is sealed inside the drying cabinet.

Mosquito netting, you need only a small piece around 20 x 20 cms before fitting

A4 sized Stainless steel fine grade mesh (0.5mm holes maximum)

Small 20w Solar panel & 12v DC supply battery, the unit draws very little power, so you could just plug in a 12v DC power supply and omit this solar power option.

Lengths of 2.5 x 2.5 cms raw untreated pine (or other) wood must be well dried to avoid distortion in use. length determined by the number of trays you wish to build.

Eco wood glue. No VOC's PTAF's or other life chemical products should be used to contaminate your food, I used Shellac.

Good luck with your own build, and please do share your results.

silicone mesh trays prevent the food from sticking

I hope you found this journal entry informative, please stay connected.

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