When I decided to begin my dehydrating career, I went through all easily available information about commercially available dehydrators. Unfortunately, there seemed to be only two types of dehydrators: ones that worked fine and had at least three digits (some of them had four) in their price tags, and then there were those ridiculously small, fragile pieces of crap, which you can find on late night cable channel “shopping network” and such tv shows: “buy one right now, and we send you a head lice comb and a can of motor oil, absolutely free!!”.
So, I was left with the only choice to build one by myself.
Where to start? What do I need?
First, what is a working dehydrator? It is a confined space with some kind of racks to hold the food stuff and a system that leads the warm air in and the moisture out. Should not be too difficult.
I was about to discard my daughters cheap old beat up table, when I realized that the four drawer cabinet in the other end of the table would be a perfect dehydrator frame (Frame, 0 €/$). So I separated the cabinet from the table, removed bottoms of the drawers, and stapled cheap plastic mesh on to the drawers frames (Mesh, 4 €/$ for m2 from local hardware store).
The only problem left was the air circulation. To solve that, I removed the front footing part of the cabinet (warm air would go in from there). But how to get the moisture out? Should I drill holes on the top of the cabinet? No, too much work. I decided to take care of the outgoing air by sliding open the top drawer, just enough to let air out from the sides, not from the top. My air circulating solution later proved to be perfect. And additionally, a cabinet without any holes on top of it can be used as a patio coffee table, even during the dehydrating sessions.
Then to the source of the warm air. In the summer time, I am using my dehydrator on the patio, therefore, the air source should be at least somewhat weather resistant. The patio is covered, so there will be no direct rain, but anyway. Fortunately, I happen to have a portable DEFA car interior heater with high/low settings (Warm air blower, 0 €/$). Outgoing air temperature of these devices is just right for dehydrating purpose. After all, they were designed to warm up the car interior, not to burn the carpets or melt the plastics inside the car.
If the car interior heater would not have been available, it would have been quite easy to find them on sale for less than 20€/$. As a replacement device for a car interior heater, any warm (not hot) air blower will do (about 10€/$ at the local hardware store). I have even seen people using boot drying devices in their food dehydrators. As long as one can keep dehydrators temperature between 35 and 50 degrees (That is 95 and 123 degrees Fahrenheit, respectively), it should be OK.
Now it was time the test run my dehydrator.
So, I sliced some carrots and placed them onto the mesh on all four drawers, closed the three bottom drawers leaving an exterior temperature sensor wire of internal/external thermometer (the thermometer I use for measuring the temperature in and outside of my home, 0 €/$, about 10€/$ at the local hardware store) between the second and the third drawer, and left the top drawer open just enough to let the air escape from the sides.
Heater settings on high, after about 15 minutes the temperature was 35, and it kept climbing till it reached 47, a perfect temperature, and never went above 50. I was lucky to get it right straight away, but I also found that, when necessary, it is very easy to adjust the temperature by moving the air blower a bit further away from the opening at the bottom of the cabinet.
After using and storing my dehydrator outdoors for about 3 months, I realized that the side panels were beginning to bend outward and there was a good chance that the drawers could fall from their tracks. The bending was quite obviously caused by the constant shift between the moist conditions outdoors and the dry spells by my frequent food preparation experiments. Therefore, I had to figure out a way to support the side panels. For that, I drilled a hole to both of the side panels in a mid frontal position where the supporting structure would not interfere with the movement of the drawers. Then I pushed a 6 mm threaded rod (rod 1m, 1€/$, local hardware store) trough the holes, tightened the rod with washer and wing nut on both sides of the cabinet so that the sides were straight again and the drawers were gliding smoothly.
If I would build similar kind of dehydrator again, I would install the supporting rod when building the dehydrator. The dehydrator will work just fine for a while even without the rod, but bending of the side panels at some point is inevitable, so why not do it right in the first time.
1 obsolete drawer cabinet (3-5 drawers)
1 m2 mesh (equivalent to polypropylene mosquito net, non-toxic, somewhat heat resistant. Metal wire mesh is not recommended because in tends to rust and give not so nice extra aroma to the dried food items.)
1 warm air blower (Defa portable car interior heater or something similar)
Optional but recommended:
0.5 m threaded rod (6mm)
2 washers (6mm)
2 wing nuts (6mm)
Flat head screwdriver
Office stapler (or carpenters stapler)
Optional but recommended:
Drill (electric or manual)
Drill bit (6-8 mm)
Make sure that the drawer cabinet is not painted with some soluble poison cocktail, and that the mesh is suitable for food preparation.
Wash and dry the cabinet and the mesh.
Use screwdriver to pry (or fist to beat) off the front footing of the cabinet.
Use screwdriver to pry off the bottoms of your drawers.
Measure the frame of the drawer and use scissors to cut a bit over sized pieces of the mesh for each drawer.
Staple a piece of mesh on the top side of each drawer.
Place the drawers back into the cabinet.
On the mid frontal section of the cabinets side panels, find an area in which the supporting rod does not interfere with the movement of the drawers. Drill a hole on each of the side panels. Use hacksaw to cut a suitable piece from the threaded rod (2-4 cm longer than the exterior width of the cabinet).
Push the threaded rod through the holes and tighten it using the washers and the wing nuts so that you still can comfortably slide the drawers.
Securing the structural integrity of the dehydrator may require gluing of any of the loose parts of the frames of the drawers or the cabinet. If so, remember to use some non-toxic carpenters glue.
If required, it is possible to double the capacity of the dehydrator by attaching additional pieces of mesh to the bottom parts of the drawer frames. Filling and emptying the dehydrator becomes somewhat more difficult though.
Place a thin layer of the goodies of your choice on the mesh. Place the drawers back into the cabinet leaving the top drawer slightly open so that the moist air can escape through the upper frontal corners of the dehydrator.
Place the warm air blower to blow air into the dehydrator through the bottom frontal opening (the one that was created by removing the front footing of the cabinet).
Place the sensor of the thermometer into the dehydrator (the wire fits well between the drawers).
The temperature should be between 35 and 50 C, usually not above 50 C. Adjust the temperature by using the heaters settings or by changing its location.
Instructions for dehydrating a variety of different food items can be found on these pages in the near future.