A good design for a diy dehydrator

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pengyou

Senior Cook
Joined
Feb 14, 2011
Messages
409
Location
Beijing
I am looking for good plans/ideas for a diy food dehydrator. I have seen more than a dozen online and they all seem to suffer from one major problem. There is no even distribution of the heat so the tray closest to the heat sources is going to dry much faster than the top tray. They all do have some kind of fan but I have built enough things to be able to visualize the results. My main reason for wanting the heat to be more uniform is that I want to have the dehydrator be as little maintenance as possible. The homemade plans I have seen give me the impression that I would have to rotate the trays every couple of hours to make the drying time uniform.

I know that store bought dehydrators stack the trays one on top of another. They are so close to each other and to the heat source that maybe it is not such an issue. Most of the diy models use light bulbs placed together on the bottom of the dryer, usually with a metal plate to deflect the heat. I am thinking of scavenging the heating element and thermostat from a small electric oven/toaster oven to provide the heat. Electric light bulbs may be cheap but they are wasteful because a significant amount of energy is used for light. I have considered making a separate area to heat the air and then using some kind of manifold to distribute the air uniformly to all areas of the box. Maybe even some kind of vortex of moving air?

I am planning on using screens (window type screens with nylon mesh - I am assuming that nylon will be more sanitary than other materials) as the food trays. Each tray will have a pair of screens so that turning the food will simply be a matter of pulling the pair of screens out of the dehydrator box (they will be linked together somehow), flipping it over and inserting it back into the box. I would like to have a dehydrator that will hold 10 trays, about 18"x24". I have already decided that if I go ahead with this, it is not worth my time to play around with a one or two tray machine. I plan on buying a small electric slicer as well, to make the thickness of the fruit/veggies as uniform as possible.

If I can make the heat as uniform as possible, can I get away without having to flip the fruit?

Any comments on any part of this idea are welcome.
 
Last edited:

mcnerd

Head Chef
Joined
Oct 30, 2007
Messages
1,326
Location
Southern California
Have you investigated the fact that consumer dehydrators circulate the air across the trays and not through the trays from bottom to top, so everything gets pretty much the same exposure.
 

DaveSoMD

Master Chef
Moderator Emeritus
Joined
Mar 11, 2008
Messages
7,338
Location
Maryland
Alton Brown made one on Good Eats that was a box fan and a furnace filter. I wouldn't use it for meats, but you might want to try it for veg or fruit.
 

pengyou

Senior Cook
Joined
Feb 14, 2011
Messages
409
Location
Beijing
Thanks! I don't know anyone here in china who has a dehydrator, so cannot take a peek. Thanks for the insight. The commercially available home machines cost almost $200 here - no $50 cheapies :( I will check out Alton Brown's.
 

Arturo11

Assistant Cook
Joined
Apr 27, 2012
Messages
1
I am looking for good plans/ideas for a diy food dehydrator. I have seen more than a dozen online and they all seem to suffer from one major problem. There is no even distribution of the heat so the tray closest to the heat sources is going to dry much faster than the top tray. They all do have some kind of fan but I have built enough things to be able to visualize the results. My main reason for wanting the heat to be more uniform is that I want to have the dehydrator be as little maintenance as possible. The homemade plans I have seen give me the impression that I would have to rotate the trays every couple of hours to make the drying time uniform.

I know that store bought dehydrators stack the trays one on top of another. They are so close to each other and to the heat source that maybe it is not such an issue. Most of the diy models use light bulbs placed together on the bottom of the dryer, usually with a metal plate to deflect the heat. I am thinking of scavenging the heating element and thermostat from a small electric oven/toaster oven to provide the heat. Electric light bulbs may be cheap but they are wasteful because a significant amount of energy is used for light. I have considered making a separate area to heat the air and then using some kind of manifold to distribute the air uniformly to all areas of the box. Maybe even some kind of vortex of moving air?

I am planning on using screens (window type screens with nylon mesh - I am assuming that nylon will be more sanitary than other materials) as the food trays. Each tray will have a pair of screens so that turning the food will simply be a matter of pulling the pair of screens out of the dehydrator box (they will be linked together somehow), flipping it over and inserting it back into the box. I would like to have a dehydrator that will hold 10 trays, about 18"x24". I have already decided that if I go ahead with this, it is not worth my time to play around with a one or two tray machine. I plan on buying a small electric slicer as well, to make the thickness of the fruit/veggies as uniform as possible.

If I can make the heat as uniform as possible, can I get away without having to flip the fruit?

Any comments on any part of this idea are welcome.
Hi pengyou, you have given this much and you points are valid.

I built my own dehydrator, which in essence is a box with trays and some small holes on the top, I then use a cheap heater with a fan to force the hot air through the produce.

Remember that is DRY air that dehydrates, not just heat. so moving the moist air by force fan works well
 
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