Saturday, November 21, 2009

Building the solar dehydrator


A couple years back manthing built us a convection solar dehydrator. We had found some plans for this online and although we didn't want to use the cardboard boxes, decided it was feasible making it out of wood so that it is more permanent.We didn't however have the spare windows at the time to make the chute attachment or the top cover from glass. Instead we used a small section of greenhouse plastic to cover both of those areas. we have used this over two years and the plastic is still doing fine.

The bottom chamber has black plastic on bottom as you can see. there are holes drilled at the bottom and the top of the chamber to allow airflow,as the chamber heats up hot air is forced into the dehydration chamber where it circulates through and goes out the vent in the top cover to the trays.

We currently have 3 sets of trays to stack on one another to dry fruits and veggies. I dont know how much higher we could feasibly go and still have the convection needed to dry properly.The food trays are lined with screen and the lowest is about 6 inches above the bottom of the dehydrating chamber.

this project took about 5 hours, We got the plans from this site,

http://www.i4at.org/surv/soldehyd.htm

The other plan we considered was this one,
http://www.ag.ndsu.nodak.edu/abeng/plans/6244.pdf
we just felt that the one we made will be more efficient.

Photo set showing the building process

A very good bunch of articles on dehydrating

a couple questions I have had asked of me in the past
I'm planning on building a solar food dehydrator this year to make my own food for backpacking and other activities where weight and space are not an option. I have a couple of questions on this topic.

1. I have a pressure canner. How does dehydrating compare to canning, besides weight and space? i.e. does it keep as long ,etc?

2. After I dehydrate it is vacuum sealing a good idea?

3. I was told solar dehydration would not work in humid climates such as Georgia. I live south of Atlanta. My personal opinion is that's not true, if you have air flow.

My replies

1. dehydrating takes lots less space, is a lot less weight and last as long if not longer than canned stuff. For hiking etc dehydrating is ideal. Nothing can really beat it . Making hot, good for you meals from dehydrated veggies is simple and there is a lot you can do with them. It doesnt just have to be soups etc. I make stir fried rices and such quite often with our veggies. Throw them in with noodles or ramen and add a bit of meat. Insta-meal

2. If you are planning for long term storage it is a good idea. If it is just for one season to another of preserving, it isn't necessary unless you want too. I dont vac seal ours, just throw in a ziplock and use a straw to get the air out and things stay good from one harvest until the next.

3. poppycock. It works fine and i am up in north georgia in the katuah bio region. If you know the area , you know what our rainfall amounts are here a year... If not , we are just under rain forest amounts lol.The solar oven is actually a good way to dehydrate. If you have one built already can just make shelves and leave the lid open. If it is an open cooker just throw the stuff on a screen and dry them. Ours works very well. Most stuff drys in one day and on the rare occasion it takes more than one day, just bring whatever it is you are dehydrating in for the night. Pay attention to when rains are coming and you shouldnt have a problem. Just put the dehydrator where the sun is good and on it.. Indians and pioneers n such simply set what they were drying in the sun each day. It worked for them just fine... Tomatoes and bananas seem to be the hardest to dry proper. It just take a bit of trial and error on them. The high water content in the maters makes them a bit harder to dry. Romas and paste tomato are the best option for dehydrating.. Bananas , the sugar content makes them a bit awkward but it does work too...

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