July 22, 2014

An Experiment With Solar Dehydrating

I admit that I never thought solar dehydrating was a very good option for me. We have too much humidity. But when I ordered my solar oven, the preparedness accessories kit was too good a bargain to pass up. It included dehydrating racks, so I thought I might as well give this a try.

The accessories kit included drying racks and parchment
paper, as well as two enameled cooking post with lids. 

July is blueberry harvest so blueberries were a good choice for my first experiment. Solar cooking is a moist cooking method, so it is important to vent the moisture. This is done by resting the oven lid on top of the latches.

Latches used to vent moisture.

At night the lid is secured tightly, and the process is resumed the next day. The biggest challenge was keeping the oven temp low enough. Recommended dehydrating temperatures are 100 - 150° F / 38 - 65° C. If aimed at the sun, my Sun Oven easily reaches temps of 325 - 350° F / 165 - 175° C. Even aiming away from the sun didn't guarantee low enough temps.

Fortunately we had low humidity for several days. After 48 hours, the top rack had dried perfectly,

Blueberries after 48 hours in the solar oven/dehydrator.

but only the top rack. It took a couple more days to get the rest of them dried properly.

The biggest problem was that this tied up the oven for quite a few days. I use my solar oven every day for cooking, if there is sun, so not being able to was an inconvenience in that regard.

Humidity is a big factor for dehydrating here anyway. Even in my electric Excalibur I can't make crispy veggie chips; they start becoming soft as soon as they cool off. Things still keep however, which is good.

I think this experiment was successful enough that I would consider building a dedicated solar dehydrator in the future, rather than use the solar oven. There are some nifty DIY dehydrator plans here. I'm sure I'll have some spare time to do that within the next decade or so.


Anonymous said...

This is a really interesting post (as are many of your posts!) because it is the first time I've really seen an application for solar cookers for me. I live in the UK and I've always thought our weather was too unreliable to cook at safe temperatures in a solar oven even though I love the idea. But we might get temps that are good for dehydrating.

Of course I say that just as we are in the middle of an unexpected heat wave...

Dawn said...

I havent tried dehydrating berries, did you prick them first to help the moisture escape from them.

Leigh said...

Hi Becky! (I've already returned the blog visit :) Thank you! I do believe there is a solar cooking group in the UK. At least someone teaches it, but I don't have a link. I know the Sun Oven is available from Amazon UK. I'm interesting in how well my solar oven does during winter, when it's said one can still cook with it! We'll see and I'll report results here.

Dawn, berries are easy to dry. No, I don't prick them and probably would abandon the project if that were required. Too many, LOL. Mine dried rock hard, but I suspect they'll soften up a bot over time.

Dani said...

Leigh - I've tried dhydrating in my solar oven, and also find it gets far too hot. I've "singed" far too much to try that again, so am also making myself one. Unfortunately though, I CANNOT find formaldahyde / chemical free wood with which to clad the unit... :(

Unknown said...

I love your "Suck it and See" attitude Leigh. If it doesnt work this time, then try try again, learning each time. Such a good example.

Farmer Barb said...

Are you going to freeze some? Maybe you could do that to hold them and then dehydrate them when you are back to baking indoors. Another thing is another thing and I am having a very hard time just keeping down the acquisition of more things. I know that a hot, humid summer is a force to be reckoned. Good luck!

Sandy Livesay said...


Dehydrated blueberries YUM!!!!

Have you tried rotating the racks every couple of hours to help balance the dehydration process?

I've notice with certain vegetables and fruits, I had to rotate my racks this way everything processed about the same time frame.

Renee Nefe said...

can't wait to see your homemade solar dehydrater. I've seen them done with fans before.

For my herbs we are lucky enough to just stash them in the basement for them to dry out. In fact I need to go put the parsley in a container to get ready for basil and thyme...oregano is taking it's long sweet time. ;)

Harry Flashman said...

Living on a mountainside, with taller mountains all around me, solar power isn't an option here. We just don't get direct sunlight long enough, even in summer. I bought an electric dehydrater some time back and it works well making jerky. Wish I could have a solar one though.

~Bettie said...

"Within the next decade or so" Lol You sound like me with my project lists.
Each post of yours about your solar oven intrigues me. I hadn't thought about being able to use it as a dehydrator. I think I'll be asking for one for my birthday next year. :-)

Nicole and Andrew said...

wow you must have quite a few blueberry bushes. i would be very interested in seeing your diy dehydrator, i have not put much thought in about solar ovens but i think i will be researching them as an alternative cooking source.

Leigh said...

Dani, thank you for that! I found it worked best on overcast days, where the temps didn't get too high. And good point about the wood for building one's own.

Lynda, well, I can't stand waste!

Barb, I freeze gallons of blueberries. I did think about trying to dehydrate after defrosting, but they usually seem soggier, which would mean longer / harder to dry. I did discover this year that goats will eat them even frozen! I just finished making jam from the remaining frozen ones from last year.

Sandy, that's a very good idea. I don't have to rotate with the Excalibur so it didn't occur to me.

Renee, me too, LOL. I have had fairly good success drying herbs (chopped first) on the front porch with old window screens. Surely wish we had a basement!

Harry, one of the hardest things about this lifestyle is having to find what works best for oneself. Still, an electric dehydrator is a good investment.

Bettie, well, that's how it is! I've decided my solar oven is too busy to use for dehydrating, but it is very versitile.

Nicole, I have one old, huge one! It produces gallons and gallons of berries, which I share with the birds. :)