Lovin' My Solar Oven

Well folks, the heat is on! It's been three record-setting days of triple digit heat with at least 2 more to come, and I have to confess that my attention has been pretty fully absorbed with the wildfires here in Colorado. There are about a dozen active fires at the moment - one in particular right outside of Colorado Springs where CatMan grew up and still has many close friends. We've got at least three friends in the evacuation zone and several more at risk, so I'm kinda having a hard time thinking about much else.

Soooo... since we can't do anything about the heat (or the fires) I figured I might as well drag out the solar oven, and while I was at it, I decided to dust off this old post from one of my former blogs. Enjoy!

Lovin' My Solar Oven!

A number of years ago, a co-worker of mine came back from a vacation on the beaches of Mexico, filled with stories of how he and his friends had cooked up an incredible variety of delectable sounding meals in a solar oven. Solar oven?! I’d never heard of such a thing. He said it was really just a big box with reflective flaps that concentrated the sun’s energy. I was intrigued… amazed even. Could this really work? 

Having a long love affair with all things solar, and especially with all things that sound too good to be true, the solar oven went on my “probably impractical but I really want one” list. At the time, they ran about $300, and that seemed like a hefty price considering it was sort of a lark, plus that was about all I spent on my “real” oven!

A year or two later I mentioned the whole thing to CatMan. I was whining about how I really wanted one, but couldn’t justify spending 300 smackers on something so frivolous. He said he thought they were easy to build out of cardboard and aluminum foil! REALLY?!? Now it really sounded too good to be true!

And so the great solar oven project began! I found a web site with plans for all sorts of different models. After lengthy consideration (like about 30 minutes) I settled on a combination of the “Heaven’s Flame” and “Minimum” models.

I found my boxes, stuffed my newspapers glued my aluminum foil, and when the big day came to try it out… it was a total flop. The box was too deep, the sun barely reached inside it at all, the flaps wouldn't stay put, the thing hardly got warm at all… I couldn't bring myself to throw it out, so for years it sat in a corner of the basement junk room until I finally sent it to recycling last year.

"The Flop" - Well, we live and we learn!

Undaunted, I tried again. This time I decided to follow the plans for the “Minimum” box cooker to at T. The results were definitely better, but I still couldn't reach temperatures much above 200 degrees Fahrenheit (about 93 degrees Celsius).  Finally, after a few modifications (angling the opening downward, replacing the window with glass instead of plastic, and putting felt around the edges to make an airtight seal)… success!!!

My oven now reaches temperatures of  nearly 300 degrees Fahrenheit (about 148 degrees Celsius).

OK - It was hotter, but then steam formed on the glass and cooled it down a bit.

These days I seldom use anything but the solar oven to cook on hot summer days. It uses no energy, helps to keep the house cool, plus it’s the ultimate “something for nothing” achievement! The only “issue” it has is that once it gets hot enough to reach the boiling point, steam tends to form on the inside of the glass which blocks the sun from getting in. Usually by that point it’s time to check to see if things are done though, so I just open it up and wipe off the glass.

Steam on the glass means it's time to check it!

So here are some tips if you’re considering plunging into the solar cooking adventure.

1. Get an oven thermometer so you can measure the temperature in your solar cooker
2. An airtight seal is critical for the box style cooker. For me, that meant using a glass top and putting felt around the top edge of the box to create an air-tight seal.
3. Be sure to point your oven toward the sun. You may have to adjust it once or twice throughout the cooking process.
4. Remember… what fuels the oven is sunlight not heat. So you’ll get better results on a sunny cool day than on a cloudy hot one.
5. Cookware matters! The best cookware to use is something made of thin metal. It’s pretty much essential that it’s black. I’m using a few Graniteware pots that I got at the thrift store, painted with BBQ paint (black heat resistant paint that you can get at any hardware store). But only paint the outside! You don’t want to paint any surface that’s going to come in contact with your food.
6.     Always cook with the lid on - both because the black color attracts the heat, and because it helps keep the heat in the pot where the food is.
7. A black metal drip tray under the pot really helps to concentrate the heat. Mine is just an old cookie sheet painted black, elevated on a small metal tray to allow hot air to circulate underneath the tray.
8. You want to position the pot near the back of the oven so it gets as much direct sunlight as possible.
9. Sometimes tilting the oven can help to get more direct sunlight.

See the 2x4 under the back part of the box tilting it to let in more sunlight.

Here are a few things I've cooked in my solar oven recently. Happy Cooking everybody!

Solar cornbread - baked about 2 hours (the lid was on during the cooking process )

Roasted Chicken with Potatoes & Onions - cooked (lid on) about 3 hours

So has anybody else out there tried solar cooking? I’d love to hear what has and hasn’t worked for you!