Wednesday, August 27, 2008

SOLAR OVEN COOKING

We found a solar oven from Sun Ovens International that we hoped would be perfect for cooking in our tropical weather in Hilo, Hawaii.

Our hope was that a solar oven would allow us to cook most of our meals without electricity or propane, in other words, free cooking using the sun.

Global Sun Ovens are hard to get since the company is backlogged manufacturing them for African countries with the goal of saving trees and providing a solar method to pasteurize water.


We found one online at a lawn and pool supply shop in Virginia and convinced them to mail it to Hawaii. We paid $209.99 for the solar oven and $66.25 for postage.


Setting up the oven was easy. It popped out of the box and was quickly ready for use on our porch. The four reflective flaps can be pointed to the sun. The interior chamber is painted black to maximize the heat and covered by a glass door. A thermometer is easily visible through the glass cover to monitor the temperature inside.


We left the oven outside to cure the paint for a couple of days. We brought it in at night and when it looked like it might rain. The stove is very portable, folding into an easy to carry cube.

Figuring out how to actually cook something in the solar oven was another matter all together. The oven comes with no instructions and no web site recipe support. You are on your own to figure out how to harness the sun and convert digital temperature controlled recipes into recipes using analog temperatures that vary based on the time of day, clouds and wind.

The oven usually attains temperatures lower than standard cooking settings for most recipes in a regular oven (350 oF). Between 11AM and 2PM the air temperature in the solar oven chamber is about 270 oF and the temperature of the food and water (measured using an electronic cooking thermometer) was about 175 oF. We did notice that after using the oven many times, the temperature in the chamber seemed to get hotter. It is possible the days were just sunnier than the days during our initial cooking attempts.


Our first successful cooking project was an egg. After some searching we found a suitable pot that was non-reflective and dark colored.

After waiting for the oven to heat up, we put an egg into the pot which had been previously spayed with oil. We covered the pot and timed the cooking, checking after 3 minutes and again after 6 minutes.



After 6 minutes, the egg was very well cooked. It looked different than an egg cooked in water (poached) or fried. It was completely dry and white.


We had good luck cooking baked potatoes and rice. They don’t seem to mind how long they are in the oven. So if a cloud passes by and reduces the temperature, the potato and rice are not impacted other than taking longer.

We had no luck cooking pasta; it remained hard and then turned to mush. It is a challenge to cook food items that require boiling water for short cook times. We tried drying foods and as of yet haven’t figured out how to keep them from turning into inedible leather.

We used a non-reflective tea pot to cook water for tea. The maximum temperature we could get the water was 174 oF. This temperature pasteurizes water, but is not our usual method of using boiling water to make tea.
When the temperature refused to go higher, we poured it in a cup and made a great cup of tea using a tea bag. Not having boiling water didn’t seem to impact the flavor.


The success of the cooked egg and tea, gave us the confidence to try something a little grander. We mixed up some biscuit dough and popped it into the pot for 20 minutes. The results worked out well – though there was no browning, so we had to cut into it to determine if it was cooked. We then tried cooking a biscuit on an uncovered dish, and we were rewarded with a dryer version of the cooked biscuit.

We have found some challenges with the oven, like needing sun glasses when around it to keep from being blinded by glints of lights from the reflectors. And we need serious heat resistant gloves to keep from being burned while moving and shifting pots in the oven. We rely on testing and sticking a portable food thermometer into the food to determine if it is done. The food doesn’t always look the same as it does when done in an electric oven or stovetop.

We have many other food projects planned for our solar oven like peanut butter cookies, muffins, and bread. It is exciting to be able to cook these things during the heat of the day, without heating up the kitchen from the oven. Not to mention it is completely free!

3 comments:

ben said...

You can build a Fun-panel solar cooker in less than an hour from a cardboard box and a few metres of aluminium foil.

Tom Sponheim
Solar Cookers International

Tracy said...

Great job giving your new solar cooker a try. I am in Oregon and have started using a solar funnel I made out of cardboard and foil several weeks ago.

I'm sure you will find that your oven is much more user friendly and efficient then you imagine now.

I look forward to reading more about your results, maybe I can learn from them and get more out of my own experimentation.

To date I have made bread, cake, chicken, chili, soup and stew. Soon I will make an oven to try out things that need more heat.

Tracy

Gloria said...

Aloha,
I have just purchase the solar oven. It is wonderful. If you know anyone who would like to order one, they may contact me at hawaiisolarovens.com
Mahalo.
The price has increased, it now is $299.00 plus $85.00 for shipping