I was pondering what to write about this week that somehow connected to the outdoors and the hot weather we have been having. Solar cooking! Using solar energy to help with food preservation or preparation is nothing new, but with growing populations in areas of the world where fuels are scarce or extremely expensive, solar applications are getting another serious look.
In some parts of the world, primarily Africa where ruling parties seem to change monthly and tribal fighting is constant, solar cooking is not only for cooking daily meals but is also a safety issue for women. Wood is the primary fuel source and a woman outside of her village gathering wood is very likely to be raped and/or killed by warring factions.
One of the colleges I work with for my Outdoor University workshop series, asked me if I could develop a course on solar cooking for them that would be part of their world/social studies. I have done some very small scale “cooking” with a parabolic collector for years, but it seemed like a fun project and my research began.
There is written evidence of various cultures using the sun to dry fruits, vegetables, fish and meats back into the 1200’s. We know from historical data that the practice of sun drying food source dates back at least a couple thousand years.
Serious advancement of solar collecting/cooking began in the late 1680’s when a German physicist, E.W. von Tschirnhousen, started experimenting with large lenses and mirrors. In one of his experiments he made water boil in a clay pot. This experiment was first reported in a study of solar cookers in 1767 by French scientist, Horace de Saussure.
Saussure was the first to record an effort to cook food using the sun. He built a miniature greenhouse with 5 layers of glass boxes turned upside down on a black table and reported cooking fruit. He later built a cooker out of two pine boxes topped with 3 layers of glass, and later still added wool insulation between the two boxes. He predicted, “Someday some usefulness might be drawn from this device, for it is actually quite small, inexpensive, (and) easy to make.” Another French scientist by the name of DuCarlu, added mirrors to a solar box and reported cooking meat in one hour. This may be the first true solar cooker documented.
Around 1870, yet another Frenchman named Augustin Mouchot, devised a box/oven heat trap and concave mirrors to create a solar oven, a solar still, a solar pump and ultimately the first solar steam engine. He saw great commercial potential for this invention in France’s sun-rich, fuel-poor colonies in North Africa and Asia.
During the mid-1940’s, Dr. Charles G. Abbot, Secretary of the American Smithsonian Institution, was the first recorded inventor of solar cookers in which the heat collector was outside in the sun but the cooker itself was in the house, with heat carried from collector to cooker by oil circulating in copper tubes. The solar boiler in this unit was insulated and stored heat which allowed cooking in the evening.
The evolution of solar cookers continues. Today, flat panel cookers and parabolic cookers are distributed in many third-world countries by various aid agencies. Boiling water and pasteurizing milk. Solar ovens are very capable of boiling water and milk to kill bacteria, which is actually one of their primary uses. Several models are made for backpackers and those who wish to cook “green”.
The biggest drawback with a solar cooker is the time it takes to actually cook a meal. Two hours is about the minimum with most meat dishes. If you intended to cook something like a roast, it may take six hours or more, if the sun stays shining. While very “eco-friendly” in some people’s eyes, it is not yet a practical and dependable way to consistently feed yourself.
You can purchase simple solar cookers/ovens today for $25 to $100. Generally, you can make a meal for one to two people with these cookers. For bigger units that would feed a family or cook at much higher temperatures, you will pay $400 to $1000.
I developed a simple design I call a “cone cooker” with easily available items. It cost about $25 to put together. I have developed recipes for a solar pizza, soups, cookies and for jerky.
If you are looking for something to do on a hot day, try some solar cooking. Have a great time outdoors!