A thought occurs to me now and then, when I turn on a burner and watch a ring of blue flame bloom underneath a pot: If I didn't have easy access to gas, electricity or even firewood, how would I feed myself?
There are millions of people around the world who have difficulty getting their hands on cooking fuels like wood or coal, let alone natural gas.
But a growing number of people are cooking with an abundant, clean power source: nuclear fusion -- or, in other words, the sun. This summer, I became one of them. Using some scrap materials and plans I found online, I built a solar oven whose temperature gets up to 240 degrees. It bakes potatoes, roasts vegetables and slow-cooks meat -- all while sitting on my front lawn on a sunny day.
Solar cooking is enjoying attention that it hasn't seen since the energy crisis and environmental awareness of the 1970s. People who are concerned about high fuel costs and climate change have embraced solar cookers as a super-efficient cooking technique. An added benefit: If you are cooking in the sun, you won't heat up your house on what is probably a hot and muggy Maryland day.
And those interested in international humanitarian work see solar cookers as a solution to deforestation, poverty and disease for people in developing countries.
"There are a number of us here and abroad who are trying to spread the word," said Pat McArdle of Arlington, Va. She retired from her job as a diplomat with the State Department last year and has become an evangelist for solar cooking in the developing world.
She had an "epiphany" about solar cooking while working in Afghanistan in 2005. She found landscapes that had been almost completely deforested and saw children who spent their days gathering scrub brush to cook the night's dinner.
She remembered that she had built a solar cooker when she was in the Girl Scouts. On a military base, she built a simple cooker from plans she found online, then brought it to a village. The skeptical locals were amazed when it boiled water. Now she lectures about solar cookers to people in the State Department, the Peace Corps and the U.S. Agency for International Development.
Nonprofit groups like Rotary International and Solar Cookers International, a 20-year-old organization based in Sacramento, Calif., have given solar cookers to people in countries such as Kenya, Ethiopia and Turkey, and recently to Darfur refugees in Chad. Solar-cooking experts estimate that there are about 1.5 million solar cookers in use around the world.
One of the first solar cookers -- a box with a glass top -- was created in 1767 by Horace de Saussure, a Swiss physicist and naturalist. He cooked fruit in it, but he didn't quite understand how it worked, according to an article about his experiments at solarcooking.org.
Today's cookers can be much more complex. There are parabolic cookers, which are large mirrored dishes that concentrate the sun's energy onto a suspended pot. These cookers get extremely hot and can bring water to a boil within a matter of minutes. On the downside, parabolic cookers are fussy and have to be turned constantly to follow the sun.
Others cookers are simple. The HotPot is a black pot inside a small, fold-out, reflective enclosure. Set it out in the sun late in the morning and it will cook all day. Advertisements say HotPots can reach 400 degrees, but people who have used them say that 250 degrees to 300 degrees is probably as hot as they get.
Commercial models abound online. The HotPot sells for about $100. The Sport Solar Oven, a box that holds two pots and is made from recycled plastic, is $150. The Global Sun Oven, which features a built-in thermometer, four reflective panels and a carrying handle, goes for $250.
I'm both cheap and adventurous, so I decided to build my own -- a simple solar box oven. Basically, it's a shallow box inside another shallow box, with a window on top. Insulation fills the cavity between the two boxes, and a reflective panel stands up on the back side of the oven, shining additional light into the box.
Before I started building, I consulted some instructions, tips and diagrams online. The Solar Cooking Archive, run by Solar Cookers International, is an excellent Web site (solarcooking.org), full of information. Then I went shopping. Solar chefs recommend using dark, shallow, thin-walled metal pots, like black Granite Ware. I bought two small Granite Ware pots at Stebbins Anderson in Towson, for $12 each.
I also purchased two cans of high-heat black spray paint, some weather-stripping, two sheets of clear Lexan plastic, a roll of aluminum foil, an oven thermometer and some assorted hardware -- including two L-shaped brackets. The most expensive item was a router bit ($35) that would allow me to cut a groove in a wood frame, where I would lay the Lexan plastic window. To build the boxes, I would use scrap wood and insulation that I had saved from various home-improvement projects.
My reflector would be a scrap bathroom mirror left from our home renovation. In the end, I spent $80.
It took me two days to build the boxes and window top, and I cursed my carpentry skills the entire time. I painted the boxes black, inside and out. I put weather-stripping on the underside of the window frame, to help lock in heat. On the sunny day I was building the boxes, I put one of the Granite Ware pots, with a thermometer inside, under the window in my black Toyota. Within an hour or two, the thermometer registered 160 degrees.
At 10 a.m. the day after the oven was finished, I put whole potatoes in one pot and tomato sauce, with raw garlic and basil, in another. I lined the sides of the box with aluminum foil (to let the light bounce around and hit the pots). Then I put in the pots and the oven thermometer, closed the window lid and set up the mirror.
I'll admit I really doubted this would work. But within an hour and a half in the solar cooker, the oven thermometer registered a little over 200 degrees. I turned the oven to face the sun about every hour throughout the afternoon and adjusted the mirror to let the light shine directly down into the box. At the end of the day, the potatoes were cooked through and the tomato sauce was a hot 220 degrees.
Vegetables were one thing, but the real test for me was meat. I bought 2 pounds of cubed pork shoulder and mixed it with chili powder, oregano, thyme and other spices. In another pan I mixed cubed beef with a small onion and a head of garlic with the top sliced off. I drizzled on a bit of olive oil.
I placed two baking sheets upside down at the bottom of the oven, figuring that would allow air to heat up underneath the pots. This time the oven hit 240, and after about five hours I found that the meat had browned and the garlic had roasted, as if it had been set under a broiler. I was stunned.
Keep in mind that a solar oven is not foolproof. I tried mine, filled with rice and chicken, on a partly cloudy day. The temperature never exceeded 165 degrees. The rice was lukewarm and uncooked. I threw the whole thing out. (Use an instant-read thermometer on the food itself. Never eat food from a solar cooker that has not heated up or has not cooked food through. If you do, you will get sick.)
Tom Sponheim, an expert at Solar Cookers International, says you develop an "intuition" for what will work in your sun oven. Your cooker doesn't have to be as big and heavy as mine, he says. Lately his organization has been promoting simple solar cookers called CooKits -- reflective enclosures made of folded cardboard, with a pot in the middle -- for use in the developing world.
This is a new world of food, so experiment, but understand the limitations of your cooker. It cannot deep-fry food. It can't roast a whole turkey. It was made for slow cooking, as languorous as the sun drifting across the sky. I think of mine as a fusion-powered Crock-Pot.
ONLINE Learn how to build your own solar oven at baltimoresun.com / solar
Cooking in the sun is an emerging, inexact science. But there are some basic rules that will help ensure success:
First, check the forecast. You need sun, especially between peak cooking hours of 10 a.m. and 2 p.m. A cloudy day -- even if it's hot -- will not work. But you may be able to cook on a sunny, cold day.
Be sure to monitor the temperature of your cooker with a thermometer, but resist the urge to open it and check the food. You will lose valuable heat.
Small pieces of food cook faster than large hunks.
Here are some Web sites where you can buy solar cookers, read about how to use them and get plans to build your own:
Solar Cooking Archive, including instructions on how to build an oven: solarcooking.org
Solar Cookers International: solarcookers.org
Solar Oven Society: solarovens.org
Sun Ovens International: sunoven.com
Solar Ovens and Sun Cookers: solarovens.net
Solar-Cooked Chicken Tajine
5 cloves of garlic, chopped (more if you like garlic)
1 tablespoon ginger
1 teaspoon cumin or 1/4 teaspoon saffron
1-2 teaspoons cinnamon, to taste
salt to taste
7-8 twists of a pepper grinder
3 large chicken breasts
1 large onion, cut into 8 pieces
1 zucchini (peeled or unpeeled) sliced lengthwise, then cut into 1/4 -inch pieces
1 large tomato, chopped
2 tablespoons chopped red bell pepper
1/3 cup of olive oil
1 10-ounce box of couscous
1/2 cup pine nuts
In a shallow bowl, mix the garlic, ginger, cumin (or saffron), cinnamon, salt and pepper. Put the chicken in the bowl and rub the pieces in the spices until they are all coated and the bowl is wiped clean. Put the coated chicken and the chopped vegetables into a lightweight black cooking pot. Pour the olive oil over the mix and stir to spread the oil around. Be sure that a few pieces of chicken are at the top of the mixture so they will brown. Put on the lid and put your tajine in the solar cooker. On a sunny day, it should take 3 to 6 hours to cook.
Prepare the couscous according to the instructions on the box. If you have a solar cooker that takes more than one pot, you can also heat up your water for the couscous. Toast the pine nuts in a toaster oven just until they're light brown (about 3 minutes) and sprinkle them on top of the couscous before serving.
Spoon the tajine over the couscous on each plate.
Note: With a solar cooker, cooking times can vary widely. Use a meat thermometer to make sure the center of the chicken has heated to at least 165 degrees, and make sure juices run clear.
Courtesy of Pat McArdle
Per serving: 869 calories, 68 grams protein, 37 grams fat, 5 grams saturated fat, 65 grams carbohydrate, 6 grams fiber, 152 milligrams cholesterol, 146 milligrams sodium