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The sun also bakes: Get out of the kitchen and discover solar cooking

By Gwen Schoen
Bee Staff Writer
(Published June 13, 2001)

Before Robert Metcalf decides what's for dinner, he checks the weather report.

"If it's going to be a warm day, with plenty of sunshine and no clouds, it's a good day for cooking," says Metcalf, a microbiologist and professor of biological sciences at California State University, Sacramento.

Metcalf is not talking about firing up the barbecue. When the sun is out, it's a good bet his back yard will be lined with solar ovens of various types.

What's for dinner?

On the day we visited his east Sacramento home, a feast was roasting in the sunshine: a whole chicken, lentils, acorn squash, corn on the cob, lasagna, brown rice and, for dessert, egg custard.

"We've been cooking with solar energy for about 20 years," Metcalf says. "I've always thought it made sense to use a nonpolluting, free energy source, but now that energy bills are so high and everyone is afraid of the cost to run their air conditioners, this kind of cooking makes sense. Not only does it cook your food for free, but your house stays cool because you aren't turning on the range or the oven. And you don't have to stand outside tending a barbecue while dinner cooks."

Metcalf uses a solar box oven he made from a kit about 20 years ago. He also uses panel cookers called CooKits that are sold at the Sacramento-based, nonprofit Solar Cookers International.

A box cooker consists of two boxes, one inside the other, with a layer of insulation between them. The inside box is lined with foil and the top is usually glass. A box cooker will hold several dishes at once, and it doesn't have to be turned to face the sun. It is also large and heavy, so it's not as easy to store as a panel cooker.

Panel cookers are usually made of cardboard covered with a shiny material similar to foil. When unfolded, they make a clamshell shape. Panel cookers need to be turned toward the sun every hour or so, and they will hold just one dish, so they are not as convenient as the box cookers. However, they are lightweight and affordable. (See story at top of page for buying information.)

In Davis, solar cookers are familiar sights. Lorraine Anderson steps outside to check on the potatoes that have been roasting in her CooKit for about two hours. She lives in Village Homes, a community with solar design features, so cooking in the sunshine is a natural extension of her lifestyle.

Lorraine Anderson of Davis roasts potatoes and sweet potatoes in her much-used solar panel cooker, which is made of cardboard covered with a shiny material similar to foil. Such cookers can be made at home or purchased for about $20. Bee/Chris Crewell

"Not only is this a fun way to cook, it's also completely nonpolluting and the energy is free," says Rick Palkovic on the joys of using his box solar cooker. Bee/Chris Crewell

"What are you cooking today, Lorraine?" asks a young boy on a bike as he pedals past her solar cooker. In her neighborhood, Anderson is known as "the lady who cooks outside."

"Brownies are always a hit," she says as she slips the lid off the black roasting pan. The potatoes are already steaming hot and just right for mashing with garlic and butter.

"I'll take these to my friend Rick's home later," Anderson says. "He is cooking today, too, so we'll have a completely solar-cooked dinner tonight."

She is referring to Rick Palkovic, an electrical engineer who with Anderson wrote a cookbook, "Cooking With Sunshine."

At Palkovic's home, chicken breasts and corn on the cob are just coming out of a solar box oven.

"I moved here from the Bay Area," he says. "I took one look at the sun up there and said to myself, 'There must be a way to put all that energy to work.' Then I saw a demonstration on solar cooking at the California State Fair and I was sold."

After a few years of experimenting, he and Anderson began writing their cookbook.

"Not only is this a fun way to cook, it's also completely nonpolluting and the energy is free," Palkovic says. "It's also easy, because I put the food in the oven in the morning before I leave for work and when I come home, dinner is ready."

Even things like chicken?

"Yes. If I'm cooking chicken pieces, I might put them out frozen. By the time they begin to cook they are thawed," Palkovic says. "The really great thing is that food never overcooks because it slow-cooks like you might do in a crock pot. The only thing you have to be careful about is getting home before the sun goes down. Food needs to stay hot so it won't spoil."

Solar cooking is not a new technique. Swiss naturalist Horace de Saussure, widely recognized as the grandfather of solar cooking, made his first glass-covered cooking box in the 1760s. The French Legion used solar ovens in the 1870s, and solar-cooked food was served by a restaurant in China as early as 1894.

Metcalf, the Sacramento microbiologist, was introduced to the technique in 1978 when he heard about two Arizona women who invented the solar box cooker. Metcalf bought one and Mother Nature has been doing most of the cooking at his home ever since.

"Our first reaction was the same as most people's," Metcalf says. "It's magic. It really works. We were amazed. And as we got more comfortable with the technique, we really enjoyed using our solar oven."

Sacramento organization beams solar story worldwide

Solar Cookers International, a nonprofit organization based in Sacramento, was founded in 1987 by a small group of solar enthusiasts. Since then, SCI has become the world's information clearinghouse on cooking with the sun.

Though somewhat obscure in Sacramento, the midtown organization is known around the globe, judging from the thousands of letters it receives each year. Most are from people in developing countries who want to know how to make hot meals without burning valuable and increasingly scarce firewood.

The people who conceived SCI were solar-cooking buffs, including Robert Metcalf, a microbiologist and professor of biological sciences at California State University, Sacramento. Once the group got organized, it quickly realized the potential benefits of teaching solar cooking to people in developing countries where firewood is scarce.

Until 1994, solar cooking was done primarily in solar box cookers, which take a lot of material to construct. In 1994, SCI was encouraged to develop a solar cooker that could be used in emergency situations. The association developed the CooKit, which folds up like a book for transport and storage. It reflects sunshine onto a dark pot enclosed in a clear plastic bag that can withstand high temperatures.

In 1995, SCI took the CooKit to a refugee camp in Kenya where refugees often trade food for firewood, which compounds the problem of malnutrition. Today, SCI has programs in Kenya, Zimbabwe and Ethiopia, where it estimates that 8,000 cookers are in use.

Every CooKit sold by the SCI provides an additional CooKit for a refugee in one of the areas where the SCI programs are at work.

Solar Brownies

Prep time: 10 minutes. Cook time: 90 minutes. Serves: 9.

Because brownie batter is already dark, it's not as important to use a black pan with this recipe. A black pan will, however, speed up the baking time. Check the brownies for doneness after about an hour. The recipe is from "Cooking With Sunshine" by Lorraine Anderson and Rick Palkovic.


1/2 cup margarine or butter, melted
1 cup sugar
1 egg
2/3 cup flour
1/2 cup walnut pieces
1/4 cup cocoa
1/2 teaspoon vanilla
1/8 teaspoon salt


Combine all ingredients in a mixing bowl. Grease or oil an 8-inch square baking pan with a lid and pour in the batter. Cover the pan.

If using a box solar cooker, place the pan of brownies in the cooker and prop the lid open slightly to let the steam escape.

If using a panel cooker, place a brick inside a turkey roasting bag, then place the covered pan of brownie batter in the bag on top of the brick. Place the bag in the middle of the panel cooker. Place the panel cooker so that it faces the sun.

Check for doneness in about an hour. If you are using a plastic bag, unclip it to allow the steam to escape while the brownies finish baking.

Per serving: 266 cal.; 3 g pro.; 32 g carb.; 15 g fat (3 sat., 7 monounsat., 5 polyunsat.); 24 mg chol.; 159 mg sod.; 1 g fiber; 22 g sugar; 49 percent calories from fat.

Solar-cooked Margarita Chicken

Prep time: 10 minutes Cook time: 3 hours Serves: 4.

We were skeptical about cooking poultry in a solar cooker, but this recipe has become one of our favorites. This recipe is from "Cooking With Sunshine" by Lorraine Anderson and Rick Palkovic.


2 tablespoons oil
2 tablespoons lime juice
1 teaspoon honey
4 chicken breast halves, boned and skinned
1/2 cup finely crushed tortilla chips
1 can Mexican style stewed tomatoes, 14.5 ounces
2 tablespoons chopped, fresh cilantro
1/3 cup grated Monterey Jack cheese
Cilantro sprigs and lime wedges for garnish


Mix the oil, lime juice and honey in a dark pan with a lid. Roll the chicken breasts in the lime mixture and then in the tortilla chips to coat. Arrange the breasts in a single layer in the the same pan with the remaining lime juice mixture.

If using a solar box cooker, place the covered pan inside the cooker. If using a panel cooker, place the covered pan inside a heavy-duty plastic bag and clip the bag closed with a clothespin. Place a brick in the bottom of the panel cooker and put the plastic bag with the pan on the brick.

Bake the chicken two hours. Drain the tomatoes, then purée them in the blender with the cilantro. Pour the purée over the chicken, and sprinkle it with the cheese. Cover the pan and continue solar cooking until cheese is melted, about 30 minutes. Garnish with lime wedges and chopped cilantro before serving.

Per serving: 412 cal.; 58 g pro.; 12 g carb.; 13 g fat (4 sat., 4 monounsat., 5 polyunsat.); 145 mg chol.; 412 mg sod.; 1 g fiber; 5 g sugar; 30 percent calories from fat.

Cooking in Sacramento sunshine: A novice's account

By Gwen Schoen
Bee Staff Writer
(Published June 13, 2001)

As much as we had heard about solar cooking, we still were not convinced that cooking with sunshine was such a good idea. So we bought a panel cooker from Solar Cookers International and a small black roasting pan with a lid from the grocery store and set about doing our own tests.

The panel cooker comes with several heavy-duty plastic bags. You place the pan of food inside the plastic bag and use clothespins to hold the bag closed. This holds the heat around the pot. You can use the bags several times, and when you need replacements you can substitute turkey roasting bags sold at the grocery store.

The first lesson we learned is that you need to use wood or metal clips to hold the bag closed. Plastic ones, such as chip clips, melt.

Lorraine Anderson also recommended placing a brick inside the bag to help hold in the heat. That was another good tip.

Another thing we learned in our testing is that you really do need a black pan with a lid to do the cooking. Since we didn't always want to use the roasting pan, we purchased two metal cake pans and spray-painted them flat black. One pan served as a lid when it was placed upside down and held in place with wooden clothespins. That worked fine.

We started with lasagna because that's something we avoid cooking when the weather is hot since it takes a long time to bake in a conventional oven.

Following Bob Metcalf's instructions, we spread a small amount of bottled pasta sauce in the bottom of the pan, then layered uncooked lasagna noodles with cheese, fresh spinach, more sauce and slices of fresh tomatoes and onions. When the pot was full, we slipped it and a brick inside the plastic bag. Then we placed the cooker in the sunshine with the lasagna nested in the middle and we waited. In just a few minutes the pot was far too hot to touch without a potholder. In about three hours, dinner was done -- and it tasted great.

The next day we tried baking cornbread. Again, a great success. We followed our regular recipe but poured the batter into the black pan and covered it with the lid. The bread was perfectly baked in about 90 minutes, double the time it would take in a conventional oven, but the kitchen was still cool. We were even more impressed.

The next test was blackberry cobbler. Actually, we were expecting guests for dinner that night, but they canceled at the last minute. After we tasted the cobbler, we were glad they didn't come. It was too good to share.

With each experiment we gained more confidence. So we followed Anderson's recipe for margarita chicken, which called for dipping chicken breasts into a mixture of lime juice and honey, then rolling them in crushed tortilla chips. After about two hours in the sun, we poured in puréed tomatoes and sprinkled that with grated Monterey Jack cheese. We admit that we were a bit paranoid about cooking poultry in the sunshine, so we kept checking the temperature with the instant-read thermometer. Metcalf was right, the chicken heated right up to 175 degrees -- safe as far as we were concerned.

The chicken recipe was such a hit that we realized we needed another CooKit, one for the main dish and one for a side dish, such as beans or rice.

Now we're ready to tackle pot roast -- and maybe some brownies. Bring on the sunshine. We're ready to do some cooking.

How to put solar rays to work at your house

Here are some resources if you want to experiment with solar cooking:

  • CooKit panel cookers: These are available at Solar Cookers International, 1919 21st St., Suite 101, Sacramento, CA 95814. The office is open from 9 a.m. to 3 p.m. Mondays, Tuesdays, Thursdays and Fridays. CooKits are $20 each, plus $4 for shipping. SCI also has plans for making box cookers and panel cookers if you want to make your own. For more information: (916) 466-4499.

  • "Cooking With Sunshine": This spiral-bound book, by Lorraine Anderson and Rick Palkovic, is available for $10 at Solar Cookers International. Or write to Our House Publishing, 2505 Westernesse Road, Davis, CA 95616.

  • Web sites: This is the Web site for the Sacramento-based Solar Cookers International. You will find tips on solar cooking and plans for making cookers. There are photographs and ordering information for a variety of ovens. You will also learn about the group's efforts to teach residents of Third World countries how to use solar cookers as an alternative to cooking on wood fires. This site lists a variety of cookbooks for solar cooking. Ordering information is included. This site is filled with all sorts of helpful hints for cooking in sunshine. You will find a long list of solar cooker manufacturers and photographs of various types of cookers on this Web page. The photographs of various solar cookers on this Web page are quite interesting. Don't be intimidated by the cooker that's larger than a minivan. You'll also find a number of solar recipes and some great solar cooking and drying tips.

    Solar chefs tackle questions on hot topics

    By Gwen Schoen
    Bee Staff Writer
    (Published June 13, 2001)

    These frequently asked questions about solar cooking are answered by Robert Metcalf, a microbiologist and professor of biological sciences at California State University, Sacramento; and Lorraine Anderson and Rick Palkovic, co-authors of "Cooking With Sunshine."

    Q: Is solar-cooked food safe?

    A: "I can assure you that if I didn't think it was safe, I wouldn't eat it," Metcalf says. "Germs, viruses and parasites that cause illness if eaten are killed at 150 degrees. Food cooks at 180 to 190 degrees, so when it is fully cooked, it is also free of disease organisms. Solar cookers heat to between 250 and 275 degrees, so it is perfectly safe."

    It's only when the sun goes down, according to Metcalf, that you can have a problem. Then you need to refrigerate the food quickly or reheat it again to 190 degrees.

    "Once the sun is no longer shining on the cooker, you shouldn't let cooked food sit for longer than three hours. If food has remained between 125 and 150 degrees longer than three hours, it should be reheated to 160 degrees and held there for 15 minutes to destroy bacteria," Palkovic says.

    Q: How often can we use solar cooking?

    A: "In Sacramento, the solar season extends for eight months a year. Over 90 percent of the days in the five hottest months are perfect for this type of cooking," Metcalf says. "It doesn't even have to be a hot day. All you need is sunshine and no clouds."

    Q: What about dogs and cats? The food smells so good that surely they are interested.

    A: "Actually, they are afraid of the reflection and the heat," Metcalf says. "The only problem we have is during the winter when it's cold, the cats want to sit on top of the box oven."

    Q: Do you need any special cookware?

    A: "Ideally, you want to use a dark, lightweight, shallow pot with a lid," Anderson says. "Cast-iron pots are slow to heat up, but they retain the heat well."

    Q: Suppose you are at work and dinner is cooking away in the yard when a cloud goes overhead?

    A: "Food will continue to cook as long as you have 20 minutes of sun an hour," Metcalf says. "If you can be sure that the sky will stay clear, though, you can put in any type of food in the morning, face the oven to the south, and the food will be cooked when you get home at the end of the day."

    "Your solar box cooker should remain unshaded for at least four hours between 9 a.m. and 3 p.m. in order to cook the food," Palkovic says. "A good rule of thumb is that you can cook with sunshine whenever your shadow is no longer than you are. That applies to season as well as time of day."

    Q: Which recipes will work?

    A: "Most recipes that work for a crock pot will be just fine in a solar cooker," Anderson says. "Meats, fish, chicken, fruits or vegetables, which steam in their own juices, don't need water for cooking. Dried foods, such as rice or beans, are simply cooked in the same amount of water they'd need on a stove top. Fish is wonderful."

    Q: How long does it take to cook food?

    A: "It's roughly twice as long as cooking in a conventional oven, but it does take some practice," Metcalf says. "Eggs in the shell cook without water in about two hours. Pot roast takes about four hours, depending on the size. Lasagna takes about three hours. Your food won't burn because it's held at that constant, low temperature."

    Q: What do you need to get started?

    A: "You need five things: the solar cooker, a black pot with a lid, a big plastic bag large enough to hold the pot, sunshine and a brick," Anderson says. "Place the solar cooker facing the sun. Put a brick inside the plastic bag and the covered pot containing the food on top of the brick. Close the plastic bag and resist the temptation to peek inside the bag until you think it might be done."

    The Bee's Gwen Schoen can be reached at (916) 321-1146 or

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