Scot’s Product Review: SUNFLAIR Solar Oven

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I think I’m on to something– solar cooking. I’ve been interested in it for a long time but never got around to doing much about it. Writing for SurvivalBlog gave me an excuse, actually a duty, to check this subject out. I plan to do at least two reviews on solar cookers and hope to do more since there are a variety of them on the market. You can also make your own, and I’ll look into that, too.

Why solar? Well, being able to cook without requiring fuel is huge. Not only can you cook, you can make water safe and dehydrate food for preservation. If you wish, you can work it into your daily life, which is a pretty good idea as you will then be ready to use it, should things go north (I’m Southern, going “South” is GOOD.) What I’m saying here is that if you have a solar cooker, you can store less fuel and gather less firewood. Neat, eh?

There are roughly three types of solar cookers I’ve discovered so far. The panel style, which consists of reflective panels that catch sunlight, may be the most common. They are usually the most economical. They are best used with a glass bowl around a cooking pot, which helps trap the heat so you can get faster cooking. Then, there is the box type solar oven that had a clear cover over a cooking box to help trap and retain heat. There are reflectors that usually fold up that catch more light and heat. Finally, there are parabolic ones that look like satellite dishes covered with mirrors. They focus the light onto the bottom of a pan, and their proponents say they are hot enough to fry with. I haven’t been able to try one yet, but I expect they are right about being able to fry.

One comparison I’ve heard made about the styles of cookers is to consider the parabolic ones the equivalent of a stove-top burner, while the panel and box style ovens are kind of a cross between a crock pot and conventional oven. The temperatures you see in the panel and box styles range from 200 to 350 degrees. For a point of reference, a crock pot usually cooks at 200 degrees on low and 300 degrees on high. Conventional ovens generally go to 500 degrees or higher and usually have a broil setting that is even hotter and browns meat nicely. The inability to brown meat in the panel and box style ovens are a shortcoming, but you can still cook things through and through.

There are, since life is two-edged, some limitations to all this. God doesn’t give us a free lunch, as we don’t deserve it. First, it really helps to keep these things aimed at the sun. That means every thirty minutes or so, one should check them and re-aim. You can aim them at a mid-point and leave it alone, but they will cook faster if you keep aiming it. The less efficient the cooker, the more critical this becomes.

Second, the panel and box oven styles take longer to cook than using a conventional stove. I mentioned crock pot, and you probably know those take longer too. On the other hand, many foods come out far better when cooked in a crock pot, so this trade-off is pretty much a wash.

The real issue, however, is that you have to have sun. Well, duh. Cloudy, rainy days won’t work. With my perfect sense of timing, I started this endeavor while the local weather has featured midday cloudiness followed by thunderstorms. Midday happens to be the peak time of day for solar cooking, so this has been a major bother and has slowed down my testing.

Location does matter with solar cooking. CantinaWest, a solar cooker dealer, has a map that shows the best locations. The main idea is that the farther south you go, the better it gets, though I’ve seen accounts of using them successfully in Canada during the winter. A big key is that the more sun a location gets and the fewer clouds, the happier you will be. I would bet that a northern desert would be better than a southern rain forest. That makes me, for once, jealous of my friends who live in the desert.

Although midday is the prime time to gather sun, I discovered that it is very smart to get the cooker out early. Preheating, just as with a regular oven, helps cooking. I got a lot more heat at 9 AM in my location than I expected and by waiting until 10 AM, I lost a lot of cooking time. I finally figured out that it worked best to get the oven out at 8 AM and start cooking at 9 AM. This also helped me beat the midday cloudiness and early afternoon thunderstorms that have been plaguing me.

As with any cooking, you have to watch the cooking temperatures. Foods must reach a certain temperature to be safe to eat; the temperature varies from food to food. I decided I needed a thermometer to measure what was happening to the food inside the oven. Since opening and closing them makes you lose the precious heat your cooker has collected, I found one that has a probe on a wire, so the delicate LCD display could stay outside while the probe is on the inside stuck in the food.

There is also the matter of a safe cooking temperature. If the temperature in the oven were to dip too low, bad things could start growing. I am very paranoid about food poisoning and like to keep the temperature in the oven above 200 degrees when cooking meat. It should be perfectly safe to dip a bit lower, but I want it to cook quickly enough to be sure nothing can spoil. This obviously means you have to pay attention to your oven and requires that you have a thermometer in the cooking area as well as one measuring the temperature of what is being cooked.

The first cooker I got my hands on was the SUNFLAIR Solar Oven. It is available in two versions, the $140 one I tested and a $100 version that has fewer accessories.

When I opened the box the SUNFLAIR folks were kind enough to send me, I was really surprised at how compact and light the oven is. It is made of a material that is similar to the sunshades you can buy for your car’s windshield. It is shiny aluminum on one side and covered with a sturdy green fabric on the other. It has a layer of insulation in between the two sides. The oven itself folds up into a 2″ x 15.5″ x 19″ package that slips into a carrying bag. There is a sturdy clear plastic panel that zips shut to hold the heat in when you refold the oven into its cooking form.

You also get two racks, two flat pans, a thermometer for the cooking area, along with three pots. One of the pots is a steel Granite Ware 3-lb. roaster with lid, which should hold a chicken. The others are made of silicone, and what’s very neat about them is that they fold flat. They are smaller but big enough to be useful.

The silicone pots will hold a quart, but that makes them very full. Remember that they fold and you can accidentally fold them with food in them, so be careful. The lids fit reasonably tight. The Granite Ware one will hold two quarts with a bit of space to help avoid spills. The oven will hold two of the silicone pots and one of the Granite Ware.

The cooking thermometer is very helpfully marked in zones, indicating the temperatures for safe cooking, water pasteurization, holding food warm, and the temperatures where food can go bad.

They also sent me a WAPI, which I’ll write about a little later.

The component weights (in ounces):

  • Oven inside its carrying bag- 20.0
  • Rack- 13.3
  • Pan- 8.0
  • Granite Ware Pot- 21.5
  • Thermometer- 1.5
  • Silicone Pot- 8.0
  • WAPI- 0.3

My first thought was how great this would be for backpacking or camping. I would leave the steel pot behind for hiking, mainly because of its bulk. The rest of it will fold up quite flat and could easily be bungee corded to a pack. Very slick. I would carry the oven, the rack and pan, two of the silicone pots, the thermometer, and the WAPI for a total of less than four pounds. All of this would fit into the carrying bag, which is 15”x20”x3”.

After messing with it in the house, I took it outside to try. I decided to do something simple for my first effort. I cooked water. Seriously, cooking water has a serious purpose. It kills whatever bad bugs might be lurking, hoping to make you sick. One of the nice things I learned from researching solar ovens is that you only need to hold water at about 160 degrees Fahrenheit to sterilize it. This is called pasteurization (after the inventor of the process, Louis Pasteur). I had thought that water had to be boiled for several minutes, but it turns out the reason they say boil it is to make sure you keep it hot long enough to make it safe. Boiling does that and provides a visual indicator, but you can achieve the deed without boiling. For this, a solar oven works quite well.

How, however, does one make sure you got it hot enough without the telltale bubbles you get from boiling? Well, there is a cool gizmo called a Water Pasteurization Indicator (WAPI.) The SUNFLAIR folks were nice enough to loan me their version of the WAPI. It is a little vial that has wax in it that melts at the correct temperature. Once the wax melts and flows to the other end of the little vial, the water is pasteurized. I do need to point out that it still may not be safe. You have killed the bugs, but there could be chemicals or other things in it that are bad for you. Filtration may still be necessary.

Something I really like about the SUNFLAIR WAPI is that it is attached to a wire with weights on each end. This allows you to easily suspend it in the center of a container of water so you can be sure it reflects the temperature at the core of what you are pasteurizing. You can also make sure the end with the hardened wax is at the top so you can be sure when it has melted and shifted to the other end.

I started using the pots to treat the water, but then settled on canning jars. They aren’t the most efficient for absorbing the sunlight, but they do work, and you can put the WAPI in one and watch for it to melt.

Once I discovered that I could cook water (which may have surprised my wife), I decided to try something else really simple– yellow rice. That’s a staple here. I got a reasonable amount of sun that day (though there were clouds), and it cooked in about three hours. I didn’t do it quite right though. I should have used the flat black pan under the pot. It probably would have cooked a bit faster that way. Nonetheless, it was fine for dinner.

Baked potatoes have been a big hit. On a day with very intermittent sun and some thick thunderheads going by, I managed to get four of them almost done in about five hours. I had to dash to bring the oven in, though, so a thundershower didn’t get it. We finished the potatoes in the microwave with about two minutes of cooking and the consensus was that they were better than ones that were cooked completely in the microwave and possibly better than oven cooked. My wife, who is a seriously good cook and appreciates food a lot more than I do (it’s just fuel, right?) pronounced them quite fine and really liked how fluffy they were.

On another day, which also had a lot of clouds interrupting the sun but no thunderstorm, I managed to completely cook four potatoes in about seven hours. If I could just get a day with continuous sun, I am sure they would cook completely in far less time. Again, they were much nicer than microwaved potatoes.

I also cooked carrots and turkey breasts in the oven. By starting early, I managed to raise two breasts to 189 degrees in two hours. This is well above the safe cooking temperature for turkey. They were in the Granite Ware pot and came out moist and tasty, having cooked in their own juices. The carrots, surprising to me, took a couple of hours longer, but I cooked them in one of the silicone pots, and I don’t think they are as efficient as the metal Granite Ware ones.

I wasn’t very happy with macaroni and cheese, but a common complaint about solar ovens is how hard it is to cook pasta. I’m going to keep trying as some insist it can be done and done well. My first effort produced a kind of pasty goo. My son rejected it, though I had it for dinner and the chickens loved the leftovers. I’ll report back if I manage more success.

I aimed the SUNFLAIR by its shadow. It has two flaps that stick out from the sides, and by keeping their shadows even it seemed to keep it aimed. I also tilted it back a bit when the sun was high at midday. You have to be careful when you do this as you can tip things over inside the oven. Keeping it aimed helped keep the oven temperature higher and more consistent.

The highest temperatures I saw inside were around 275 degrees, but it was very hard to keep it that hot. It was more commonly a bit over 200 degrees, which puts you at crock pot temperatures at the low setting.

SUNFLAIR says that crock pot and Dutch oven recipes adapt well to solar cooking. I found that to be true. It’s great for stews, which my family enjoys, though my son says not to put peas in it. Sigh. If you do add vegetables over the protests of the children, add them later as they take less time to cook. The Granite Wear pots stack, so if you get an extra, you can cook the peas separately and the adults can add them to their servings, so everyone is happy.

I was very surprised at how much moisture is released in cooking. You can see it as it condenses on the inside of the clear cover. Solar Flair suggests slipping your hand in and wiping it off with a rag. I think this helps keep the temperature inside higher. Although opening the cover does release some of the trapped heat, I think the moisture is blocking the sunlight, so the tradeoff is worth it.

Wind is a problem. This cooker somewhat resembles a sail. I only had it blown over once, but I was using it in a fairly sheltered area away from wind. SUNFLAIR suggests using rocks to weight it down, and that’s a good idea. It also occurred to me that rocks might help retain heat when a cloud passes over the sun. I would probably wrap them in something to protect the oven, as they might abrade or damage it. I also suspect that wind could lower cooking temperatures.

I’m not sure about operational security with a solar oven. They reflect light. I think that you can reduce how visible they are to people at ground level by being careful. If you use it inside a fenced area or in a clearing surrounded by trees and bushes, it would help. If someone is above you, however, there will be angles from which it is highly visible. You have to consider what you are dealing with.

After spending some time with this, I want it for several reasons. First, it is fun to use. Second, it is going to be a hit with my Scouting community. Third, it is a way to help my family, should there be a disaster. It would reduce the amount of fuel we need to store, and it means we can purify water from the lake we live on. We can carry it with us if we ever had to evacuate on foot. If we leave by car, it takes up very little room, so we can carry more supplies.

I did a lot of research on solar cooking, and some of the websites I found useful are:

– SurvivalBlog Field Gear Editor, Scot Frank Erie

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