Solar Oven Winter Cooking Tips & Tricks
People often ask if a solar oven can be used during the winter months. The short answer is “yes”.
The longer, and better answer is: "Yes, and here are some important things that you can do to be more successful and get more winter solar oven cooking success."
There are important factors about both the design of the oven and how it is used that will determine the level of success you have using it in the winter. Here is a comprehensive overview:
Perhaps a bit less obvious is that the angle of the sun's rays is much lower than in the summer months, and why that matters.As you can see from the above graphic, in the winter the same amount of light rays (and potential heat) from the sun hit the earth, but are spread across a larger area.
What this means to a solar oven user is that fewer light rays hit the defined area where the oven is located than in the summer. That means less heat if no adjustments are made.It is important to note that even though outside air temperatures are significantly colder in winter than during summer months, that does not effect the ability of a good solar oven to produce heat.
For making heat, all that matters is how much sunshine arrives at the oven door. The next most important thing is retaining that heat. You have a lot of control there, by your choice of oven design and cooking methods.
Let's explore those.
An effective winter solar oven requires an easy way to adjust the angle at which it faces the sun. The design of the American Sun Oven is a good example of what to look for. I bought one 10 years ago and I was so impressed with its variety of uses and ease of use that I decided to make a business out of it.
It is made with an easily adjustable bracket on the back side, which allows the user to point it directly towards the sun, even when the sun is low on the horizon. The bracket is also designed to add stability to the oven. It also comes with a “sun-sight” that helps the user align the oven directly at the sun.
Large, well polished reflectors are also a must, as they effectively increase the surface area of the oven to gather and funnel more light into the cooking chamber.
Last, it is critical that a winter solar oven be well insulated in order to contain the heat that is generated in the cooking chamber. While, as mentioned above, outside air temperature is not a factor in determining how hot a solar oven can get, it makes a big difference as to how hot a solar oven cooking chamber can remain. That is why insulation and construction materials are so important to a winter oven. A poorly designed or made solar oven will lose heat faster than it creates it during winter use.
Winter Use Adjustments
Here are some easy tips for maximizing the potential of your solar oven in the winter months:
It is much more important during winter months to keep your oven rotated directly towards the sun. I like to set a timer on my phone to remind me every 20 minutes or so to go out and give my Sun Oven a little turn to track the sun. Remember, you want try to keep the oven door pointed directly at the sun as much as is conveniently possible.
Because the sun's path across the sky is much lower in the winter you will find less need to vary the “up/down” angle of the oven, but the "right/left" angle vs. the sun changes rapidly in the winter and it is very important to follow it closely. Set the “up/down” angle using the built in bracket if you're using a sun oven. If not, stacking bricks under the rear edge of the oven to reach the desired angle is fine.
Effective cooking time with a Sun Oven is generally from about 2 hours after sunrise to 2 hours before sunset. That means the shortest days cooking days, around the winter solstice, equate to a solar cooking “window” of about 9:30 - 3:30 in the Southern U.S, and 10:30 - 2:30 in the Northern U.S.. You can estimate the window in your location using those times as "bookends".
Those “worst case” cooking windows still allow plenty of time to heat the oven and bake a loaf of bread or a pie, or even a casserole. For cooking something that takes more time, like a roast or a chicken you need to strategize a bit.
Winter Tips and Tricks:
Don't store your oven outside when not in use. Keep it inside until set-up time, so that its materials are warmer when you begin than if you had left it out in the cold.
Get a wireless digital thermometer. There are many around for $20-30 that will monitor both the temperature of your food and the temperature of the cooking chamber, and deliver that info to you in the warmth of your home. Important bonus: A wireless thermometer means you don't have to open the oven door to check on things.
More on the best use of this shortly.
During the summer, each time you open the oven door while cooking adds about 15 minutes to the total cook time required. In winter months, you want to avoid opening the door at all once the cooking has begun. Remember, with the even heat produced by a solar oven, you don't need to stir your food while it cooks. It won't burn. Leave it alone.
Here is where you can extend your cooking hours a bit beyond the normal time window provided by the sun.
1) Set up your oven and get it pointed directly at the sun about 20 minutes before you plan to start cooking.
2) Use thin metal, flat black cookware in the wintertime and save the cast iron pots for summer, when you have more time for the heavy material to get warm. In the wintertime, the idea is to get things as hot as possible as quickly as possible, and then retain the heat.
3) Place your food in the oven along with the wireless thermometer.
4) Watch the temperature of both your food and the oven cooking chamber.
You want to see the oven temp fairly high, and either climbing or stable. Be proactive about rotating the oven to follow the sun as needed. Don't wait for the oven temp to start falling to do this. You'll lose momentum.
If you do these things, you should see the temperature of your food in the oven start to climb. Ideally, this will lead to your food being cooked perfectly with time to spare.....but what if you're cooking something that takes a long time, or you got a late start?
5) Keep a couple of old sleeping bags or comforters handy. If your oven is hot, but you're running out of daylight, or clouds are forming, go out and close the reflectors on your oven and cover it with the sleeping bags or comforters. You do this while the oven is hot enough to continue to raise the temperature of your food, but you are concerned that the cooking chamber temperature might start to fall and not be able to be restored to where it was.
Closing it down and covering it will go a long way towards retaining the heat that is already there, allowing your food to continue to cook. Remember, even though you're cooking something at an oven temperature of 350 degrees, you only need most things that you cook to get up to 170-180 degrees for a few minutes for it to be nicely done and ready to eat.
A roast is done “medium” at just 150 degrees. That can be accomplished even if it starts getting dark if you act quickly when you see the oven temperature falling, and you cover and insulate it. This is where the wireless thermometer is really a must.
Doing no more than the few tips just covered will make a major difference in your winter solar cooking results. You will find that after actually going through this procedure once or twice, it becomes habit and you'll just do it without looking at notes or even thinking about it. Pretty much the same as how you're cooking inside now.
It's hard to describe the enjoyment of bringing in a hot and tasty dish from the cold, wintry outdoors to a warm and cozy kitchen full of eager diners. I highly recommend it!