Monday, June 18, 2012

Solar shortcake

Friday was one of those beautiful Seattle days when the sun shown all day, the temperature soared up above 70 (18 c), and anyone visiting would wonder why we always seem to think it rains here. Time to break out the solar oven. I used to make a massive, box style oven every year. I would cut up two boxes and fit them inside each other, stick in insulating material, glue aluminum foil to cardboard to make a reflector, paint the inside black and glue a piece of plastic over the top. It would take two days to make and dry it, and then it would start raining again and warp the cardboard. At best, the oven would be large, cumbersome, and poorly made - more because I am a klutz than because of poor design.
Sun reflector for a car or truck
Finally, I gave up and went the easy route. It works just as well, and all the parts serve useful functions as separate items when I'm not cooking with them.

Component one is a sun shade for the windshield of a car. I used one for a Chevy truck - it's a bit bigger than the standard, but folds up neatly when not in use. Better yet, when you aren't cooking you can use it as it was intended, to keep your car cool.


I fold the shade around the keyhole opening in the middle, so that it forms a cone with the reflective surface facing in. This is my reflector, which will send sunshine into my oven.

It was hard to get a good picture of it because it was sunny out and the metallic inside was sort of blinding. You shouldn't look directly into your solar oven - it is reflecting sunlight, remember, and can hurt your eyes.

Once it is cooking, you should also treat the solar oven like any other oven, or you will burn yourself. I used to think of it as a sort of "easy bake for grownups" but it's not.
Next, I have my cooking equipment. These are lightweight black camping pots, a glass serving tray and Pyrex bowls.

The clear bowls and serving tray let light through, and trap the in heat. The black cookware absorbs light and heats up. It gets hot enough to hard cook eggs, boil water, and occasionally burn brownies.

When cooking with a solar oven, I think about size, color and material, both of my equipment and of the food I am cooking.

For example, dark colored things absorb light and heat better than light ones. A dark chocolate cookie will bake faster than a pale sugar cookie. Black beans cook faster than great northerns.

Water takes a long time to heat up. If I wanted to make a pasta dish, I would either cook the noodles on the stove and then bake a casserole in the solar oven (which seems a lot like cheating to me) or mix dry pasta with sauce and cheese, add extra water, and bake a long time.
Once I've assembled my cooker and put my food in it, I orient it toward the sun, or toward where the sun will be in an hour or two.

John Donne, in A Lecture Upon The Shadow, says:

But now the sun is just above our heads
We do these shadows tread
And to brave clearness all things are reduc'd

I don't believe him, because he lived in England when he wrote that, and would have been at an even more northern latitude than I am. The sun is never straight overhead here in Seattle, even on the solstice it hangs in the south part of the sky, 66 degrees above the horizon http://www.alicesastroinfo.com/2011/03/seasons-cheat-sheet/.
When I want the cooker angled directly toward the sun, I look for the point where its shadow is directly behind it and small. If I want it to point toward a future solar position, I first point it to the sun, and then rotate it toward the south. Because I pay attention to the sun, I've gotten pretty good at positioning.

I have learned that I do my best cooking in the morning and the first hour after noon. Donne's comment that "the first minute after noon is night" is an exaggeration, but it's not completely wacky.

I started this shortcake at 10:30 and "turned off the solar oven" at noon, by turning it to face out of the sun. The cake had a dense, sponge cake like texture, denser and moister than if I'd baked it in a conventional oven, delicious with June's first juicy strawberries.

I used a standard pancake batter, because I didn't want a very sweet cake. If I bake cookies, I use about 1/4 of a recipe and make one huge cookie out of the dough. We slice it like pie and dip it pointed end first into a glass of fresh goats milk. Summer heaven.

Before I go, I want to challenge those of you who live further south, or at a higher elevation than Burien, which is 47 north lattitude and near sea level. The sun works hard to shine on me here. It has less distance and less air to travel through to get to you.

Here, it is strong enough to make me a late breakfast of poached eggs, pancakes and coffee. What can it do for you?
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