Times are hot in Wisconsin. Between the humidity and the mosquitoes, it’s a jungle around here. What’s a cookie-lover to do? Turning on the oven would be madness. But living without mom’s pumpkin bread is unthinkable. Even cooking beans on the stovetop turns the kitchen sweltering.
What are some handy, precocious, apocalyptic survivalists to do? Harness the energy of the sun, of course!
A quick google search revealed a compendium of easy, inexpensive, and effective solar cooker plans from around the world. Primary materials range from old tires to cob to cardboard. There are plans for cookers, barbeques, and water pasteurizers. Models include the Suntastic, Primrose, Parvati, Dublin, and dozens more. I can’t help it, I think big: I choose the plan for the one called Heaven’s Flame.
The website details the materials, costs, and building instructions. The materials are simple: cardboard boxes, string, glue, foil, and a piece of glass. I collect free cardboard boxes from the local food co-op, measure the sturdiest, and call a local glass shop to order a small piece of double strength glass. It costs $6.50. Include the cost of tape and foil, and the whole shebang costs about $10. I pick up the glass and start to cut up cardboard. About two hours later, I’m ready to bake.
Detailed instructions can be found on the website, so I won’t recreate the wheel here. I further simplified the design to suit my needs and limited patience by using duct tape, and not bothering with some of the gluing and fabric edges. We also added some wool bits from old sweaters to the inside edges to better insulate and seal the glass top. The parts covered in foil (the collectors) reflect the sun down to the inner box, which is painted black. We put a brick inside to hold more heat and raise whatever we’re baking.
Notice: it DOES get hot! I haven’t put a thermometer in yet, but sources say the inside temp can reach into the 300 – 350 degrees Fahrenheit range. At this temperature, cookies, corn muffins, and mini pizzas only take a couple hours at most. Beans and rice can take all day (6-8 hours) to steam inside a glass jar. I like to start something in the morning and eat it for dinner. So far we’ve made cornbread, muffins, pizzas, rice, beans, lentils, corn and squash.
It’s important to adjust the angle of the box and direction of the collectors every couple hours for optimum sun exposure. It’s easiest to adjust it based on the shadow stretching out behind the box. The shadow should be directly in line with the box edges, with as little shadowed area inside the box as possible.
My second favorite part of the endeavor is all the curiosity the solar oven inspires. The best sun is in the front yard, so that’s where the solar oven sits, poised on a radio flyer wagon for easy moving. The pink duct tape and “transmogrifier” sign on its side attract the attention of neighbors, kids, and roadside construction workers alike. People ask what it is and how it works, how hot it gets and what I’m making, and finally, how they can make one themselves.
My favorite part is taking out my crispy corn muffins and lentil soup at dinner time and eating them in my nice cool kitchen where no oven has been used, no gas or electricity drawn. Food baked by the sun tastes like sun, like it retains the energetic components soaked right from the source. And when energy blackouts start rolling through Wisconsin, I’ll still be baking cookies.