The Solar Funnel Cooker we demonstrate in this post is adapted from former Brigham Young University Professor Steven Jones’ unique solar funnel cooker design. It is inexpensive to make and simple to use.
How can you cook your food or pasteurize water without fuel when an emergency challenges your survival? A solar funnel cooker can be constructed using a glass jar, reflective material and an oven safe cooking bag. A few materials and a bit of knowledge and you have it made.
Solar Cooking Basics
Solar cooking uses the energy of the sun to cook your food and heat water. Check out our post Solar Cooking – Clean, Abundant, Free Energy to learn more about cooking with the sun. Solar cooking works best when the UV index is 7 or higher. Optimal times are between 10 am and 4 pm. Partly cloudy days will require additional cooking time. Foods rarely burn when left in a solar cooker like they do in a standard oven.
The great advantage to this little emergency cooker is it uses the sun for energy and it is inexpensive to make. The lid on the black canning jar acts like a pressure cooker decreasing the amount of cooking time required. It takes a little practice to learn how to use it well and take best advantage of the sun.
The solar funnel cooker will pasteurize water, cook stews, soups, beans, meat and even bake breads. Although I have to admit I don’t like the way the bread turns out. It comes out in chunks instead of nicely sliced golden loaves.
I prefer to use a solar box oven because it is much more convenient. However, knowledge is power. Understanding how to construct and use a basic solar funnel cooker may come in very handy someday.
Basic Supplies to Construct a Solar Funnel Cooker
The basic supplies needed to construct a solar funnel cooker include:
- 1-quart or 2-quart wide mouth canning jar with lid
- High temperature, flat black spray paint
- Large oven roasting bag
- Reflective material such as car sun shade or heavy-duty aluminum foil and aluminum foil tape (for ease when working with aluminum foil), or aluminized Mylar
- A support container which can be made from a plastic bowl or any thing that will support the reflector
- A wooden block or metal cage, anything that will support the bottle and keep it off the bottom of the container
The first step is to construct a reflector to intensify and direct the sun. You can use cardboard with aluminum foil glued to it, aluminized Mylar with shiny side in, or a reflective car sun shade to create the reflector for this cooker. Cut the reflective material into a 40” x 20” rectangle. Then cut a half circle in the center and punch three small holes along the bottom on each side. Insert one brad in each hole and fasten together so that it creates a funnel. It doesn’t matter which way the brads are inserted. The end result should look like a funnel similar to the photo in the center. The funnel pictured is made from an automotive reflective sun shade.
It is important to have air around the bottle on all sides, including underneath for optimal performance. We created this little support using wire mesh and pieces of coat hangers. The original design has the bottle sitting on a little block of wood. Airflow is better with the little cage, but either will do the job. The support container must be stable and support the bottle and funnel. Heat is not a concern as the only thing that gets hot is the black bottle. We used a plastic bowl and placed a piece of reflective material in the center to improve performance.
The base unit is put together by placing the jar support over the reflective material inside the support container. This design will support a one-quart or two-quart canning jar.
Spray paint the outside of a 1-quart or 2-quart canning jar and lid black with barbecue (high-heat) spray paint. Other spray paints will release toxins when heated. Hint: Do not wash in the dishwasher. I washed ours in the dishwasher and ended up with a dishwasher full of black spotted dishes. Allow to dry for a day or two before using.
Place the food item, or water, inside the black jar and screw on the lid. Place the cooking bag into the funnel and then place the jar on the wire support (or wooden block) and put inside the bag.
Blow air inside the bag to make the sides puff up so that the bag is not touching the sides of the jar. Tie the top of the bag with a twist tie. This creates a green house around the jar.
Adjust the funnel to maximize exposure to the sun. Periodic re-positioning may be required to follow the path of the sun. Stabilize the funnel on windy days by tying a string from each of the small holes in the top corners and staking to the ground. Use care when handling because the bottle will get very hot. The cooking bag is reusable.
This solar funnel cooker is lightweight and portable. Consider purchasing the necessary supplies to keep on hand and experimenting with your design so you will be ready to cook with only the power of the sun.
Summing It Up
Solar energy is a fantastic way to stretch your fuel stores or to provide energy when you do not have fuel. A solar funnel cooker is not the most convenient cooking device, but it works really well and costs very little to make. Remember that solar cooking works best when the UV index is 7 or higher. Optimal solar cooking occurs between 10 am and 4 pm. Plan your meals in advance to make the most of the energy of the sun.