The following is an excerpt from Self-Sufficiency for the 21st Century by Dick and James Strawbridge (DK Publishing, 2010).
Few tastes compare to the stone-baked flavor you get from cooking in a traditional earth oven. They can be used for everything from bread and pizzas to pies. On an environmental front, the simple clay structure and use of carbon-neutral wood fuel makes cooking in an earth oven a low-impact option. The cost of building one is next to nothing, and the process, while a bit messy, is a lot of fun. (You may find it helpful to refer to this illustration of the authors’ earth oven as you follow the building instructions below. — MOTHER)
Earth Oven Materials and Tools
Clay (dig your own if possible)
Bricks or cinder blocks
Earth Oven Instructions
Build the Stand
1. Build a firm base. We used some spare cinder blocks. Keep it level and build the structure up to a comfortable working height for cooking.
2. Prepare a solid floor for your oven. It must have a smooth surface. We used a couple of old paving slabs.
3. Mark the center of the oven. Make it as large as possible. Ours is about 2 feet in diameter.
4. Draw two circles, one 3 to 4 inches inside the first, to show the thickness of the walls. Note the radius of the inner circle.
Prepare the Clay
5. Sift the clay to remove pebbles and debris if you dug your clay from the ground.
6. Lay a big tarp on the ground and mix your clay — best done with bare feet.
7. Add sharp sand (about a bucketful) and some water if the clay is very dry. Mixing takes time and effort. Don’t slip!
8. Keep turning and mixing the clay.
9. Test the clay to see whether it is ready to work with. Make a clay sausage.
10. Hold it with half in your palm and the other half dangling over your hand. If the clay bends but doesn’t break, it’s ready to use.
Make the Oven Base and Walls
11. Roll out a circular layer 1/2-inch thick on the internal circle of the base. Trim the edges with a trowel.
12. Wet the clay, then smooth it with your hands. This will serve as a smooth base for sliding whatever’s being cooked in and out of the oven.
13. Cover the circle with a layer of moist newspaper to stop any sand from sticking to it.
14. Pile on moist sand and sculpt the shape of the earth oven, making a dome that is a few inches taller than the internal radius of the oven.
15. Measure the height of the sand dome, which will be the interior height of your oven. Multiply this by 0.63 to get the height of the door.
16. Cover the sand dome with wet newspaper to stop the clay from sticking to it.
17. Shape the clay into sausages, then flatten and squash them into place. Start at the base and work around and up, to cover the dome.
18. Use the width of your hand as a rough measurement: the layer of clay should be around 3 to 4 inches thick.
19. Try to push the clay against itself, not against the mound of sand, as you add each piece. Cover the entire dome with clay, making sure it is still the same thickness at the top as the bottom. Wet your hands and smooth the surface of the finished dome.
Make the Door
20. Mark out the height of the door using measurements you made earlier. Our sand dome is 15 inches tall, so the door is just less than 9 1/2 inches in height. Mark the width of the door. Ours measures 10 inches — half of the oven’s internal diameter and perfectly big enough for a small pizza to slide in and out.
21. Draw the shape of the door freehand with a pen. Use a sharp knife to cut out the door. Do this in two sections, cutting down the midline of the door.
22. Slide the knife under one half of the door. Slide the excess clay out. Repeat for the other half of the door.
23. Cut away the excess clay on the inside of the door to enlarge it slightly. Leave the oven for a few days to a week.
24. Remove the sand when the walls of the oven resist denting when you poke them.
To repair any cracks that emerge on the oven as it dries: Wet the surface, then score it with a cross-hatch pattern. Apply more clay to the cracked area. Repeat if cracks appear after the oven has been used.
To fit a wooden door: Use a paper template to get the shape right. It doesn’t need to be a perfect fit, however.
Reprinted with permission from Self-Sufficiency for the 21st Century, published by DK Publishing, 2010.