An earth or mud oven is another early cooking device.

According to Kiko Denzer, author of a how-to book on earth ovens, an earth oven is a dome shaped shell of mud and sand that can contain one to three layers – a dense thermal layer, a less dense layer with straw and a finish layer.

Denzer says to plan how big your oven should be by laying out the pans you will be using, such as pizza pans, loaf pans or cookie sheets.

The inner dimensions of the oven will need to be big enough to contain the pans easily.

Next, select a site, considering wind direction, wood storage, water proximity and roof protection.

To build the oven, you will need water, subsoil dirt (amount will depend on clay content), sharp sand to mix with mud, sand that holds its form for the oven form, straw if doing an insulating layer, wood for the door, newspapers and firebricks and standard bricks for floor, as well as bricks, wood, concrete or urbanite for foundation.

Do not plan to put a non-breathable finish (paint or concrete) on top of the oven. Denzer notes a nonbreathable finish will trap moisture that soaks back into the oven, possibly causing collapse. A roof over the oven with at least a three-inch ventilation gap is best.

Dig the subsoil dirt, which is a hard solid mass of earth that when dry is hard, not crumbly. It feels sticky and greasy when wet. Mix in the sand for a final cob mix of 75 percent sand and 25 percent clay.

To test for the right consistency, dampen the mix lightly, not paste, and listen to it crunch by squeezing. If you don’t heard it grinding, then add more sand.

Then, conduct a snow ball test. Make it dry, not too wet. Slowly pack the mixture into a firm ball. Drop the ball to the ground. If it holds its shape, it’s ready. If it goes flat, add more sand.

Put down the foundation, making sure that it will support the weight and be at a height to protect it from the elements.

Put down the brick floor.

Now, you are ready for the sand form. Draw a circle around the brick floor, fill it with sand, moistened enough to form into clumps and hold its shape. Shape it by walking a wooden board around and moisten with a light sprinkle of water until it is smooth and firm.

One thing to consider before preparing the dome is that the door must be 63 percent of the height of the oven for optimum baking. In addition, the dome height should be 60 to 75 percent of the dome diameter.

To make the dome, mix the ratio of sand and clay to form fine granules. Get all the clumps of clay out, by putting the dry mix on a tarp, and stamp and twist on it, working the clay and sand together. Roll the tarp back and forth over the mix until it looks evenly mixed. Add water slowly, mixing with the tarp again. Then, jump in and twist about, breaking up the clay.

Apply the mud in layers around the sand form. Press handfuls around the base and press down with thumb and fingers at least three inches thick, being careful not to damage the sand form. Use your hand as a guide. A thicker oven requires more fuel but it will stay hot longer.

When it is all covered, take your flat board and whack or tamp it until smooth and solid. To add another layer, rough this one up first. Then add straw, mud layer and then sculpt. Cut door and remove sand, remembering your dimensions.

(Information from the “How to Build Your Own Earth Oven: A Low Cost, Wood Fired Mud Oven; Simple Sourdough Bread; Perfect Loaves” by Kiko Denzer and Hannah Fields, available at amazon.com.)