Making a backyard mud or clay oven is a great family project, and once completed, you will be able to make fantastic hearth breads, and professional quality pizza. A mud oven is a wood burning oven, which used the residual heat from the firing to cook with.
A basic backyard oven can be made for next to nothing, and will be a very satisfying project for the whole family. There will be lots of mud and squishing and stuff; and kids will definitely enjoy the process.
A cob or clay oven is vastly superior to your conventional oven for pizzas and bread. The massive radiant heat that is stored in thick mud walls will deliver deep crusts to your bread, and you can keep a live fire going to make fantastic pizzas in about 3 minutes! You can never get your home oven hot enough to really make a great pizza, but your wood fire mud oven can get seriously hot.
The steps as follows are a pretty basic guide, and if you get inspired, you can visit the links at the bottom the page for more information.
Basically all you need is sand, clay, and hay. The hay serves as insulation, so if you have another insulation that you’d prefer to use (rice hulls, cellulose etc.) you can substitute for the hay. The hay should be chopped small, for easier mixing.
You are going to make the oven using to different mixtures of “mud”. The outer mixture, under and over the oven, will be a very light mixture, using as much insulating hay, and as little sand and clay as possible, and the inner layer, will use no hay, and be a heavy and dense mixture, perfect for heat storage.
To start, make a fire proof platform for your oven. It is easier to use if you raise this up to at least waist height, but you can certainly do it on the ground if you’d prefer to simplify the project (that’s what I did!). A good base for the oven is a layer of rock. On top of this lay about 8 inches of clay/sand/hay mixture. You want to use as much hay as you can, but the mixture must still sort of stick together. Clay and sand should be added in a ratio of 4 parts sand, to one part clay.
The mixing of this is both the fun part, and also the hard part. It is best mixed with your feet, ala squishing grapes for wine! Lay a tarp on the ground, and add your sand/clay mixture, and as much water as needed to make a thick mud. Keep adding hay until the mixture will no longer make a sticky ball. You should be able to take a baseball sized lump of this stuff, drop it from waist height, and have it still stick together.
Now for the hearth floor. You can either use a mud floor, or a brick floor. If using bricks, lay down a quarter inch of sand, and lay the bricks down until they exceed the oven diameter eventually wanted by a couple of inches. You can either use regular red bricks, or fire bricks. Red bricks should work fine, but fire bricks will last longer. Lay the bricks on their sides, to make the hearth floor about 4 inches thick.
If using mud, mix as before, omitting all the hay. You don’t want to add more than one part clay to the mixture of four parts sand, as the clay will crack when dried if there is not enough sand. Basically, use as little clay as you can get away with. Lay the “mud” down until you have reached the size wanted for the hearth floor. The mud floor will not be as durable as a brick floor, but if you are only going to be using the oven occasionally, it should be fine.
Next you want to make a mold of the interior dome of the oven. This is very easily done using wet sand. Make a mound of sand, and add water as needed so that it will all stay together. When finished, cover with wet newspaper all over.
The height of the oven is not really that important, as long as the height of the door is 63% of the height of the top of the oven’s interior. This ratio is quite important for correct airflow when firing your oven. If you don’t get the door/height ratio right, it will be a lot harder to keep a fire going inside the oven. For example, if your oven interior was 20 inches tall, then your door should be about 13 inches tall.
On top of the sand mold, lay about 4 inches of the clay/sand mud; don’t forget to leave the doorway free! On top of this mixture, add another 6-8 inches of the insulating hay mud.
Presto chango…you’ve made an oven!
It’s best to let the whole thing dry out quite slowly. The likelihood of cracking increases if you try to heat the oven to promote drying. After a few days, if you want to speed things up, you may light a few small fires in the oven.
The oven should be completely dry after a couple of weeks, and ready for use. Many people use a hardwood door carved into the shape of their door frame.
When ready to use, light a big fire in the oven, and let it burn for a few hours. Sweep out all the ashes, close the door and wait for bout half an hour and you’re good to go.
Alternatively, you can make pizza in the Italian style by maintaining a small fire in the corner of the oven as you cook.
Using your oven is another subject entirely, and beyond the scope of this hub!
The preceding information was a pretty general guide, and is only meant to demonstrate how conceptually easy and inexpensive the building of a backyard oven can be. They work very well, and your pizzas and breads will be the envy of the neighborhood.
Enjoy!