When doing any project here on the farm we source material from the farm if at all possible. Alan and I had wanted an Earth/Cob oven for quite a while.Most instruction on earth builds or earth ovens, tell you to use straw as a binder or insulator.
The research we were finding was just making us put it off. It made it look like you had to BUY so many materials to go into making an oven. The order was to buy soil that contained enough clay and then buy straw...OR buy clay to go with the soil you have and then buy straw.
Alan and I have a love of the earth...all things EARTH! We had been involved in earth works or clay works for years and were intrigued by traditional process.
We had researched our Native American heritage in traditional fire pit firing of natural clays. So, we had already been experimenting with the soil that we had here on the farm. Then, that led us to search out our "English" heritage of working with clay. We were very impressed with the Welsh version of "clay work" and that their philosophy was in line with ours...USE WHAT YOU HAVE! We saw where they would use a soil with enough 'workable' clay and add fibrous organic matter to bind. They didn't say it had to be straw...so, Alan's next thought is why not pine needles?! The next step is try out the idea...make some test cobb/clom (this can be in the shape of loaves or balls).
We do not have access to straw but we do have plenty of pine needles. They need to be completely dried/aged...not green. These can be gathered up off the ground and stored for use throughout the year. In constructing our earth oven we used only soil from our property, which was a perfect ratio of clay and sand to make a workable "mud".
What is a perfect ratio? It could be near 2 parts clay to 1 part sand...but it is more about the feel and texture. You want a workable mud that will stick together when you try to make a ball or loaf without cracking but not too wet to be soggy. I use a large kitchen seive to put the soil through to get rocks and large bits out. This can be mixed in a wheelbarrow. I use a large kitchen kettle and large spoon to start the mixing and then mix with hands to form the building cobb. We find that mixing small amounts at a time is actually more productive than large amounts. When working with smaller amounts it is easier to mix more consistently. We do not mix with our feet, which some people do. We mix with our hands but do cheat by using gloves.
In our first layer of cobb/clom we used the clay/sand mud. The second, or outer insulating layer, we used the same clay/sand mud but added the pine needles to the mix. This must be mixed thoroughly and then made into a constructing shape such as balls or blocks (cobb/clom). We try to make each layer at least 3-4 inches in width. After the balls or blocks of mud are placed then, they need to be smoothed together. Do not leave any space or air pockets (this can cause cracking).
So, our earth oven build consists of salvaged and re-purposed cement/cinder blocks for the base. We used a layer of earth and collected glass bottles for insulation. We did not want a fire brick bottom to our oven. Again, we wanted to use something from the farm and something relateable to the "mud". Alan was able to find a huge rock that was flat enough to make a good bottom for the oven. This will also hold heat naturally.
Pine needles can be used in place of straw in any earth build you take on!
Susan Tipton-Fox continues the farming and preserving practices that have been passed down to her by her family. She presents on-farm workshops in Yancey County, North Carolina, and growing her on-farm agritourism by promoting "workshop stays" on the farm (extending the farm experience).
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