A cob oven/earthen ovens is a wood firedoven made from a mixture of clay, sand and straw, that flavors and insulates way beyond masonry ovens. A cob or earthen oven can be used to bake bread, cook pizzas, bake cookies, roast veggies or anything you would cook in a conventional oven but with exceptional flavor and fun!
The word ‘cob’ comes from an old English word meaning ‘lump’ or ‘loaf’. The wet cob mixture is used to build thick earth walls; the building technique is very similar to sculpting with modelling clay.
In this video we show you how to build an earthen oven. Wood-fired earthen ovens are easily documented all the way back the ancient Romans. Likewise, they are easily documented in archaeological evidence and first-hand accounts from the 18th Century. We show you how easy it is to build one. #townsendovens
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Part One shows how to prepare the base and dome mold for building a cob oven. This oven is 36″ interior diameter, so the height of the interior is 75% of that, or 27″ tall. The thermal mass layer is 4″ thick, plus a 6″ thick insulating layer over that, so the whole oven is 10″ bigger than the fire cavity all the way around. The base is made with stones gathered from the site and held together with a clay + sand (cob) mortar. Also note, the primary reason to use firebrick is that they do not crack under the heat of a fire. For more information on cob ovens, I recommend Kiko Denzer’s book “Build Your Own Earth Oven”…it’s a complete “how to” including how-to sketches, list of tools, inspiring photos, and much more.
Part Two shows how to mix & install the cob thermal mass layer (no straw) and the insulating layer (lots of straw). Note that our soil was about 50% clay and 50% sand content. We want about 25% total clay, so we added an additional 2 parts sand for each 2 parts soil. Since the soil is already 50-50 sand-to-clay, the total is 1 part clay to 3 parts sand, or 25%. The thermal mass layer has no straw. This is the layer that gets hot and holds the heat from your fire. The second layer has tons of straw…basically as much as you can mix in. Straw is a good insulator, so the second layer helps hold in your heat. For more information on cob ovens, I recommend Kiko Denzer’s book “Build Your Own Earth Oven”…it’s a complete “how to” including how-to sketches, list of tools, inspiring photos, and much more.
Part Three shows how to carve the door, remove the sand, fire up the oven, and bake a pizza! This oven is 36″ interior diameter, so the height of the interior is 75% of that, or 27″ tall. The thermal mass layer is 4″ thick, plus a 6″ thick insulating layer over that, so the whole oven is 10″ bigger than the fire cavity all the way around. For more information on cob ovens, I recommend Kiko Denzer’s book “Build Your Own Earth Oven”…it’s a complete “how to” including how-to sketches, list of tools, inspiring photos, and much more.
Part Four shows how to apply a lime plaster to your cob oven. Lime plaster is made with 3 parts mason’s sand and one part lime putty. I use Mississippi vertical hydrate lime, purchased as a powder, and I let it soak in water for a minimum of 6 weeks, until it is the consistency of sour cream. The longer it sits in water, the creamier and nicer to work with it becomes. LIME IS CAUSTIC! So be sure to wear protective clothing and gloves. Never touch it directly! My lime plaster bible is the book “Building with Lime” by Stafford Holmes and Michael Wingate. You can also keep your oven dry with a roof or with clay plaster. Clay plaster will perform better in weather if it has wheat paste or manure added to it. Either way, plan to spend an hour or two repairing the clay plaster once a year.
Part Five How to build out a lip around your cob oven doorway so the door has a stop to rest on. This makes it easier to open and close the oven and creates a nicer seal around the door to keep heat inside.
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A few weeks ago, we attended the Gathering at Five Medals in Goshen IN. We went with an experiment in mind – could you make a mud oven from scratch at an event and bake in it the very next day? You are about to find out! #townsendsonedayoven#townsendovens
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This isn’t a tutorial – it’s mostly for friends who have asked for the story of how I made my cob oven. (I know it’s long – if you want to breeze through, you could play it at 1.5x speed and it’d be totally legible. I talked pretty slowly throughout.) Here is a link to the Kiko Denzer book that I mention in the video: http://a.co/3VfoBk4
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In this video of mud oven Shihab Kader demonstrate how to build a simple Home friendly cob oven with fire chamber below., so that it’s easy to clean the baking platform. Contact Shihab : 7025588535 mail id – myid.shihab@gmail.com
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This wood fired cob oven was built in part through a Permaculture Design Course in San Diego at Higher Elevation Permaculture.
