March 2014 – The Clay Oven

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Richard Green built this incredible oven last summer which demonstrates how varied the designs can be. The use of an insulated layer, the lead work and then the outer layer of corrugated material are fabulous and add so much to the functional practicality of the oven. Awesome work Richard! Here’s what he had to say about it himself:

Obtaining the clay was an adventure. We went to Clayhaithe, north of Cambridge, which sounded like a good place to start. After a fruitless search for clay, I was sat by the river bank wondering what to do when a passing dredger stopped and pulled out half a ton of clay for me to fill my buckets. I weather-proofed it and added a bit more insulation. The only change with the next oven I make is that it will be bigger.

We’ve had great fun cooking pizzas, stews and all kinds of dishes. But on Boxing-day, we cooked a whole shoulder of pork for 25 people. It cooked for 14 hours and was magnificent. Thanks for all the help.

Thanks for sharing Richard – she’s a beauty! I challenge anyone to look at the picture, below, of the pork roast and not drool – even vegans! Best wishes, Simon.

: The chef doing his thing!

: Droooool!

While the rain continues unabated here in the UK, with no sign of sunshine on the horizon, I have decided to add a few posts which feature ovens from fans of the blog (and who have used, to some degree, my instructions to build their own). What I love more than anything is seeing how other people interpret the original design I posted – and end up with incredible looking creations of their own.

I’m kicking off with a really lovely, rustic looking oven built by Andrew Frazer who hails from Austin, Texas. Andrew came across the blog last year and ended up building his oven in July 2013. Luckily, Andrew has also provided an excellent narrative about the build process and some of the things that influenced the choices he made during the build. I’ll let him continue in his own words.

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My oven was built, this July, with the nearly pure clay that I struck about 18″ under the topsoil and the base is made from limestone rocks that I struck about 4″ under the topsoil! My earlier attempts to dig a garden and plant a couple of trees provided me with all of the free-stacked rocks that form the base. The oven sits on a 3-foot stack of limestone, in-filled with gravel. The oven is clay-dirt from my backyard, mixed about 3:2 or 2:1 with sand from the hardware store. The outer layers have added straw and the final clay plaster is 2 parts sand to 1 part clay dirt. The interior dimensions are 24″ circumference and 16″ high. Fires nicely and holds heat like a dream. Walls are very thick, I’d say 6-8″ in total.

The floor is not bricks but unglazed clay saltillo tiles. They have cracked heavily inside from the heat but are now pretty stable. My next oven will use bricks on the floor for sure. Under the tiles, I insulated with pearlite and clay slip mixed to about “rice krispie treat” consistency.

The oven was built up in this order:

6″ of drainage gravel under the first of the limestone rocks. The rocks are all from my backyard and stacked without mortar.
The interior of the base is filled with urbanite I found dumped in the woods behind my house (a bit of enviro-cleaning) and levelled with pea gravel. This gravel helps to lock everything in place.
Since my rock base was very irregular on the top, it is capped with an inch or two of cob.
The next layer is a pearlite/clay insulating layer. I used a ring of bricks as a dam to hold the insulating layer in place until it dried. The bricks were removed and some were used in the construction of the arch .
The top layer is a 3-4″ thermal layer of clay/sand and finally levelled with dry sand before laying the tiles.

I stacked the rocks such that they would fall “inward” if shifted, so they end up holding each other up without mortar. I did pack some cob in between some rocks that wiggled a bit to stabilize them. This is my first oven and if it was a failure I wanted a way to quickly dismantle it.

I added the wood storage “garage” in November. It is made of a large terra-cotta planter which was destined for trash day when the bottom broke off. I set it on a pile of rocks and locked it in place with cob. I used a few saltillo tiles to form flat shelves that have already come in handy on cooking days. My neighbor says its starting to look like Jabba the Hut. I’m going to help them make their own oven in a couple weeks.

My oven is in Austin, TX and we don’t get many days of rain, but when it comes, it comes in torrents. For now, I wrap it in a tarp (it’s “raincoat”) when the clouds are ominous.

I use it every other week or so. I expect to use it more in summer when I’m banned from baking bread in the kitchen and thus heating up the house. I’ve cooked the predictable loaves of bread. We do pizzas more often than I thought. One night I made a delicious but overcooked roast beef (watch the temperature!). I’ve baked cookies and apple pies in it and we roast eggplant and cherry tomatoes in the residual heat. The morning-after temperature is often over 100F. I hope to get a small “tuscan grill” custom made for it from a local blacksmith so I can do more meat directly over the coals.

Well it’s an absolute beauty Andrew. Thanks so much for sharing with us. Best wishes and happy baking.

Simon.

P.S. Here’s a few more photos.