The Fresh Loaf

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earth oven

boule's picture
boule

I am about halfway with my earth oven being built from Kiko Denzer's book. I also have the Alan Scott book, but decided on an earth oven as the reuse of material appeals to me. Many friends are highly sceptical about building with clay.

It took quite a while to scrounge for the material as I wanted to buy as little as possible. The rocks for the foundation I found in the garden and then I filled it with building rubble from a nearby restaurant that burnt down (hope that does not predict disaster with the oven). The gravel I found on an open lot where someone dumped it. The wine bottles are all from our own consumption over quite a while :).

Carting rubble and live load

Every little bit of compaction helps

The hearth should be on a nice level once finished as the oven is being built on a terrace.

Chief designer

First insulation

The sawdust I had to buy in the end and it cost about $4. The bag it came in was almost as expensive.

I realised that the front part needed some work and then happened upon some nice flat rocks. The next photo shows an improvement where the tongue will be.

Heat retaining slab under hearth

I am now ready to bring the level up with a sawdust and clay mix around the slab. That will be followed with a thin layer of sand bedding for the fire bricks.

I finished the first layer all by myself and that was not a good idea. Some friends would have made it easier, but I was in a hurry and nobody was available on that sunny day. After two weeks of sitting underneath the sheet in pouring rain, I started a small fire. As you can see the clay was still quite moist. I wanted to see if the fire would burn before finishing with an insulation layer and the rest.

Finished first layer

The fire burnt very nicely and started to dry out the clay.

I let it burn for quite a while. The next day the oven looked dry, except for the bottom part where it was still moist. So I started another fire and made it nice and big. Oh, the horror: it cracked! I suppose that is what you get for being impatient.

The CRACK

The crack then spread over the dome. I am hoping that it is not too serious, since it does not seem to have cracked right through. That means I cannot see through the cracks.

I am planning to patch it up with some sloppy clay, but I would appreciate any tips here.

BTW, we cooked a chicken in the oven four hours after the fire died down. It went in for 2 1/2 hours and was beautifully soft. Because it was so late in the process, I had to brown the chicken in the electric oven.

Now it is August and the process took much longer than anticipated. At least I think it is finished and I cannot wait for it to dry out.

Arch

So I added a chimney and a brick arch. If I had to do it again, I am sure the arch would be better.

Cladding

Some time later a friend helped me to add the insulation layer of clay slip and wood shavings. Here it is almost finished.

Jubba the Hut

The past weekend I finished the oven. Guess who did not read the book again and forgot to chop the straw. Now I have a hairy oven. Unfortunately we are away this weekend, so I cannot try it out. Hopefully there is no rain the weekend after that, so I can fire it up proper and see what happens. Will post some pictures if it works out.

shimpiphany's picture
shimpiphany

i finished the earth oven to the insulation layer a week ago, and had the first "dry firing" this weekend.

i've fired it twice to try and dry the insulation layer and track the fuel and heat usage, although i won't get accurate estimates on this until i'm sure the entire oven is dry, at least a few weeks from now.

on saturday, i fired it and made pizza. because of some bad scheduling on my part, i was unable to have any bread ready to bake in it, although we did use the tail end of the heat for potatoes and roasted garlic.

i'll fire it and bake bread this week, hopefully tuesday.

here are some photos:

here i am getting the fire started and losing some eyebrows:

here is the fire once it got going. after the fire got some momentum, it became a lot easier to keep it alive - wood placed in the oven would instantly burst into flames instead of needing to be coaxed. at this point, my infrared thermometer (which reads up to about 1000 degrees F) was off the charts:

the tongue of smoke. smoke means an inefficient fire. efficient firing and use of fuel is a very challenging part of this oven:

another view of the fire:

the infrared thermometer. its max is around 1000 degrees:

the themometer. a very fun tool:

here i am rolling out the pizza. i like the flat crust, so i use a rolling pin (blasphemy, i know):


the pizzas. porcini, homemade sausage and onion; and goat cheese and braised leeks. the sauce and crust are adapted from reinhart's american pie:

i'm experimenting with sizes to see how i can best maximize the floor space: 

cooking:

my father-in-law wielding the oven door, several 4x4's joined by countersinked (countersunk?) screws, joined to a 1x12 sleeve and mounted with two concrete float replacement handles:

with the door in place:

the finished product:

more to follow once i finally get some bread in there...

 

 

shimpiphany's picture
shimpiphany

with the help of my dad and sister, i finished the insulation layer on the oven. the only thing left to do now is a plaster layer - which won't affect the performance. that means baking can begin as soon as this layer is dry enough.

before we applied the final layer, though, i ran a cook of four pizzas.

we gobbled the pizzas after they came out, so this is the only "cooking" photo.  i used parchment paper because i don't have all the oven tools yet, and couldn't clean out the ash.  my sister is fabricating most of them for me (she is an artist and metalsmith), so i should have all i need soon, well under my $200 budget:

a few days later we put on the insulation layer, a 5 inch thick layer of mud, sand and straw.

here we are mixing:

here's the final layer. we were all covered in mud with no one to take pics of the process, so i only have a photo of the end result:

i'm going to build the door this week, and with the weather as hot as it has been, it should be ready to bake by friday.

wish me luck, and thanks for all your support.

breadnerd's picture
breadnerd

Continued from an earlier entry....

 

We let the first layer dry a few days, and some fairly big cracks started to form. I decided to pull out the sand to give the oven more room to shrink as needed, and to help it dry out faster. I cut a smaller door than the final size, you can see the final door scored into the surface:

http://farm2.static.flickr.com/1239/1443314684_81e061fa2b.jpg?v=0

 

We ended up letting it dry for a couple of weeks due to rainy weather and other activities. It was covered with a tarp and opened up when the weather permitted to dry out. Next came the second layer. The first layer is just sand and clay—the second is cob: sand and clay mixed with straw.

http://farm2.static.flickr.com/1368/1443313710_f479fba985.jpg?v=0

 

The second layer goes on much faster, but as it's 6 inches thick you use up a lot more material as you go. We made LOTS of batches of this.

http://farm2.static.flickr.com/1260/1442449505_b5cda095e2.jpg?v=0

 

Almost there:

http://farm2.static.flickr.com/1182/1442450317_7efc87c836.jpg?v=0

 

Refining the doorway:

http://farm2.static.flickr.com/1208/1443313758_b3154e54b5.jpg?v=0

 

Our door, made from glued-up 4 x 4s, and shaped with a sawzall. Did I mention I have a very handy assistant?

http://farm2.static.flickr.com/1244/1442450793_11879b0dcc.jpg?v=0

 

We lit some small fires at this point to aid in drying, and after a couple of weeks started using it. The first few attempts had a big learning curve, and I think I joined the fresh loaf soon after that and documented my later bakes.

 

The oven was built in May and June, and we left it without a final protective plaster because we were undecided on what to do. We would cover it with a tarp when not in use. Finally, we decided just to make a roof over it, so there is no final plaster layer. It made it through a winter and another summer without much damage. Here’s the final oven with it’s roof:

http://farm2.static.flickr.com/1435/1443313790_6629aee699.jpg?v=0


Many thanks to Kiko Denzer for a great book--its a wonderful way to give wood-fired hearth baking a try without a huge amount of investment (well, if you don't count your time!). I also have the Bread Builders book which I found useful as well, I just didn't have the right location and finances for a masonry oven, and I think after a few years using the "mud hut" I will know better my needs and desires for any future ovens.

 

breadnerd's picture
breadnerd

I finally got up the gumption to move my construction photos over to my flickr account. Here they are in the entirety, I tried to make the titles fairly self-explanatory:

http://www.flickr.com/gp/7541655@N03/aX31kR

 

Here's a condensed version with some commentary:

First off is the foundation. Our frost line in in theory 48 inches, so we dug down quite a bit. We hit a VERY large rock, which made us decide the hole was big enough, and which we figured would act as a foundation in itself.

http://farm2.static.flickr.com/1012/1443314626_31ba338401.jpg?v=0

 

Next, we filled the hole with gravel and started building a foundation from rather unattractive landscaping bricks we already had from another project. We added a layer of lava rock for insulation, Kiko’s new edition has a lot of better ideas for this, but this has worked okay for us.

http://farm2.static.flickr.com/1410/1443314822_1f6502d8de.jpg?v=0

 

Next sand is added, packed, and leveled, and we laid the oven floor bricks. A string was used to draw a circle as large as we could fit on the floor, as our guide for the sand mold form.

http://farm2.static.flickr.com/1367/1442450837_2025385af8.jpg?v=0

 

The sand form took a lot longer than I thought it would, but it turned out nice.

http://farm2.static.flickr.com/1110/1443315018_c94673ba68.jpg?v=0

 

Because of this, we didn’t get very far with our first layer before dark, but you can see the width of the walls, and how compact it was. We were probably overly persnickety with this first layer:

http://farm2.static.flickr.com/1319/1442451223_365f1a3e72.jpg?v=0

 

We covered it in plastic, and resumed the next day.

http://farm2.static.flickr.com/1331/1442450183_71089d3c3f.jpg?v=0

 

Final first layer, wacked with a 2 x 4 and scored for the next layer to stick:

http://farm2.static.flickr.com/1162/1442450281_d233d47f01.jpg?v=0

 

 

more to come....

 

 

Oldcampcook's picture
Oldcampcook

I am going to have to stop reading this blog during the day time while I am at work.  It is very difficult to maintain a proper decorum while I am rolling on the floor laughing!

Old Camp Cook 

pumpkinpapa's picture

Earth ovens and breads

April 24, 2007 - 2:58pm -- pumpkinpapa
Forums: 

I found this on another list and thought there may be some here who would be interested to know that Kiko Denzer and Hannah Field are on tour promoting their simple designs for earth oven building and naturally leavened breads. The schedule is as follows:

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