Clay outdoor bread oven??

[erinszoo]

I've been reading up on building our own clay bread oven outdoors and am really interested and excited about doing so. Has anyone done this yet or have experience with it?

 

[wyoDreamer]

I have the book on building an earth oven, that is the limit of my experience.
However, I think when I do it, I will be building one with a fire brick interior. We heat with wood, so a wood fired oven would be awesome. I am going to need something that I can use for pizza as well as bread, so it need to get up to 600 degrees at least.

Going to keep an eye on this thread. I too would love to hear from anyone who has a brick oven!

 

[erinszoo]

Yeah, we want to do pizza in it as well. We love that crispy crust you can only get with a good clay oven heated up really hot. I have directions on making it but was hoping I'd get some tips on what to do differently or try differently. Maybe it's just idiot proof and there's not much to worry about. I hope. Lol!

 

[erinszoo]

We got the base built for our oven today. This pic is just the start of it. I'll take pics along the way and post them. It's three blocks high and the center section is for firewood. We have a fire pit right next to it that we're rebuilding so it will be up higher than it is now. We went and priced sheet metal for the base of the oven today but couldn't afford to buy it yet. Hopefully next week we'll get it bought and then move on to forming the clay oven itself. I'm so excited I can hardly stand it!!!!

 

[erinszoo]

So this week we are testing soils that we have dug up to find the right mix of clay to sand for the cob that will be the oven itself. We don't think our soil at home is going to work as it has a lot of silt in it and very little clay. We'd probably find more clay but I'm not sure I want to dig a four foot hole in my yard just now when I know that I can get better clay soil at my parents house. Their soil is almost pure clay so we'll have to mix it with sand and form some bricks to see what mix we need.

Just for tutorial purposes ... you mix your clay soil with sand in percentages like 10%, 20%, etc until your mix will no longer stay together. At each percentage you form a brick with it, mark the percentage on it, and leave it in the sun to dry. Once the bricks are dry you start with the highest percentage sand brick and drop it from shoulder height working down in percentage. The first brick that doesn't break when you drop it is the mix to use.

For an oven your first mix will just be clay soil, sand, and water. This will be the first layer of the oven. Once it is dry enough to scratch up the outer surface, you then mix clay soil, sand, straw, and water for the other layers. This makes the inner layer of the oven hold heat better while lightening the total weight of the oven. I've seen them built with an entire layer of straw put over the second or third layer of clay and then that layer of straw clayed over as well to give an insulation layer, but I don't know how well it really works. We'll see what we do when we get there I guess.

 

[wyoDreamer]

I never heard of that method to determine your clay mix. Pretty interesting. I know we don't have enough clay around here to build the inner oven with, so I will have to buy all of my materials.

Are you forming your dome with sand and packing the clay onto that for teh shaping?

 

[erinszoo]

Yes, we're using sand to form the shape. I've read that almost all soil has some clay in it but I tested my own yard and it only had a tiny layer of clay compared to sand and silt ... not enough to make it worthwhile to use. So today we went down to the river near our town and got a test bucket of soil. We had to dig down under the sand a little bit until we hit hard pack stuff but it didn't take very long to do. We maybe spent 15 minutes at it and that included me climbing stairs with my sprained ankle. Here's our pics in no particular order.

Mixing sand with the clay soil to form bricks



Bucket full of test soil from the river


More mixing


Test bricks with no sand, 10% sand, and 40 - 50% sand added


Test bricks with 75 -80%, 150%, and 300% sand added. I didn't think we needed to do that much percentage but my husband read somewhere that the mix can go that high if you have really pure clay so I humored him. He was having fun playing in the mud I think.


And here's all the test bricks lined up to dry outside (with a few flies just for good measure)


Now we wait for them to dry a couple of days before we can start dropping them. I think we'll end up using the 40 - 50% mix for the inner layer but my husband thinks it will be the 75 - 80% mix. Since he was the one mixing it and feeling it, he may be right. Then the outer layers we'll add straw to as well and I have a few ideas for decorating the whole thing to add a little whimsy to the project.

 

[DennisK]

Sorry about that, but I seem to be having problems with my browser.

Take care not to let fire come in contact with those cinder blocks as they tend to crumble when they are subject to intense heat. I built a yard incinerator using cinder blocks and the whole thing crumbled in a short time. At that time, I was making bricks from cement and clay; so I confiscated some of them to be used for my new incinerator. It has been more than a year, now, and there is no deterioration. Good luck with your project. I hope to follow your example soon.

 

[erinszoo]

Thanks DennisK, I'll figure out some way to isolate the concrete blocks from the oven platform then. Maybe I'll set the steel plate in a bed of cob to dissipate more of the heat before it comes in contact with the concrete bricks. What percentage mix of cement and clay did you use for your bricks? The soil we found is almost 100% clay so any additives we put in to help it remain stable and last longer the better as far as I'm concerned. I don't want to go to all this work to have to take it all apart again and redo it next year. That would be depressing.

 

[Ithildyn]

I have a book, and want to build one one day - I love making pizza and baking bread. You're the first person I've come across who is building one. Looking forward to your reports!