Building a Wood Fired Earth Oven - Part Two
I've named our earth oven, he's called Earl. I'm just one of 'those' people. So just in case as you're reading and I refer regularly to Earl, you know what I am going on about.
We've had the earth oven in place all Summer and it's been wonderful, some excellent pizza parties with friends and family, Earl is well and truly part of the family. I can't wait to have a bit more time to test out some wood fired recipes this Autumn, but he can only really survive the winter properly if we build him a roof which will most likely turn into Part Three of this blog...
Back to where I left off. Finally achieving the smooth even brick layer base it was time to think about and start to build the dome which is the most crucial part of the oven.
I mentioned in Part One that we followed Simon's blog for our building process, we found his instructions and details to be fantastic as he writes about his own experience, but nothing can quite prepare you for the building of the dome and the texture that you need to achieve of the sand and clay layers.
I've described the bulk of the 'ingredients' you need - around 175kg clay and 350kg of sand, now imagine mixing these together, that's a lot of hard work, but I'll come back to that in a bit.
The first task is to build a simple sand dome in the middle of your prepared base. This will act as a cast/mold for building your oven layers around.
We really wanted to have a big oven, thinking we could cook more food! This meant we made our sand dome around 80cmx80cm, similar to Simon. You have to remember you can't make it exactly the same size as your base, as the oven layers are extremely thick so they will need something to sit on as well!
The sand dome it the fun part, mixing sand with a little bit of water just to bind it together, like on a beach really. We chose again to follow Simon and made our dome around 45cm high - this took an awful lot of sand!
Once you are happy with your sand dome, it's just a case of dampening newspaper sheets slightly with water and sticking over the surface. This just helps to create a defined layer between the sand and your oven wall, so when you dig away the sand, you know when you've reached the oven wall as you'll see the paper.
With the dome ready it's time to create the first layer of the oven wall. This is back to sand and clay, using roughly a ratio of 2:1 sand to clay.
The method to mix the two materials together is known as puddling - treading the two together on a big tarpaulin. Physical and tough, the mix gets sticky, wear wellies and be prepared for the long haul. Reading Simon's blog he said be prepared for how long this takes, but really don't underestimate it. Also, make up more than you think you will need as if it starts to dry out you can refresh it with a little water and it save a lots of back ache!
With the puddling, you are looking for just the right consistency, adding enough water along the way to create a nice clay brick, but not too much to make a sloppy clay mix which will just slump down when you're trying to build with it.
I can't describe it very well and if I'm honest I'm still not sure I know exactly what it feels like, we watched a lot of YouTube videos to understand this consistency and in the end went with our gut feeling.
Once you're happy with the way your sand-clay mix feels, it's time to 'slap it' onto that sand dome and start building your first oven layer! We found the easiest way was to take a large scoop of the mix, form it together in a rough block like shape and wedge it onto the dome.
The bigger the sand dome you build, the more sand-clay mix you need and the longer it will take. Try to carry out the build on a dry day or you are just battling the elements trying to get the right consistency.
And watch out for your pets! Eddie our cat loved playing with the clay leading to some hilarious but messy moments!
With the first layer complete, you can have a rest. It needs to dry out a little now, the blog we followed recommended at least 4 hours. It was rather wet the couple of days following the build of our first layer so we left it to dry a couple of days under a tarpaulin.
It's then time to get crafty and carve out your oven entrance! A nerve wracking moment as you really want your oven to stay standing, but of course it will for now as it is still supported by that sand dome underneath.
We chose the width of the entrance based on the baking peel that my brother gave me for my birthday, that simple! We didn't make it too tall, just big enough to get your arms in to light a fire, too big an entrance and you'll lose all the heat in your oven!
So just mark out where you're going to cut away, then use a large old knife and carefully take out the entrance. Really rather satisfying.
We then went a bit off piste... I decided that we didn't need a chimney or a brick arch and that for peace of mind we were going to keep our sand dome in whilst we built the remaining 2 layers of the oven walls. I wanted to use some large rocks and pebbles that we had collected from the garden for the mouth of the oven which I think now makes it look like a cave, but I like that., it's rustic and quirky.
The second layer of oven wall is different to the first, It's a mix of clay slip, mix clay in a lot of water, then add straw/wood chips. This is an insulation layer for your oven. It was back in March/April we were building Earl and it wasn't particularly warm. A tip for all you budding earth oven builders - use tepid water for your clay slip as your hands will freeze! It's a back breaking job, again, someone mentions using a powertool to create your mix, but we stuck to hands. As you can see, it was messy (very) and our wellies still aren't the same, even after a visit to a Festival this September.
Congratulations if you've built your oven to this point! Almost there. It's just a final layer, exactly like the first. The only difference is you are going to need to make more sand-clay mix than the first time as the dome is now quite a bit wider with these oven layers.
On our third layer we ended up having to build it in sections as it got too dark to carry on with the build. Our mistake. We found that when we went back to it, the new layers just didn't want to combine as well as we wanted so ended up taking some of it off, mixing it up again and then rebuilding the third layer. Extra work for ourselves, but worth it we think as we were happy the oven wall was 'sound'.
Then you've made it, success! Your oven then needs to dry out before firing. At this point we dug out all of the sand dome. I was convinced the whole structure would come tumbling down, but it held, it was a proud moment.
We left Earl to dry for around 4 weeks at this point. The first fire was a very small fire to dry off the inner layers of the wall a bit, then after around 6 weeks we fired Earl up for the first time and cooked our first pizzas in the oven.
Yes Earl has cracked slightly, he has a very impressive crack a the front and back, but it's not all the way through. We will fill the cracks with more of the sand-clay mix and he will be as good as new.
Reading Simon's blog and the fixes he has carried out on his own oven have filled me with confidence that you can mend and patch as time goes, it really isn't the end of the world with a few cracks, only if the oven cracks all the way through the three layers of the wall.
It took us a long time to build our earth oven and it was a much more physical process than I had thought it would be, but I would say it has been incredibly rewarding and you can cook some incredible things using the oven.
Would I build one again? A few people have muttered questions of would we help build one.... No, I wouldn't build one for someone else, it's a lot of work(!) and pressure that it is a success, but I know we will be building one in the future after we leave No12, I think it's part of the family.