This weekend we set about making an oven for bread and pizzas, using mud. We have a brick barbecue edifice on the patio, and so we used that as a platform.
First we bought and laid 21 red bricks on a 1/2″ layer of sand, making sure to get them even and with small gaps. We could have just used the existing brick oven base, but we wanted something very flat, which it wasn’t. There’s nothing worse than catching your peel on an uneven surface when trying to extract a pizza.
Next we marked out on the bricks where the wall of the adobe oven would go: both the inside and the outside edges, using a sharpie. We had bought five 50lbs bags of medium sand, most for the oven wall mix, but some for the oven mould – basically a mound of wet sand like a sandcastle.
The mound needed to be 16″ high, so we first cut a stick to that length and positioned it in a small mound of sand at the centre of the oven bricks.
Then we started to build a sandcastle around the stick, trying to keep the sides of the sandcastle as vertical as possible, and making sure that the sides followed our outline of the inside adobe walls we had marked on the bricks.
Once we had our sandcastle made (in the shape of a dome, reaching the top of the stick), it was time to go digging in the garden for subsoil – the stuff under the topsoil that contains the most clay. We dug about a 3′ deep hole and then extracted a wheelbarrow full of soil.
The clay soil needed to be mixed in one part soil to two parts medium sand. To mix it, we made a ring of four buckets of sand, and put two buckets of the soil in the centre. Then we set about sprinkling it with water and treading it all in to mix it. In fact we found that we had too much sand, and ended up using six buckets of soil to the four buckets of sand.
We checked that the mixing was good when a golf ball sized piece of the mixture, when squeezed tight, and then dropped from shoulder height, didn’t crumble when hitting the ground, but rather just squashed to an oblate spheroid.
At this point we were ready to apply the mud to the sandcastle former. First we placed sheets of damp kitchen paper over the former – this is so that, when we come to remove the sand, after the mud had been applied and set, we could tell when we were at the edge.