A few months ago, we got down to building an oven, and thus, Gaia, the earth oven came into existence. Here’s how we went about it.
Deciding the Location
The location of the oven is important, as it needs sufficient ‘breathing space’ around it. Once the earth oven is put to use, it reaches high temperatures, and without enough space around, it will heat up the surroundings as well.
Designing the Oven
In the meanwhile, the oven needed to be designed. The width and height of the ‘oven door’ were to be 63% of the oven’s inner dome’s width and height, respectively. This ratio makes sure that the door dimensions are proportionate to the size of the oven itself. So the dimensions were finalised based on the space available, the ‘door’ of the oven, and the size of the pizza to be cooked inside it, of course!
Before getting down to building the oven, the base for it needed to be prepared. A suitable height for the oven was fixed and the base was assembled over it. The base for an earth oven needs to be insulated well in order to hold the heat inside, or else once the cooking begins, the heat will get sucked out from below.
We used a couple of sadarahalli stone slabs to form the base above which a layer of burnt clay bricks was placed close to one another, making sure that none of them shift once the building of the oven begins.On-site
With the base prepared, the basic dimensions of the oven were to be fixed on-site.
Everyday things that can be commonly found anywhere were used to get the radius and height of the oven on-site, as shown.
The initial stage of building the oven is a lot like building sand castles. The dome shape is achieved by the use of moulded sand, over which layers of mud mix are applied. Except in this case, due to availability issues with sand, quarry dust was used to make the mould instead.
So in order to make a strong and well-shaped mould, it was required that the quarry dust was mixed with just enough water, such that it maintains its form when demoulded from a cup.
The quarry dust mould was then built over the brick base. Starting with making a shallow cylinder at the base, the dome was then built over it, making sure the curvature was equal on all sides.
For the door of the oven, a ‘door’ with the previously finalised dimensions was cut out and placed in front of the upcoming bell-shaped mould. It was made to stand with the support of mini bricks. Once the ‘door’ was in place, the elongated entrance of the oven was built out of quarry dust as well.
Once the inner dome of the oven reached the required height, sheets of a newspaper were laid upon the surface of the mould and water was sprinkled on it.
This was done so that the quarry dust mould does not get dried up and crumble underneath once we started layering the mud mix on it.
While the mould was being covered with newspapers and water, the mud mix for the insulation shell was prepared.
The mix for this was composed of 1 part soil, 2 parts quarry dust, and just enough water for the mix to be rolled into small balls, but this ratio entirely depends on the soil being used.
The consistency should be such that you can make balls a little smaller than the size of a tennis ball and if pressure is applied to smear it across a surface, it spreads easily, too.
Layering the mix
Hence, after the mould was ready, layering of the mud mix over it was begun. The mix was made into balls and smeared carefully on the shell surface. This was done evenly on all sides in layers. The thickness of the shell varied from 7.5” at the base to 1” at the top.
Once the mud mix was applied evenly on all sides, the oven needed to be left to dry. During dry weather or summers, the sand base can be removed the next day itself. But since the oven was built during the rainy season, it required a few weeks to dry before the sand mould could be removed from the inside. This waiting period can range from 3 weeks to more than a month, depending on the humidity levels.
After the waiting period, when the outer layer of the oven had dried completely (it needs to have dried completely!) the ‘door’ was removed from its place, and the quarry dust was scooped out carefully from the inside. The sheets of newspaper that were layered over the mould get stuck in the mud and over time get burnt off as and when the oven is used.
And so, after much hard work and patience, Gaia was finally complete, and so beautifully at that!
Text & illustrations by Hariti Ganesh