Sally Grainger, chef and author
In my previous post about Roman cooking I described a type of oven used to bake and roast food about 2,000 years ago. Known as a clibanus it was a sophisticated piece of cooking technology most likely used by the wealthy, and one with which I have spent many years experimenting.
These ovens were made with very course gritted clay and ranged in size from 15-50 cm in diameter, with walls of up to 10 cm high. A central hole seems to have been for regulating the temperature and could also allow cooks to keep an eye on the food baking inside. A flange allowed the fire to be placed on the top of the oven.
The sites in Italy where these ovens have been identified tend to be rather elite villa complexes where one could imagine the baking of delicate cakes and also warm bread for dinner. It is not necessarily apparent that these ovens were used by the less well off as a means of cooking simpler fair, and it is often assumed that they took their bread to be baked at large bakery complexes in towns, while we do not know what the rural poor did about baking at home. There was an assumption that they didn’t eat bread but made puls wheat porridge in a cooking pot over a wood fire.
The poem attributed to Virgil called moretum suggests that a relatively lowly market gardener baked his bread sub testu: under one of these ovens, though the status of this man is quite difficult to determine. He is considered a peasant, but he sells his produce in town and comes home with a heavy purse on occasion. Identifying these ovens is also not easy as they often come to pieces after prolonged use and recognising the shards (broken pieces) as testa (ovens) is problematic.
There is quite a detailed description of this oven in use in an agricultural manual written by Cato the Elder, in 150 BC. The recipe is for a special sacrificial cake called rather unfortunately placenta: the reason for which is another story altogether. It is a complex layered construction with sweet pasta sheets and cheese and honey bound in an outer pastry shell which might best be described as a round cheese strudel. While being constructed, the cook is advised to ‘heat the hearth and the testum where you are to cook’. Then ‘make the hearth ready beforehand and place the placenta on it, cover with a heated testum and place hot coals on top and around it’ (i).
From original drawings and reconstructed ovens the instructions on how to use it seemed quite logical, although my initial experiments were rather haphazard. I used a wood fire at first and rapidly broke the first oven I owned – we find evidence of metal versions of these ovens in Greece which could be used with a wood fire but ceramic, even very coarse material as these were, could not tolerate an open flame for long. Subsequently I used charcoal with much greater success.
Now I bake so often it has become second nature. The oven needs to be raised above the fire in order to be heated, so a trivet is used. Leaving the vessel directly on the fire caused rapid heat differential which caused cracking and sometimes put the fire that was inside the dome out.
I left the oven to heat over a charcoal fire and found that the hole acted as a chimney to draw the fire quite well. After a time it seemed better to close the hole and keep the heat in. The hearth I used was a raised platform and its position was crucial as a strong draft also helped the fire to heat. After about an hour or sometimes longer when the heat from the surface caused our spit to sizzle – a past visit to a wood-fired bakery had already told me that when the roof of these ovens is white hot that is when the baker knows it is ready to use.
At this point the hearth needs to be prepared which meant cleaning away the fire so that the cake or bread could go directly onto a tile or ceramic hearth. The fire was brushed aside to make space as big as the oven, and my freshly proved loaf or a Roman cake called a libum was placed on this hot surface with a bay leaf beneath for flavour.
The oven is put back over the cake and then the fire is piled around the sides and on top. A good bake requires good quality ‘restaurant charcoal’ (heavier and therefore long lasting) to retain plenty of latent energy. It is then possible to place fresh charcoal close to the already alight coals so that a continuous fire can be maintained. The remaining embers and smaller pieces of charcoal are pushed around the sides of the oven evenly spaced so that no area is left unheated. Doing this I was able to reach 410F (210C) on a regular basis when baking bread, so could then bake and roast very efficiently.
I can only indicate the quality of the bake by offering the following:
The crust on my sour dough was beautifully thick and crisp even when cooled; meat on the legs of a small chicken roasted for 45 minutes in a dish rather than directly on the hearth, fell to pieces; a lamb shank cooked for one and a quarter hours was similarly tender, and belly pork fell apart and had super crackling after the same amount of time.
Over the years I have come to the conclusion that the relatively small space inside the oven is such that any potential moisture both from bread and also meat is retained around the food being cooked so that a steam/roast/bake process is going on. Bakers know of course that you need steam to create a good crust and now it has become common to find modern catering ovens with added steam.
All manner of complicated techniques are used to achieve the desired moist atmosphere yet 2,000 years ago the Romans had invented the technique already.
i. C. Grocock and S Grainger, 2002 Moretum: a peasant lunch revisited. The meal: proceedings of the oxford symposium on food and cookery 2001, Prospect books Totnes, pp.95-104.
Silver service: fine dining in Roman Britain is on display at the British Museum
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