Sally Grainger, chef and author
In previous posts I introduced the different types of ancient portable ovens which are generally called either clibanus or testum. The former term is the more fashionable Latinised Greek word while testum represents the Italian tradition for these ovens.
Currently on display in the Life and death in Pompeii and Herculaneum exhibition at the British Museum, there is a unique double casserole/oven with a base and domed top. In this post I will discuss the results of preliminary experiments I’ve been undertaking with a replica of this so-called clibanus oven.
This oven appears to be designed to allow fire to be above and below the food being cooked. This concept is found in recipes in the Roman cookery book known as Apicius for a dish called a patina which is a thick frittata cooked in a vessel of the same name. The instructions are as follows: ‘grease a clean dish and put it in the hot embers, pour the mixture in, allow the embers to be above and below (the dish).’
Readers of Apicius are not told precisely how this may happen but we can imagine the dish must have had a lid for the fire to be on top of the food. There are many North African-ware lidded casseroles that would suit this technique, with a small base that sat in the embers on the hearth and curved walls to allow embers to be pushed beneath the vessel, from the Roman period. The lids had a slightly curved outer rim which would have kept the embers away from the food when the lid was removed: a design feature similar to the flanged single oven I described in my second post. I have experimented with this technique too using a vessel created by Chris Lydamore and found it very successful.
Line illustrations taken from my edition of the Latin text of Apicius shown here demonstrate just how versatile this kind of equipment can be. The single testum/clibanus can function with a completely separate smaller dish inside and what seems to have happened with this new vessel is that the roasting dish becomes integrated as a double unit.
In Apicius the foods described as being cooked in a clibanus like this one are generally rather small and defined as roasting or pot roasting. Recipes include a dry roasted, stuffed dormouse (Ap. 8.9); stuffed kidneys roasted in oil and fish sauce (Ap. 7.8); a neck joint also cooked in a layer of sauce (Ap. 7.5.5) and a boned stuffed kid (Ap. 8.6.6).
Initially I tried a favourite dish known as ‘Parthian chicken’; technically a ‘pot roast’ (Apicius 6.8.3). Chicken pieces are cooked in a ceramic dish in a mixture of wine and fish sauce with caraway, lovage, asafoetida and pepper. We are simply told to cook it without any indication as to whether it’s on a heat source or in one. I found straight away that I had to provide twice the space and twice the fire size to heat both pieces of this new vessel in the same way as I would for the single oven.
This implies a more sophisticated kitchen with a greater volume of fire at the disposal of the cook. The recipe does not suggest you fry the meat first but I tried by adding oil and heating the bottom dish and found that this was very possible. When the vessel was put together, despite the flat base which prevents the embers going right underneath it, the fire is still able to be placed under and on top of the wide flange and as the fire must also be placed on the lid, we can assume that it’s possible to have three levels of fire around the dish with the potential to create an intense level of heat.
As the cooking progressed I was able to check inside and found that the sauce was simmering consistently all around the meat and generating plenty of steam which, in a similar way to a traditional tagine, gathers in the dome and falls back into the dish, preventing the meat from drying out. The chicken legs cooked in 45 minutes to a degree whereby the leg bone came out of the meat when pulled which was quite impressive!
In order to test the vessel for its dry baking efficiency I heated both pieces as before but left the base vessel for longer. It was clear from other cooking experiments I had conducted with Roman ceramic vessels over charcoal that when the fabric stays dry over intense radiant heat it is much more fragile and susceptible to cracking. Which, sadly, happened. The base vessel cracked quite quickly but only from one side and the subsequent bake was completed. I did not get that wonderful perky ‘lift’ one expects of a bake stone but as the dome is quite shallow it does not seem to me likely that the vessel was used to bake risen loaves of bread.
Flatter bread is generally baked with a drop scone technique on an open bake stone and the lid is unnecessary. In my experiments the colour and crust came out quite good and the crumb light and airy. I need to bake more bread in the vessel and also attempt to bake other cakes such as the libum ‘Roman cheese cake’ in order to determine whether baking was truly possible in these vessels.
First thoughts after cooking with the vessel three times now? It is super-efficient as a general purpose casserole for what we would call ‘pot roasting’: roasting in small amounts of liquid. It has proved less effective as a dry oven whether it be for meat or bread and cakes.
The naming of things and in fact the concept of defining the purpose of an artefact from the past is very problematic as we almost always use modern concepts to define ancient things and this can interfere with our interpretation. So for instance today we bake in an oven, but stew or braise in a casserole. A casserole generally functions today with wet food or sauces and either inside an oven with a radiant heat source or above a heat source on a hob. Rarely does it function as an oven in itself as the ancient casseroles seem to do when the fire is in direct contact with the vessel.
I think we can be fairly certain that the vessel in the exhibition is a form of clibanus but that term seems to be rather more complex than simply a ‘portable oven’. It might be better to define this ancient clibanus not as an oven at all but as a ‘tagine’.
Drawings by Dan Shadrake
Silver service: fine dining in Roman Britain is on display at the British Museum
until 4 August 2013.
The Asahi Shimbun Displays