On Heating a Bake Oven

Plate 1. Vol. 8, Encyclopedie ou Dictionnaire Raisonne (etc), Diderot and D' Alembert, editors, Paris 1751-1780. This monumental work is familiarly known as Diderot's Encyclopedia and is a primary source of reference for all students of the crafts. Pictured here is the shop of a pastry baker.

Excerpted from The Chronicle, Vol. II, no. 1, January 1954

The following passage is taken from Chapter 5, Article 3 of Le Parfait Boulanger (The Perfect Baker), by M. Parmentier, Paris, I778, and has been translated from the original French by Jean and Gene Sheldon of Williamsburg, Virginia.

The moment for firing the oven is determined by the seasons and the kind and quality of the bread to be baked. In summer, as the dough rises rapidly, especially when made into large loaves and of dark flour, one should start firing tile oven when one begins to twist the dough. In winter when tile dough takes much longer to ferment one fires the oven much later.

Any combustible matter can be used to heat the oven, so long as it gives a bright hot flame to heat tile oven and also leaves embers to heat the hearth. Straw, dead leaves and plant stems would not give this double effect. Wood is the only material which can be used for the purpose.

The best kind should be not too green but not too old and dry. In winter the wood can be put in the oven to dry but in summer this is unnecessary. Placing the logs at the edges for a few moments between loads is sufficient. Even this dries up the wood and reduces its burning quality by removing the sap which feeds the flame and heats the oven evenly to the right degree.

Bakers who complain that their hearths do not last should check on their habit of throwing the logs into the oven. This damages the surface of the hearth and often the dome. Overdry wood is like old wood or coal and its heat does not spread out but stays concentrated, resulting in an overheated hearth and underheated dome. Green wood is also unsatis­factory, not burning brightly nor quickly enough. Green wood should be split and stacked at the edges of the oven as soon as a load of bread has been removed. But in order to preserve the hearth and dome for a long time it is wise to leave the oven empty after the last batch is finished.

All types of wood can be used but it is to the baker's advantage to choose wood which will burn brightly and for a long time without leaving too many embers or soot. Bakers who, for economy, use driftwood or deal make a mistake. The first has lost its combustibility through exposure to the water and the second gives little heat but a lot of embers. Beech wood, on the other hand, heats much better and goes twice as far. As is well known, painted wood is dangerous in the oven as its toxic qualities can be absorbed by the fermenting dough.

To prepare the oven for the loaves it is not enough to throw the wood in anyhow, light it and let it burn quietly un­til reduced to embers. The manner in which the wood burns and the intensity of heat which it gives out depends partly on the way it is arranged in the oven and the care taken in keeping it burning, with more or less flame, and in spreading the embers, thus giving an even heat in the whole oven.

We have already given the reasons which condemn the practice of putting wood in the oven to dry – it creates a fire hazard, the loss of humidity makes the wood less combustible and cools off the oven and, finally, putting the wood in and out of the oven damages the hearth. This is why the helper in charge of firing the oven should load the wood with a shovel and slide it gently into place leaving about a foot be­tween the oven edges and the wood to facilitate the removal of embers with the ember hook. In any case, the oven is hottest at the edges and the bread would not only be overdone but dirty on the bottom.

Large logs are used for the initial firing of the oven. The amount is always determined by the interval between the completion of baking and the start of work on a new batch.

It is easy to keep the oven going when once started. It follows that the baker whose business only requires two or three oven loads, uses as much wood as the one who makes twice as much bread. Bakers who arc not very busy and arc reduced to one oven load cannot make expenses. Bakers' helpers often make the mistake of overheating the oven, either to speed up the work or because of a liking for overdone bread. They are even known among their companions for this fault and Master Bakers should go to any lengths to correct it.

Firing the oven would be the easiest of the operations connected with baking if it were possible to fix the quantity of wood by weight or number of pieces. This, however, varies with each season, each load and each kind of dough and re­quires intelligence and ingenuity on the part of the helper. One on well realize the worth of the baker's helper who un­derstands this work, who can do it economically and who takes pains to do it with care and without sparing himself. This man's bread is always well cooked and never burned.

Bakers who have learned by experience to be careful will never allow themselves to be caught unprepared when the dough is ready. It is far better for the oven to wait for the dough than for the dough to wait for the oven to be ready. One can always maintain the heat in the oven whereas one cannot readily stop or start the fermentation of the dough. It is true that this circumstance should rarely arise if one has followed the given instructions for the kneading of dough .

The oven consists of several parts and when firing it, these parts – the dome, the rear, the sides and the mouth – must be taken in to account. They are known as the "quar­ters." The first part of the oven to become heated is the dome, as the flames naturally rise. The last part is the mouth, which is continuously cooled by the outside air.

The season will in influence the moment when the oven should be fired. In w inter, for instance, logs are put in to the oven several hours after the last batch has been taken out so that they will light more easily. The wood is not lit until the kneading is finished and, in very cold weather, not until it is weighed, turned and set out to rise. In summer the wood is lit when the dilution of the sponge is begun, because often the first loaf sh aped is ready for baking while the last batch is still in the oven.

Experience soon teaches the best way to arrange the wood in the oven. First one places a rather crooked log at the rear. This will serve as a support for the others and, being crooked , w ill allow the flames to circulate freely. Two other logs are then placed on the first with ends crossed and two more on these last so that the ends will reach to both sides of the oven and be about two feet from the mouth. The stacking of a number of logs in this manner is called the "charge ."

The wood is lit by a burning brand placed at the rear of the oven facing the mouth. The highest pa rt of the leaning logs burns rapidly. The smoke which pours from the lower ends and runs up the logs feeds the flames, making a bright hot fire without soot. In other words, just the right fire. Those logs which support the others would burn and make too many embers, which would overheat the hearth if one did not spread them out with an old peel or a poker and restack as before.

It would be a mistake to wait until the flames died down before thinking of heating the mouth of the oven. The embers, if they burned completely, would overheat the hearth, while the dome would not be hot enough. The embers must be removed – pulled toward the mouth of the oven with the large ember hook and then pulled with the small hook on to the scovil and dumped into the cinder pail. Were one to put the embers at the edge of the oven, the way some bakers do, they would be lost and the bread might be burned. All that is left in the oven is a brand to light it up.

The oven is not yet ready for even baking. The flames and the embers have not heated all parts of the oven, par­ticularly the mouth, and it is most necessary to light a second fire in this spot.

This fire is made in the same manner as the first except that the logs arc split instead of being whole. They are stacked on a slant on top of a burning brand about a third of the way into the oven with their ends reaching to the left and right edges. Six or seven may be placed in this way. The assistant must build the fire far enough into the oven so that the flames will be directed toward the dome and not out of the door and up the chimney where they might set fire to the soot, causing a chimney fire and disaster. As the logs burn down they must be restacked and drawn forward toward the oven mouth. If the dough is ready and there is no time to burn kindling at the mouth of the oven to heat it evenly, it is better to forego this advantage than to miss the right moment to load the oven when the wood is burned up and all is ready. Sometimes the embers must be removed very quickly in order to load the oven.

This is the way the wood is placed to fire and heat the oven on commencing work . The method is a little different when one comes to the successive loads of bread. Instead of using whole logs they are split in two or three pieces and, instead of placing them at the rear of the oven, as with the first load, they are placed at one of the sides.

A brand is put in the last quarter about one foot from the edge. The tip of the first log is placed on the brand and a second one crossed on the first, one end at the middle of the first and the other end toward the oven mouth. A third and fourth log are placed in the same way toward the front of the oven and from six to seven logs are used. If the oven is large, one must use larger logs or more of them.

This is about the way the oven is fired after the first batch has been baked. Sometimes one must add one or sev­eral pieces of wood in the first quarter, but these dry up first and catch fire only as the rest of the fire is reduced to embers. As each oven load is finished fewer logs arc used because the oven once heated needs smaller fires. This is why the first firing is different from the succeeding ones.

If one is in a hurry to heat the oven one should split the logs and use more of them. To produce the same heat sooner the brand is lit before placing the wood so that the logs begin to catch fire as they are put into place. The oven door can be shut for awhile to retain the heat.

As the wood dries, the smaller flame can set it afire and produce a sudden blaze which spreads around the whole oven and is enough, in the case of flat-domed ovens, to give the desired temperature.

When the dough has been slow to be ready for baking and might not cook so quickly, the oven must be rapidly heated to a greater temperature to counteract this disadvantage. While one batch is baking one must split the logs and as soon as the first quarter is empty, the edges can be filled, as long as there is no more bread to be baked at the mouth of the oven.

When one is using two ovens and kneading two batches at once to be baked at the same time, the first oven should be heated right up to the mouth as one sets fire to the second. The dough must be just right so that there will be no delay in loading the second oven. It is impossible to hold back the dough once it is ready and the baker's assistant must be there to tend the second oven.

Some bakers, in particular those who bake large quan­tities of large and small loaves, have two foremen or kneaders and two helpers. Each one supervises his own work until it is in the oven assigned to him. Often one man bakes only small soft loaves while another bakes large firm loaves. In fact when the kneading and baking are done separately the bread is much better. In warm weather, no matter what ca e is taken with the kneading, the dough for the last loaves will still be in the rising troughs while the first ones are over -fermented – which gives them a disagreeable and sour taste.

On would think that an economically heated oven would use more wood in proportion to the size of the loaves, but experience proves the contrary to be true. Large loaves, even though quickly put first into the oven, take longer to cook than small ones. If the oven we e hotter the surface of the bread would cook too fast and the inside would stay damp and imperfectly cooked. It should therefore be a rule that the large loaves be baked in the first oven-load, as the heat of the oven is less at the beginning of the work than at the end and also lessens as the loading is done.

The difficulty of knowing when the oven is at the right temperature has resulted in different ways of measuring the heat, such as throwing a handful of flour into the mouth of the oven or rubbing the hearth and the dome with a stick. These methods, crude as they are, might serve as guides to those who bake at home. Bakers whose oven are larger, hot­ter and fuller would only be misled. Some feel that the temperature is right if the dome takes on a whitish tinge, but this can be deceptive due to the shape of the dome and the height of the edges.

The location and position of the oven, the quantity and kind of dough, its shape and size usually determine the quan­tity of wood to be used and the oven is deemed hot enough when the wood is burned. The oven is then kept hot by the smoldering embers and the door is shut when it reaches the right temperature or becomes too hot.

It is almost impossible to determine exactly the quantity of wood to use, which way to lire the oven, when to begin firing and how long to keep it up. Although it should be easy, it all depends on the position, size and shape of the oven, the materials used for its construction, the thickness of the brickwork and, finally, on the temperature of the bake shop, number of oven loads and kind of wood which is used. High sides and dome and an outside wall make heating more difficult – the dome does not reflect enough heat and in con­sequence more wood must be used on the hearth. A lot of heat can be lost through too large a mouth or a badly fitting door. All these things are a stumbling block for the baker's helper who fires an oven for the first time. The helper must feel his way until experience and habit teach him to know his oven far better than all the recommendations one could give him.