A Treatise on Baking

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The Scientific Manufacture of Bread

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Chapter X

THE SCIENTIFIC MANUFACTURE OF BREAD

THE SCIENTIFIC MANUFACTURE OF BREAD

I. RAW MATERIALS

The four primary materials without which bread would be an impossibility are flour, water, salt and yeast. However, in order to produce bread of the high quality established today, other materials such as malt extract, sugar, milk, shortening and often mineral salts are necessary.

In order that a baker may operate his business efficiently and secure the highest quality baked goods at the lowest manufacturing cost,—consistent with the maintenance of quality it is necessary for him to exercise considerable care in the purchase of the raw materials and in storing and handling the same. To do this with intelligence requires a pretty complete understanding of the nature of each ingredient and the part which it plays in the production of bread and other baked goods.

Therefore, separate chapters are included herein which deal with the basic materials used in the making of bread, — explaining in detail the manufacture, properties, storage and handling of each. In view of the importance of knowing these ingredients thoroughly so as to handle them to the best advantage, it is advisable that the baker become thoroughly familiar with these chapters.

In striving for the greatest production efficiency it is sheer folly to think that this result can be secured by the use of inferior materials or by cutting down on the worthwhile ingredients in the dough batch essential to good bread. The result of doing this is a lower yield of inferior bread and represents not only false economy but actually a very dangerous form of extravagance. Inferior materials although correctly handled cannot produce the best quality bread.

II. HANDLING OF DOUGHS, USE OF MACHINERY AND INSTRUMENTS OF PRECISION

In addition to the formula and materials used, every step in the handling of dough from the mixing of the ingredients up to the cooling and wrapping of the baked loaf as well as the proper control of temperature and humidity have an important influence on the quality and yield of bread secured. The use of suitable bakery machinery not only saves time and labor and lessens dough losses but also assists materially in increasing the yield and improving the quality of bakery products. The different concerns making such machinery have conscientiously studied the needs of both large and small bakeries and today there are available many varieties of machinery such as mixers, dividers, rounders, moulders, etc., designed to meet the peculiar needs of practically every baker. Naturally a baker should give considerable thought to the selection and purchase of this machinery so that he may secure the machines which are best adapted to his particular requirements. Adequate information and advice in this connection can be very easily secured from the machinery manufacturers.

There is also on the market, air conditioning equipment which automatically controls and regulates the temperature and humidity of the bake-shop thus insuring the optimum conditions for the fermentation, conditioning and handling of doughs.

While many bakeries do not have such equipment,—it is absolutely advisable to have some arrangement whereby the desired temperature and humidity may be secured. In this connection the use of dough thermometers, room thermometers and instruments for indicating the degree of humidity are indispensable in the efficient production of quality bread. Because of the importance of controlling the temperature and humidity in bakeries, this general subject has been taken up in detail in Chapter XII.

By the installation and careful use of adequate scales and by keeping accurate records at all times,—there should be no unaccountable losses or incorrect use of materials.

Good materials and a good formula will not produce good bread unless properly handled. Therefore, it is especially important to pay considerable attention to each step in the manufacture of bread. These steps are discussed briefly and separately in the following paragraphs:

III. BLENDING AND SIFTING OF FLOUR

As described more fully in the Chapter on Flour the millers of today in general blend their wheats prior to milling in order to produce a final flour which will be ideal for bread making.

However, many bakers still find it desirable to blend together certain flours in order to meet their own specific conditions and requirements.

For instance, one type of flour may possess certain definite desirable baking characteristics as reflected in the finished loaf. Another type of flour may possess other desirable characteristics. In order to secure the advantages of the desirable properties of both of these flours, the baker may blend them. However, if satisfactory results are to be secured the characteristics of the flour in question should be very carefully studied and understood and then intelligently blended in the proper proportions.

The various types of flour blending equipment now on the market are of great assistance in securing a perfectly uniform blending of flours.

Before going into the mixing machines all flours should be carefully sifted.

Blending and sifting aerates the flour thereby improving its baking quality.

IV. WEIGHING INGREDIENTS

All of the ingredients to go into the dough batch should first be carefully weighed out. No baker can afford to guess about the amount of ingredients used in the dough batch. Every bakery,—large or small, — should be equipped with suitable scales so that the amount of each material used can be accurately measured. From time to time these scales should be checked up to make sure that they read correctly. Automatic scaling devices for flour and water are of great value provided the size of the shop warrants their installation.

V. RECORDING OF TEMPERATURE AND ADJUSTMENT OF WATER TEMPERATURE

Before mixing the dough batch ingredients together,—the temperature of the flour and room should be noted and the temperature of the water should be so regulated that the dough will have the desired temperature out of the mixer. The method of calculating the necessary temperature of the water will be explained in detail in Chapter XII.

VI. MIXING

A. THREE PURPOSES OF DOUGH MIXING

(a) To bring about an intimate and uniform mixture of the necessary ingredients so as to properly form the smooth glutenous mass called dough.

(b) To make possible the most complete wetting of the starch and to insure the most complete hydration of the gluten as well as to develop it mechanically thus promoting its extensibility and pliability which is later perfected by yeast action.

(c) To completely and uniformly distribute the yeast cells throughout the dough mass, bringing them into intimate contact with the rest of the dough from which the yeast secures its nutrition, thereby supporting its activity and enabling it to perform its fundamental function of dough fermentation and conditioning to the best advantage.

B. TWO PRINCIPAL METHODS OF DOUGH MIXING

There are two standard methods of bread-making used in general commercial practice, although there are of course, variations in each method which may be employed.

1. Straight Dough Method

A straight dough is one in which all the necessary ingredients are mixed in one operation.

2. Sponge Dough Method

According to this method which is often called the sponge and dough method, a portion of the flour (usually 40 to 60% of the total amount), water, yeast and sometimes sugary agents, shortening and Arkady, are first mixed forming a dough called the “sponge” which is permitted to rise and mature to the desired point. The sponge is then put back in the mixer and mixed together with the so-called doughing ingredients which represents the remainder of the water, flour, sugary agents, salt, milk and shortening and yeast (if total amount has not all been incorporated in the sponge). It is necessary to “break up” the sponge completely in the added water before adding flour and other ingredients in the doughing stage. The sponge and dough are then thoroughly mixed until the final dough is smooth and homogeneous. It is then allowed to rise, and in some cases is turned or folded, allowed to rest for a few minutes, and sent to the divider. If Arkady is used in the sponge, it should be set 2 or 3 degrees cooler and the final mixed sponge and dough, only allowed to rest about 10 to 15 minutes before being sent to the divider. If a blend of flour is being used, it is advantageous to use the flour of the greater gluten strength in the sponge.

C. ORDER OF MIXING INGREDIENTS

The yeast to be used is broken up in small pieces and thoroughly stirred into a small portion of the water until a uniform mixture of so-called yeast solution is secured. In mixing yeast into a portion of the water as described above, care must be taken not to “shock” the yeast by mixing it with either very warm or very cold water. For this purpose the temperature of ordinary tap water is usually quite satisfactory. Incidentally neither the salt, Arkady nor malt extract should be mixed together with the yeast prior to mixing into the dough batch.

If powdered milk is used it should also first be dissolved in another portion of the water in a separate container in the manner described in Chapter IX, pertaining to “Milk,” and then placed in the mixing machine.

The salt, sugar, malt extract and Arkady and milk solution should be thoroughly dissolved and mixed together in the remainder of the water in the dough mixer by a few turns of the mixing blades or arms. Then draw flour into mixer and proceed to mix. When the flour is abou£ half drawn in, add the yeast solution. Add the remainder of flour and continue mixing. Then after several minutes mixing, add the shortening. Mixing is then continued until thoroughly completed.

D. UNDER MIXING AND OVER MIXING

It is very advisable to see that the dough is mixed to the proper extent, but not over-mixed.

If mixing is insufficient,—optimum starch wetting, gluten development and hydration and in general a smooth uniform dough will not result. Therefore, in a dough which has not been sufficiently mixed, the fermentation and conditioning of the dough will be irregular and the finished loaves will not be uniform throughout. If mixing is excessive the desirable physical properties of the gluten are injured resulting in a weak sticky dough. Such a condition will be reflected in the finished loaf by creating inferior grain, texture and volume.

E. CONDITIONS ON WHICH PROPER TIME AND SPEED OF MIXING DEPENDS

The best mixing time and speed to be employed varies with the type of mixer and agitator employed, the type of dough being made, the strength of flour, etc. In each case this can be determined locally.

There are many different types of dough mixing machines available. There are high speed, medium speed, and low speed mixers as well as mixers having a variable speed. The resulting effect of the mixing process on the dough depends not only on the actual speed at which the mixing arms rotate (Revolutions per minute) but also upon the arrangement of the agitator arms, shape and construction of the mixing bowl, etc. Naturally with an increase in the mixing speed of any given mixer, there is a corresponding decrease in the time of mixing required.

In the sponge and dough method, neither the sponge nor the sponge and dough are mixed as long as a straight dough. Inasmuch as by this method, there are actually two mixing operations involved, a shorter period for each is obviously necessary.

The mechanical mixing of the dough is very important, and has a decided effect on the amount of water which can be carried by the dough, the development of the gluten,—and the quality and yield of bread secured.

The shape of dough mixing bowl and agitation system of modern dough mixers are designed to give the best results possible from the standpoint of dough mixing.

F. DOUGH TEMPERATURE

The temperature of the dough should be recorded directly after mixing is completed.

As explained in Chapter XI ordinary straight doughs should come out of the mixer at a temperature of 76 degrees to 79 degrees F. and mature at about 80 degrees F. Sponges should be set at about 74 degrees to 78 degrees F. In shops where there is no adequate temperature control, —the lower temperatures specified should be maintained. In shops having such control, the higher temperature may be used successfully.

The temperature of doughs directly after mixing can be regulated by the temperature of the water used or by the use of a certain calculated amount of ice. The method of calculation involved is explained in Chapter XII. Other means of cooling the dough are by the use of cooling jackets on the mixer or by the introduction of chilled air into the dough during mixing.

The temperature at which the dough matures naturally is governed by the temperature of the dough at which the dough is set, the time of fermentation and the temperature of the dough room. This subject is discussed in greater detail in Chapters XI and XII.

VII. FERMENTATION AND CONDITIONING OF DOUGH IN TROUGH

A. TROUGH SPACE REQUIRED

After the dough is completely mixed, it should be carefully placed in a clean dough trough which has been lightly greased and the sides of the dough should be pulled over so that the top is smooth. If the standard regulation size trough is employed, 2 feet of trough length should be used for a straight dough containing 100 pounds of flour. Accordingly a barrel mix would require 4 feet of trough length. In the case of sponge doughs twice as much trough length should be allowed, because the sponge is permitted to rise to a greater extent than a straight dough. Thus the sponge containing 50 pounds of flour would require 2 feet of length. This same amount of trough space, however, will usually be sufficient for the sponge and dough when mixed together. If the troughs on hand are longer than necessary, the dough can be confined to the required space by means of space boards. If the trough space is too small the dough on rising will over-flow. If too much trough space is allowed the dough will spread out instead of rising properly.

If the dough room is not equipped with a humidifier so as to maintain the proper amount of moisture in the air, the dough troughs should be covered with clean canvas sheets thus preventing excessive evaporation and crusting of the doughs in the trough. The control of temperature and humidity in the dough room is extremely important and is treated as a separate subject in Chapter XII.

B. FERMENTATION PERIOD

Fermentation and conditioning of the dough actually starts as soon as the dough is mixed and continues until the action of the yeast is killed by the heat of the oven. However, the term “fermentation period” as generally used refers merely to the time which has elapsed from the time the dough is mixed until it goes to the bench or divider,—or in other words, the period of time during which the dough is in the trough. In cases where bread is made by the Sponge and Dough process, the sponge time is the period during which the sponge remains in the trough. The total fermentation period is the sum of the sponge time and the time during which the sponge and dough after being mixed together,—remain in the trough before being sent to the divider or bench.

C. TURNING AND FOLDING OF THE DOUGH

1. Turning and Folding of Dough Explained

The fermentation and conditioning of the dough in the trough should be so governed and controlled that when the dough is sent to the divider, it will be in the best physical condition for dividing. In other words, the fermentation period of any dough must be so gauged that by the time the dough has gone through the make-up process and proof it will have

acquired its proper age or maturity so as to produce the best quality bread. Naturally this is different for different doughs and also varies with the shop conditions maintained. Inasmuch as the proper ripening or maturity of the dough is a very essential factor in the production of good bread, this point is discussed more fully in the following chapter.

In order to obtain the proper physical condition of the dough for dividing it has been the custom in the past to “punch” doughs made by the straight dough method two or more times.

However, with the present high grade of bleached flour available it has been demonstrated that such doughs should not be actually punched but rather turned or folded over by pulling the sides and ends of the dough well into the center. Actual punching of such doughs tends to make the dough bucky and hard to handle,—while the careful turning or folding of dough produces the best results. However, the word “punch” is still frequently used to refer to the actual turning or folding over of the doughs.

2.  Purposes Accomplished by Folding and Turning Dough in the Trough

(a) Makes the dough more uniform and equalizes the temperature throughout, and brings new food for yeast back into intimate contact with each yeast cell.

(b) Expels a large amount of carbon dioxide which has a retarding effect on yeast activity and brings air into the dough thus stimulating renewed activity of the yeast, hastening the ripening of the dough.

(c) Mechanically assists in developing the gluten by stretching, thus assisting in creating the desired extensibility.

3.  Time at Which Straight Dough Should be Turned and Folded

In general a straight dough is allowed to rise in the trough until light, that is, until it will just recede when the lingers are pushed down about four inches, and quickly withdrawn. The dough is then cut or pulled over for the first time. The final maturity of the dough depends largely on the first turn so that it is very important that this be gauged very carefully. The subsequent turns if any, depend on the type of dough and character of bread desired. Doughs containing Arkady require less time on the first rise. This depends on the amount being used and strength of the flour. Within certain limits, a dough can be kept from ageing by successive folding or turning.

In modern bakery practice it has been found that the greatest production efficiency and the best quality of bread is secured from the adoption of shorter time straight doughs maintaining cool dough temperatures with liberal amounts of salt and yeast in the dough. In line with this progress, the number of times of turning (or punching) the dough has been reduced and at the present time, excellent bread is made from “one turn” doughs, such as are shown in part II of this book.

D. HANDLING OF SPONGE DOUGHS

In general an average short time “sponge” for pan bread is allowed to rise until it starts to recede in the trough. It is then mixed in with the “dough” and allowed to rise until light enough to recede after the hand is inserted and quickly withdrawn. In some cases the total dough is then cut over and allowed to rise for a short period of time, depending on the size and character of loaf desired. It is then ready to be divided and scaled. For water rolls, Vienna bread and for bread where exceptionally large expansion is required, the sponge is given more time to acquire additional age.

There are various deviations from the above method of handling sponges depending on the type employed. In general, short time straight doughs will be found preferable to doughs made by the sponge method but in those localities where the sponge type of loaf is desired,—the adoption of a short time sponge will prove much more advantageous than the old and practically obsolete long sponge process. A recent improvement in the sponge method of bread making is the Arkady Sponge which is described in Part Two of this book. After an Arkady Sponge is mixed with the doughing ingredients, only a few minutes rest is required before sending to the divider.

VIII. DIVIDING AND SCALING

When the dough has been properly matured in the trough,—it is ready to go to the bench or to the dividing machine. The large mass of dough is then cut either by hand or machine into pieces,—each of which when baked will give a loaf of the desired weight. Each of the individual pieces of dough should be carefully scaled so as to insure proper weight of the finished loaf and also to avoid any unnecessary loss through over-weight. In case a dividing machine is used it should be carefully adjusted so as to produce individual pieces of dough of the proper weight. A constant check up on the weight of these pieces of divided dough also should be made by frequently scaling the pieces as they are delivered from the divider. A dividing machine naturally saves time and labor and is more accurate than dividing by hand.

By experience, the baker should always know just what weight of dough is required to give him a final loaf of the desired weight. Under normal conditions for white pan bread, one pound of bread will be produced from 17 1/2 to 18 ounces of dough. Every baker should become thoroughly familiar with the bread weight and labelling laws of his particular state and be guided thereby in controlling his scaling weights so that the weights of his loaves will be strictly in accordance with the requirements in question.

There are many types of excellent dividing machines on the market. A divider cutting off one piece of dough at a time is called one pocket divider. There are also dividers having two, three and four pockets designed to conform to the size of shop in question. Care should be taken to set the divider accurately and in such a manner that the dough will receive as little “punishment” as possible as it passes through.

IX. ROUNDING OR BALLING UP

In dividing the large mass of dough either by hand or machine into pieces of the desired weight, the gas in the dough is still further expelled. Before each piece can be moulded, the yeast must be afforded a chance to “recover” and to produce enough carbon dioxide gas to raise each dough piece so as to render the dough sufficiently pliable for moulding. Furthermore, after each piece of dough has been cut by the divider or by hand, its sides and edges are open, thus permitting gas formed by the continued action of the yeast to escape. Therefore, directly after dividing the dough, each piece is rounded or balled up so as to put a “skin” around it.

If there is no rounding machine available, this operation of course, must be done by hand. In either event, a minimum amount of dusting flour should be employed.

It can be readily seen that an enormous amount of time and labor can be saved through the use of dividing and rounding machines, and at the same time, much greater uniformity in the finished bread is thereby secured.

X. SHORT OR INTERMEDIATE PROOF

It is a serious mistake to send the dough directly from the divider to the moulding machine. Such practice is not at all conducive to the best quality in the finished loaf and should be avoided.

The individual pieces of dough being rounded should be allowed to rest, free from all drafts or chilling for about 10 to 15 minutes. During this period, the activity of the yeast will cause each ball of dough to increase noticeably in volume and to become softer, and more extensible,—and in this condition it will mould up nicely without breaking short. This short intermediate period of permitting the pieces of dough to rise or “recover” from the dividing process is accordingly called the short proof or sometimes, the “intermediate,” “preliminary,” “overhead” or “first” proof. It is poor policy to allow the pieces of dough to “short-proof” on the bench unless they are carefully covered and absolutely free from drafts so as to prevent them from drying out on the surface or crusting.

Various types of tray proofers are used especially for small doughs. These are usually suitably designed cabinets containing trays or drawers in which the pieces of dough are placed.

For larger doughs—overhead proofers are generally used. These are usually made up of traveling belts, cups or trays so arranged that the pieces of dough can be fed into them directly from the rounder. These traveling proofers are so constructed that the speed can be varied and in this way the time of “short-proofing” can be accurately controlled. Such equipment is encased and protected from drafts so that the desired temperature and humidity can be maintained.

XI. MOULDING

After going through the short proof process each piece of dough is moulded into a dough loaf. Today most bread is moulded by means of a machine especially designed for this purpose. Careful adjustment of the moulder is very important. Dusting flour is used to prevent the doughs from sticking in the divider, rounder and moulder,—but care should be taken to see that only the minimum amount is employed for this purpose.

XII. PANNING

In the making of pan bread, the dough loaves after being moulded are placed in the pans which have been very lightly greased. If the greasing is not uniform, the dough loaves are likely to stick to the pan, resulting in an ill-shaped, crippled loaf.

Some bakers make the mistake of using too much grease in the pan. Not only is this unnecessary extravagance and waste,—but an excessive amount of grease in the pan causes the outside of the loaf to actually “fry” in the oven instead of baking in the proper manner.

It is very important that pans of the proper size and shape be employed so as to conform to the type of finished baked loaf desired. If the pans used for any particular type of bread are not correct in size and shape,—the best quality loaf will hot result,—even though made from a good dough which has been properly handled up to the time of panning. New pans of course, should be carefully cleaned, greased and “burnt in” before using for baking. Otherwise there will be difficulty in securing the proper uniform “bake” and “browning” of the sides and bottom of the loaf on the loaves.

Bread pans should always be kept clean and in good condition. Every few weeks the pans should be cleaned in hot water containing about two ounces of lye to the gallon, so as to remove any excess grease or dirt. In doing this, however, extreme care must be taken to avoid burning the hands or clothing with the lye. After this treatment, the pans should be thoroughly rinsed two or three times in clean hot water and allowed to dry. These pans of course, should then be greased and “burnt-in” by placing in the oven similar to new pans before using again for baking purposes.

In panning it is important that each piece of dough is placed so that the seam faces the bottom of the pan and that the dough loaves are long enough to reach the ends of the pan.

In placing the pans of dough on the racks many bakers feel it advisable to load the upper shelves first and then work toward the bottom in order to avoid scraping any foreign material from the upper racks or outside of pans on to the dough loaves below which might happen if the reverse order of loading the racks were followed. However, in other instances where the temperature and humidity of the pan proofing box is not uniform throughout and the upper part of the proof box happens to be a little warmer than the bottom, the racks are loaded from the bottom to

the top—inasmuch as under these peculiar conditions the loaves on the top shelf would proof a little faster, and should therefore remain on the racks a slightly shorter period of time than the loaves on the lower shelves.

XIII.  PAN PROOFING

The moulding process naturally compresses each piece of dough or “knocks it down” thereby expelling a large amount of the gas. Before being baked it is necessary for the dough loaves to rise and attain proper lightness. For ordinary pan bread,—the dough loaves should be allowed to become at least double in size during proving. Therefore, the dough loaves after being panned, are placed in the pan proofing cabinet which is a well insulated metal or metal lined wooden chamber in which a uniform temperature of 90 degrees to 95 degrees F. and a relative humidity of 80 to 85% is maintained. At the temperature of proofing the yeast functions vigorously causing the dough to rise rapidly to the desired height in the pan and the relatively high humidity prevents the dough loaves from crusting. Under the conditions stated above, the pan proof period usually ranges from 30 to 60 minutes. This final proofing of the dough is very important and must be accurately controlled. “Many a good loaf is spoiled in the proof” is a true adage.

If a dough is underproofed, the gluten has not been stretched enough, and the resulting loaf will be small in volume, and somewhat soggy and heavy. On the other hand, if the dough has been excessively proofed, the gluten has been actually weakened through over-expansion and is in danger of dropping in the oven. Such a dough is not strong enough to spring up nicely in the oven under the expansion of the carbon dioxide gas and air in the dough during the first few minutes of baking. Therefore, over-proofed dough will result in a loaf of inferior volume, irregular shape, coarse grain and weak texture. Long proofing periods result in bread of inferior quality. If doughs appear to be very slow in rising in the pan proofing cabinet, the amount of yeast used should be increased.

Ordinarily “split-top” loaves are given one-half to two-thirds as much proof as regular plain top pan loaves.

Excessively high humidity in the proof box will cause drops of water to settle out on the ceilings and walls of the proof-box and the water dropping on the dough loaves causes unsightly spots and many cripples.

Excessively high temperatures in the proof-box as well as too prolonged a proofing period promotes the development of foreign organisms which weaken the gluten and produce sourness in the loaf. The regulation of the proper temperature and humidity to be maintained in the pan proofing cabinet is very important. Therefore a more detailed explanation of this subject is covered in Chapter XII.

A healthy dough containing liberal quantities of yeast and salt will always stand up best in the pans during the proofing process and naturally will produce the best quality loaf.

XIV. BAKING

A. THE CONVERSION OF DOUGH TO BREAD BY BAKING

Of course, it is perfectly obvious to everyone that the baking of dough which has been properly conditioned and fermented by yeast action, results in light porous bread which is an easily and completely digestible food. However, the exact changes in the dough during baking which brings about this remarkable conversion are perhaps not so generally understood.

1.  Oven Spring

During the first few minutes of baking the yeast functions more vigorously and more rapidly than at any previous stage in the bread making process. However, when the dough reaches a temperature of from 140 degrees to 150 degrees F., the enzymes of the yeast are killed and further production of gas ceases. During the first few minutes of baking, therefore, the dough rises very rapidly or in other words, attains what is familiarly known as oven spring. The expansion of the dough loaf in the oven is about equal to that secured in the proof box. This final rising of the dough loaves is the result of the following occurrences during the first few minutes in the oven:— (1) the rapid production of carbon dioxide due to the activity of the yeast, and—(2) the fact that a considerable amount of carbon dioxide gas produced in the dough prior to its entrance into the oven remains dissolved in the moisture of the dough and at the increased temperature of the dough in the oven,—this dissolved carbon dioxide is driven off, and aids materially in producing the desired “oven spring,”—and (3) the normal expansion of the carbon dioxide gas and air in the dough. The alcohol produced along with the carbon dioxide gas by the action of the yeast on the sugary constituents of the dough, is quickly evaporated by the heat and escapes from the dough into the oven in the form of vapor.

2. “Setting” of the Dough

After the dough has attained its oven spring in the manner described above,—the pliability or extensibility of the dough gradually becomes lessened and the dough becomes “set.” In other words, the dough is being baked or cooked and is gradually converted from dough into bread. This conversion is due to the fact that some moisture is driven out of the crumb of the loaf, some of the starch becomes gelatinized and the gluten and other protein becomes coagulated. This baked starch-gluten combination which includes within itself, the other ingredients of the dough, constitutes the light porous bread as we know it today.

3. Crust Formation

While the temperature of the oven is in the neighborhood of 400 degrees F.,—the interior of the dough loaf during the baking process rarely gets above 212 degrees F.  However, the outside of the dough is naturally heated much higher, dextrins are formed at outer surface of dough which act as a glaze or more or less brittle baked layer—familiarly known as the crust. The golden brown color of the crust is due to the toasting or carmelization of the sugar present.

4. Sterilization op Loaf by Baking

The heat of the oven is sufficient to kill all disease germs and in this way the finished baked loaf is sterilized. Therefore, in addition to being man’s best food, wholesome and completely digestible, bread is pure and clean.

B. TIME AND TEMPERATURE OF BAKING

The exact time of baking and oven temperature to be employed depends on the type and size of loaf being baked, and the manner in which it has been proofed. Usually oven temperatures for baking will range between about 375 degrees F. and 450 degrees F. In general, it may be stated that for ordinary 1 lb. loaves of pan bread one-half hour’s bake at about 425 degrees is about right. Larger loaves require a corresponding longer baking period and usually a lower baking temperature. “Old” doughs and doughs that have been excessively “proofed” need a higher oven temperature.

Flash heat in the oven is to be avoided inasmuch as such a condition causes a crust to form on the dough loaves before the inside is properly baked. Furthermore, flash heat will often cause an intense darkening in crust color which is very undesirable. The importance, regulation and measurement of oven temperatures is discussed more fully in Chapter XII.

In a properly baked loaf—the crumb is springy and when pressed down by the hand, the loaf will gradually spring back again. In an underbaked loaf, the crumb will be somewhat doughy and the loaf will not spring back when pressed down with the hand.

C. LOSS OF WEIGHT IN BAKING

The loss of weight of the dough loaf during the baking process is due mainly to the evaporation of moisture from the dough.

As explained in at preceding paragraph concerning dividing and scaling, one pound ordinary pan bread dough loses about 1^ ounces weight during baking. The baking loss for hearth bread is usually a little greater than that for pan bread. The actual loss in baking depends on the character of the dough when placed in the oven, the size and type of bread being baked and the general oven conditions. In general it may be stated that, the loss in baking is increased by:—

(1) improper baking temperatures

(2) lower humidity in the oven

(3) longer baking time.

Each individual can best determine his own baking loss and necessary scaling weight by actual observation and experience.

D. OVENS

1. General Remarks

The ovens used in the up-to-date bakery of today are remarkably efficient and represent a vast improvement over the type of oven used years ago. It is not within the scope of this book to describe the many various different kinds of ovens now in use. Briefly, ovens for bread baking may be divided into two main classes; first, those in which the loaves remain stationary after being loaded into the oven until removed after being baked, and second, those in which the dough loaves are transported or circulated thru the baking chamber during the baking process.

There are of course, different types of each of these classes of ovens. —The peel oven both of the stationary and portable types as well as the draw plate oven are examples of the first class.

The rotary, reel and traveling ovens are examples of the second class of ovens.

The traveling type of oven is one in which the floor of the oven is so constructed that it can move thru the baking chamber in the form of an endless belt. Thus the dough loaves can be loaded in at one end and are carried along thru the baking chamber and discharged at the opposite end. The temperature of the oven and speed of the traveling floor are so regulated that by the time the bread reaches the end of the oven it is completely baked.

Different types of ovens are constructed so as to conform to the type of fuel to be used, such as gas, coke, coal, fuel oil or electricity.

The fire box of the modern oven is of course, separate from the baking chamber, but so arranged that the heat will circulate properly around the baking chamber in order to give it the even heat required. The control of the temperature and humidity and the use of steam in the oven are discussed in Chapter XII.

Naturally the amount of bread or other bakery products which can be made within any given period of time is limited and controlled by the size and capacity of the ovens.

2.  Care in Loading and Unloading Oven

In removing the dough loaves from the proof box,—and in loading them into the oven, extreme care should be taken to avoid jarring the dough, inasmuch as the dough at this point is very easily knocked down and crippled for baking.

In loading a peel oven each pan should be placed on the peel so that the end edge of the pan is square or in line with the front of the oven. One half of the oven should be loaded first, working naturally from the rear to the front;—then the other half of the oven should be filled in the same manner. In removing the baked loaves, the half of the oven which was filled first naturally should be emptied first. The freshly baked loaves should be handled gently as they can be easily damaged by rough handling.

XV. COOLING AND WRAPPING OF BREAD

After bread is baked of course, it must be properly cooled before wrapping or packing for delivery. If bread is wrapped before it is sufficiently cooled there is considerable danger of the subsequent development of mold and rope in the loaf. A recent report of work done at The American Institute of Baking stated that the temperature of the interior of the loaf should be brought down to at least 95 degrees F. before wrapping.

Bread should be cooled gradually in order to avoid the cracking of the crust which is likely to result if the bread is unduly chilled directly after its removal from the oven. It is advisable to cool the bread in a fairly humid atmosphere in order to keep the loss of moisture from the loaves during the cooling as low as possible. In the winter time especially, it is quite often necessary to raise the humidity of the cooling room mechanically.

Of course, the exact time of cooling necessary depends on the actual temperature and humidity of the room. However, in general from one to two hours’ time is required. In the average bakery, bread will cool more rapidly in winter than in summer, and it is frequently necessary to cool the cooling room in the summer and warm up the same in winter.

Bread in smaller bakeries is most generally cooled by removing the freshly baked loaves from the pans and placing the loaves on racks. In loading these racks, it is advisable to fill the upper trays first and the lower trays last due to the fact that the temperature at the bottom of the rack of bread will be somewhat lower than at the top. Consequently, the loaves on the bottom will cool slightly faster.

When bread is cooled in this manner, it is usually advisable to keep the racks of hot bread in the oven room for about 15 to 20 minutes before removal to the cooling room which is considerably lower in temperature. Bread should not be wrapped if any condensed moisture has gathered on the surface of the loaf.

In some of the large bakeries, very successful cooling equipment in the form of special conveyors has been installed and frequently adequate provision is made for controlling the temperature and humidity of the air through which the loaves pass during the cooling process. In these cases, directly after coming out of the oven, the loaves are placed on the conveyor and are gradually cooled under scientific conditions just to the proper point for wrapping.