A Treatise on Baking

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Essential Factors Influencing Bread Quality

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Chapter XI

ESSENTIAL FACTORS INFLUENCING BREAD QUALITY

Section One—The Importance of Yeast, Salt and Cool Doughs

ESSENTIAL FACTORS INFLUENCING BREAD QUALITY
Section One—The Importance of Yeast, Salt and Cool Doughs

I. INTRODUCTION

The preceding chapter emphasized the importance of the proper selection and handling of the raw materials used in bread making and also described briefly the various steps involved in making and handling doughs in the commercial manufacture of bread according to modern methods.

Obviously the most important phenomenon in bread making is the fermentation and conditioning of the dough by the activity of yeast, the “Soul of Bread.” Because of this it has been rightly said that a thorough knowledge of dough fermentation and conditioning comprises the entire art and science of bread making. The complex and numerous changes which take place in the dough batch through the activity of the yeast are responsible for the conversion of the mixed mass of raw materials into a light porous dough which when baked, gives us leavened bread as we know it today.

In arriving at utmost efficiency in production, it is absolutely essential to maintain a healthy, vigorous fermentation of the dough. Therefore, the controllable factors which influence panary fermentation should be thoroughly understood by every baker so that he may properly regulate the same in order to attain the greatest efficiency in production.

In view of this, section two of this chapter has been prepared for the purpose of explaining in detail the science of dough fermentation and conditioning and the part played by the various dough batch ingredients and shop conditions in this connection.

Section one of this chapter contains practical information regarding the three main factors influencing dough fermentation, namely yeast, salt and temperature, together with the reasons why the liberal use of yeast and salt and the maintenance of cool dough temperatures represents the safest way of insuring the most economical production of high quality bread. Section one of this chapter also contains a brief description of the principal methods of bread making.

II. THE INFLUENCE OF YEAST SALT AND COOL DOUGH TEMPERATURE ON THE QUALITY OF DOUGH AND LOAF

The character of bread depends on the manner in which the dough is matured, ripened or conditioned. Experience has proven beyond a doubt that short time doughs in which the fermentation starts slowly but increases noticeably toward the end of the fermentation period and in the proof will always give the best results. This means a strong, healthy fermentation process made possible by the use of liberal quantities of yeast, the full amount of salt and the maintenance of cool dough temperatures.

A. LIBERAL AMOUNTS OF YEAST

The use of plenty of yeast naturally raises and conditions the dough quickly and to the best advantage, at the same time contributing flavor and food value to the finished loaf. The advantages of the use of plenty of strong yeast in the dough batch are further explained in section two of this chapter and also in Chapter IV.

B. FULL AMOUNT OF SALT

The use of 2% of salt has a very valuable effect in binding or strengthening the gluten so that it will hold the carbon dioxide gas and expand nicely without tearing, thus insuring good grain and texture in the finished baked loaf.

C. COOL DOUGH TEMPERATURE

While the temperature of the dough out of the mixer is important,—the temperature at which it matures is even more important. Keeping the doughs relatively cool, and using the full amount of salt but at the same time maintaining a vigorous, healthy fermentation will prevent the growth of undesirable bacteria and “wild” yeasts and the development of any excessive acidity in the dough which would weaken the gluten and result in a coarse dark loaf of poor flavor. Doughs in which the yeast and salt have been cut and where high temperatures are used, favor the development of these undesirable organisms.

III. DEFINITE ADVANTAGES SECURED THROUGH THE USE OF SHORT TIME COOL DOUGHS AND LIBERAL AMOUNT OF YEAST AND SALT

It may be interesting to know just how and why numerous advantages are secured by reducing the fermentation period through the liberal use of yeast, and at the same time maintaining cool dough temperatures and the full amount of salt.

A. A BETTER APPEARING LOAF

Due to the fact that less sugar is consumed and lost during the shorter fermentation period, more of it is retained in the loaf and the result is a better bloom.

Furthermore, the dough loaf is in a firmer, stronger condition and the oven spring is such that a more uniform and symmetrical loaf is secured than can be obtained from a dough which has undergone a prolonged fermentation.

In addition to this, due to the healthy firm condition of the gluten, a fine uniform grain and smooth velvety texture is secured.

B. BETTER FLAVOR

A loaf produced by a short time dough is sweeter and retains more of the natural blended flavor of the dough ingredients than a loaf produced from a long time dough, in which excessive acidity has developed thereby creating a slight sourness which is far from appetizing.

C. GREATER UNIFORMITY

The temperature of the dough during fermentation has a marked effect on the changes which take place in the dough in the trough. Control of temperature and humidity in the dough room is very essential to the production of good bread. During a short fermentation period in the average bakery it is much easier to keep the temperature and humidity under regulated control than it is over a longer period. In such cases, more uniform results can be secured from short time doughs than from long time doughs.

D. IMPROVED KEEPING QUALITIES

In a dough which is kept cool and which contains plenty of salt and liberal quantities of yeast, the water is more tightly and completely retained in the dough structure than in a dough where the gluten has been overdeveloped through a long fermentation period. Furthermore, the short time dough will retain more moisture during the baking and the resultant loaf will not stale nearly as quickly as a loaf made from a dough which has undergone prolonged fermentation.

E. INCREASED YIELD

Aside from the improved quality in bread, due to the maintenance of a short vigorous fermentation, the increased yield secured usually more than offsets the cost of the additional yeast required, thus effecting a real saving for the baker.

The increase in yield is due primarily to the following reasons:

1. Increased Absorption and Retention of Moisture

A greater absorption can be obtained in a cool dough. Less water is lost during fermentation and during the baking process from doughs that have been subjected to a short well controlled fermentation.

2. Decreased Fermentation Loss

Yeast acts on the sugary substances in the dough, and some of this sugar is consumed in furnishing the carbon dioxide gas which raises the dough.

In long time doughs, which are punched a greater number of times,

· more of this gas is lost. When it is remembered that this costs money and that for each pound of carbon dioxide produced, two pounds of sugar are used up, it can be easily understood that it is advisable to keep this loss of sugar as low as possible. The use of short time doughs accomplishes just such an economy. Furthermore, more moisture is naturally lost by evaporation from a long time dough than from a short time dough. Frequently the replacement of long time doughs with short time cool doughs will mean the reduction of a 3% loss during fermentation down to less than 1%.

F. SAVING IN TIME AND LABOR

The saving in time and labor made possible by short time doughs needs no explanation. It is obvious that it is distinctly advisable for every baker to avail himself of the opportunity to effect such an easy means of cutting down on overhead expense.

IV. LONG TIME DOUGHS AND REDUCED AMOUNTS OF YEAST ARE FALSE ECONOMIES, AND UNPROGRESSIVE

When the eating and keeping¹ qualities of the loaf are considered,—not to mention the increased yield of bread and the saving in time and labor,—the advantage of short time doughs whether made by the straight dough method or by the sponge and dough method are obvious. However, some bakers in their desire to minimize the cost of raw materials, have made the fatal mistake of believing that by reducing the quantity of yeast—increasing the dough temperature, cutting down on the salt and lengthening the fermentation period accordingly,—they will actually effect a saving. Yes, apparently there is a reduction in the mere cost of the materials put in the dough batch,—but this is a false saving and but a small part of the whole story.

It is interesting to note the statements made by a man who has spent considerable time in maintaining utmost production efficiency in one of the large and successful bakeries in this country:

“The wide awake baker has learned by years of experience that better Bread is made by the short process; that the slight additional cost for the Yeast is more than compensated for by the shortening of the time, saving of labor, higher absorption, increased yield, greater volume, improved quality of Bread and increased sales.”

He goes on to say:

“The eating of Bread made with plenty of Yeast creates the appetite for more Bread.”

V. TWO PRINCIPAL METHODS OF BREAD MAKING

The two different systems of bread making have been described in Chapter X from the standpoint of mixing and handling the doughs. However, a further explanation of these two systems may be of interest.

A. STRAIGHT DOUGH METHOD

According to this method of bread making,—the ingredients contained in the dough batch are all mixed together at one time and the entire dough is fermented and conditioned uniformly to the proper extent. This is the most modern and simplest method of bread making and when followed in the proper manner, produces a loaf having very definite desirable characteristics such as compact grain, a very pleasing sweet flavor, and improved eating and keeping qualities.

B. SPONGE-DOUGH METHOD

1. Explanation

This system of bread making is often termed the sponge and dough method. As the name indicates a part of the flour, water, yeast and sometimes sugary agents, shortening and Arkady are first mixed together to form the sponge which is allowed to rise and mature to a greater degree than a straight dough. After having matured to the desired extent,—it is then remixed together with the remainder of the ingredients. The final dough is then again placed in the trough and allowed to rise and condition for a short time and then made up in the regular way. By this method, the sponge part itself—from one standpoint,—is actually overaged and then mixed with the remainder of the raw materials and the entire batch then conditioned to secure the final degree of ripeness desired.

Bread produced by this method possesses certain characteristics peculiar to sponge doughs. The loaf is usually very soft, and quite large. The crumb is quite white, but its keeping qualities are usually inferior to those of a loaf made by the straight dough method. If a long time sponge is employed, the flavor of the loaf is apt to be slightly sour, and is usually considered much less desirable than the flavor of a loaf made from a straight dough. It may be interesting at this point to note the different types of sponge doughs.

2. Long Time Sponges

A long time sponge is one which is allowed to ferment for five to ten hours or longer. Years ago, long time sponges were quite generally used. However, at the present time they have been discarded by progressive bakers, because of the comparatively low yields and the inferior keeping quality of the bread secured, as well as the tremendous amount of time required to make bread by such a method.

3. Short Time Sponges

(a) PLAIN SPONGE AND DOUGH METHOD

Gradually with the growth of progress in the knowledge and science of bread-making, the old long time sponge method was replaced by straight doughs, due to the improved quality in the finished loaf and the saving in time and money effected. Then later studies concerning improved baking methods demonstrated, that by reducing the fermentation by the use of liberal quantities of yeast, but at the same time maintaining a goodly amount of salt and keeping the doughs cool, greater efficiency in production and a loaf of still better quality bread would be secured.

In those territories where the people seem to still prefer the “sponge” type of bread, bakers have found that similar benefits could be secured if short time sponges were used in place of long time sponges. Therefore, in those cases where the sponge and dough method is still being used, sufficient yeast should be used so that the sponge will mature in 3 1/2 hours or less. The advantages resulting from shortening the sponge time in this manner are so obvious, that no progressive baker employing sponge doughs would think of going to the old long time sponge after once using a 3 or 4 hour sponge.

(b) ARKADY SPONGE AND DOUGH METHOD

In making bread by the modern short time sponge and dough method, it has been found distinctly advantageous to include from ¼ to ½% of Arkady in the sponge and also 2% of yeast based on the total amount of flour employed, setting the sponge at a temperature of 74 degrees to 76 degrees F.

In part 2 of this book will be found an ideal Arkady sponge formula representing a three hour process and produces far better bread than can be secured from an old long time sponge and dough formula.

(c) SPONGE AND ARKADY DOUGH METHOD

In using Arkady in connection with the Sponge and Dough method some bakers prefer to add Arkady at the doughing stage instead of in the sponge. This can be done in a very simple manner. Merely set your regular short time sponge and add to the dough part ¼ to ½% of Arkady based on the total amount of flour used. Such a formula will be found in part two of this book.

VI. ADVANTAGES OF THE STRAIGHT DOUGH , METHOD

A. FLAVOR AND KEEPING QUALITIES

While a loaf made by the long time sponge and dough method may have good expansion and interior whiteness, it will lose its flavor quickly and by the time placed on the consumer’s table it will usually be found to be neutral in flavor carrying no appetite appeal. In general, the “eat-more” qualities of a good straight dough loaf will go far toward increasing the sales of bakers’ bread.

B. FLEXIBILITY IN HANDING DOWN IN THE EVENT OF A BREAK DOWN IN MACHINERY

1. Straight Dough Method Is Actually More Fool Proof Than Sponge and Dough Method

Many bakers seem to believe that the sponge and dough method is safer and more fool-proof or in other words that if a break down in machinery occurs, they can knock down the sponge and add more sugar and shortening and still produce a good loaf or at least a marketable product. Actually, however, in the case of a three or four hour sponge, there will be much more dough setting on the floor in the event of a break down than there will be if a two hour straight dough is used.

Furthermore, the straight dough can be put back into the mixer in exactly the same way as the sponge by adding the extra ingredients necessary to sweeten and freshen up the dough. In doing this, however, care should be taken to avoid mixing the dough too much thus breaking the gluten structure.

C. STRAIGHT DOUGH METHOD SAVES TIME, LABOR AND OVERHEAD EXPENSE

In a straight dough, all the ingredients for the dough batch are mixed together in one operation, forming one large mass of dough. However, by the sponge-dough method the total dough batch is made up in two operations and handled twice. In other words, the sponge is first mixed, placed in the trough and allowed to rise. It is then taken out, put back into the mixer “broken up” and mixed with the rest of the necessary ingredients to form the final dough which is again placed in the trough for a certain period before going to the divider and sealer. Double mixing requires more refrigeration,—a big cost factor. Thus, considerable extra work and expense is involved in making bread by the sponge and dough method.

VII. THE ESSENTIAL POINT IN MAKING QUALITY BREAD

The best common sense method of bread making so as to secure the maximum value from the raw materials used is to make a short time straight dough according to a good formula, taking the dough slightly on the young side, thereby producing a loaf of bread that has good eating quality, appetite appeal and builds up repeat orders. Such a system is not only simple and safe, but assures full value from all ingredients used. The success of a tremendous number of bakeries today has been due to the adoption of short time, cool doughs in place of the old, out-of-date long time doughs.

Section Two—Dough Fermentation and Conditioning

Section Two—Dough Fermentation and Conditioning

I. MEANING OF THE TERM FERMENTATION

A. SCIENTIFIC DEFINITION

Strictly speaking, fermentation is defined as the transformation of organic substances brought about through the agency of certain minute living organisms. According to this technical definition there are many different kinds of fermentation—the nature of each depending on the type of organisms present,—i. e. alcoholic, acetic, lactic, butyric, etc. The normal healthy fermentation of a bread dough is due to the desirable changes brought about by the yeast. This type of fermentation is termed: “alcoholic” inasmuch as the yeast breaks up some of the sugar present, forming the gas, carbon dioxide, which raises the dough and alcohol which readily vaporizes and vanishes from the loaf in the oven.

B. PANARY FERMENTATION

By years of usage the word fermentation in the bakery without further qualification has been popularly established to designate the fundamental chemical and physical changes brought about in the mass of mixed dough ingredients, by the presence and action of yeast.

In spite of this, and because of the fact that there are other types of fermentation known which are neither desirable nor common to bread making and which are caused by other organisms than yeast, the mere word “fermentation” is sometimes misconstrued to convey an erroneous and unsavory idea.

In order to overcome any possible confusion of this nature, the expression “Panary Fermentation” is frequently used to represent the essential changes in the dough batch—initiated and sustained by the action of the yeast.

II. HOW YEAST ACTIVITY BRINGS ABOUT THE PANARY FERMENTATION OF THE DOUGH

Dough fermentation and conditioning are brought about mainly by the action of the yeast enzymes in the dough batch. An explanation of enzymes and their action will be found in Chapter IV.

The activity of the yeast begins as soon as the dough is mixed and continues until killed by the heat of the oven in the baking process. The action of the yeast is often considered as two fold;— namely, the raising of the dough and the maturing or ripening of the dough. These two fundamental actions are explained in the following paragraphs.

A. PRIMARY ACTION—RAISING OF THE DOUGH This is mainly the result of the action of three yeast enzymes, and may be explained as follows:—

1. Invertase converts any cane sugar present into two simple forms of sugar, namely glucose, often spoken of as dextrose, and fruit sugar, known as fructose. These two simple sugars are directly fermentable by yeast. A combination of equal parts of dextrose and fructose is known as invert sugar.
2. Maltase converts any malt sugar present into fermentable dextrose.
3. Zymase acts on the invert sugar and dextrose breaking it up into gas, carbon dioxide, and alcohol.The carbon dioxide gas thus created throughout the mass of dough envelops itself in the gluten, expanding it, causing the dough to rise, and to become light and porous.

The evolution of carbon dioxide gas in the dough also contributes to the gradual creation of a certain small amount of acidity in the dough which in turn assists directly or indirectly in softening the dough and imparts necessary stretching qualities to it.

The alcohol produced along with the carbon dioxide gas evaporates readily from the dough and disappears from the dough loaf during the baking process. This alcohol, however, may exert a slight softening effect on the gluten.

In addition to the carbon dioxide and alcohol produced from the sugar by the action of the enzyme, zymase, there also is formed very small amounts of glycerin, succinic acid and other substances which undoubtedly contribute to the pleasing flavor of the finished loaf.

B. SECONDARY ACTION—CONDITIONING OF THE DOUGH

Dough may be considered to be made up of tiny particles of starch and gluten meshed together and combined with the yeast cells and other constituents of the dough batch.

The maturing, ripening, conditioning or mellowing of dough is due to the various changes brought about in the starch gluten combination by the action of the yeast, which results in softening the dough, making it more pliable. These changes not only impart extensibility to the dough and permit it to stretch under the pressure of the carbon dioxide gas without breaking short but also enable the dough to absorb and retain more water within itself,—in other words, the gluten becomes more completely hydrated. Thus, this action makes possible the spongy, springy character of the dough which results in light and easily digestible bread. This mellowing or conditioning of the dough occurs simultaneously with the production of the carbon dioxide gas which causes it to rise and to become light and porous.

While many people consider the so-called primary and secondary functions of yeast as independent actions,—a study of the situation shows that the two occur at the same time and actually overlap and merge.

The conditioning of the dough, largely dependent on yeast activity,—is discussed more fully in the following paragraphs.

III. EXPLANATION OF DOUGH CONDITIONING

A. INFORMATION LACKING REGARDING DOUGH CONDITIONING

It may be well to state here that complete and definite knowledge is lacking concerning just how and why this mellowing or ripening of the dough takes place. The results of research work done along this line have been somewhat conflicting. Undoubtedly, the liquefaction of some of the starch particles and the softening of the gluten which takes place during the fermentation period, are the causes for the softening or ripening of the dough.

Extensive research work is continually revealing new and essential knowledge concerning the Colloidal chemistry of dough. Much of this work shows definitely that the life and activity of yeast in the dough exert directly or indirectly a much more powerful influence in ripening the dough than was ever realized before.

B. THEORIES REGARDING DOUGH CONDITIONING

A brief resume of the situation, according to present day knowledge is interesting. Some authorities believe that dough conditioning is due chiefly to the direct action of the proteolytic enzymes contained in the yeast, and to some extent in the flour.

Others claim that the conditioning or mellowing of the gluten-starch combination in panary fermentation depends on the Hydrogen Ion Concentration or effective acidity gradually developed in the dough, either by its direct action or through the stimulation of diastase and the other enzymes present in the dough.

It is very likely, however, that both of these theories play an important part in the proper conditioning of bread doughs, during the panary fermentation process.

IV. HYDROGEN ION CONCENTRATION OF THE DOUGH EXPLAINED

A. DEFINITION

Hydrogen ion concentration means the intensity or degree of acidity irrespective of the actual quantity of acid present. Hydrogen ion concentration is the measure of actual effective active acidity and is expressed by the term: “pH.” The higher the pH number, the lower the actual active acidity and vice versa. For instance, a dough with a Hydrogen Ion Concentration of pH = 5.9 contains less active acidity than a dough of pH = 5.1.

At the time of mixing, most ordinary bread doughs possess a hydrogen ion concentration of about pH = 6.0 but as the fermentation of the dough progresses, this effective acidity is increased to about pH = 5.2 which appears to represent about the optimum condition for the dough according to the present commercial methods of bread-making. It is also significant to note that this development of acidity in the dough assists in preventing

the growth of “rope” and other foreign organisms which would act very detrimentally on the finished baked loaf.

B. DEVELOPMENT OF HYDROGEN ION CONCENTRATION BY YEAST ACTIVITY

The development of this effective acidity in the dough may be ascribed partly to the formation of the carbon dioxide gas, although recent research work indicates that part of the effective acidity in the dough is created slowly and progressively in some other much more obscure manner through the life and action of the yeast.

C. MECHANICAL ADDITION OF ACIDS CANNOT REPLACE ACIDITY DEVELOPED BY YEAST ACTION

It is significant to note that nature has endowed yeast with the peculiar power of creating a suitable hydrogen ion concentration in the. dough batch for the effective action of the various enzymes of yeast and flour. From a practical standpoint, it is impossible for the gradual mechanical addition of various acids in regulated amounts to satisfactorily replace the effective acidity produced gradually and steadily thru the natural functioning of the yeast.

D. RECOGNITION OF THE HYDROGEN ION THEORY

Although further research work is necessary in order to ascertain the exact nature of the changes taking place in the colloidal dough, which are responsible for dough conditioning—the Hydrogen Ion Concentration undoubtedly plays a large part.

V. RIPENING AND MATURING OF DOUGHS

A. WHEN A DOUGH IS “READY” OR PROPERLY MATURED

It is difficult to describe in words, just when a dough is ready or when it should be turned and when it should be sent to the divider.

A dough is said to be ready when the correct relationship between the conditioning of the dough and raising of the dough has been established through yeast action. In other words, the duration of the fermentation period should be so regulated that when the dough is sent to the divider, it will be in the best physical condition to pass through the make-up machines or to be made up by hand. This is very necessary if the desired loaf characteristics are to be secured in the finished bread. Naturally, the time at which a dough is “ready” or sufficiently matured in the trough depends on the rate of panary fermentation, which in turn is governed by the character and amount of ingredients used—the stiffness of the dough, the manner in which they are mixed, the temperature of the dough as well as the temperature and humidity of the dough room.

The appearance and “feel” of the dough indicates to the baker just when a straight dough should be turned or sent to the divider, and also the proper time at which a sponge should be remixed with the dough ingredients. These practical indications have been explained in Chapter X, and must be determined locally in each shop in order to insure proper ripeness of the fermented dough, so that it will be neither too young nor too old.

If a baker does not know the exact fermentation time to be employed in order to secure the best results in any given case, he can determine this by a series of laboratory scale baking tests. Each of these small test doughs should be mixed and allowed to ferment under exactly the same conditions with the exception that the fermentation period of each is different. For instance, one dough should be given a fermentation period which is judged to be correct according to the feel and appearance of the dough. One or two doughs should be given shorter fermentation periods and one or two doughs should be allowed longer fermentation periods. The difference between the fermentation period of each of these test doughs should be about 15 minutes, and an accurate record of these times should be kept. Each dough should be made up and baked in the regular way. Then by comparing all the finished baked loaves, the baker can easily determine which has been given the proper fermentation period.

B. YOUNG AND OLD DOUGHS

A “young” dough is one which has been insufficiently fermented and conditioned. Conversely an “old” dough is one which has been over-aged.

C. ADVISABILITY OF TAKING DOUGHS SLIGHTLY ON THE YOUNG SIDE

In modern bakery practice it has been found that the best resulting loaf is secured by taking the dough slightly on the young side. In this way fermentation losses are reduced and the resulting loaf will possess better eating and keeping qualities. In cases where poor bread is secured, the cause can often be traced to the fact that the doughs have been over-aged; thereby, producing a loaf poor in eating and keeping qualities.

D. CHARACTERISTICS OF DOUGHS WHICH ARE TOO YOUNG —AND RESULTING BREAD

While doughs taken slightly on the young side produce the best bread, they should not be “too young.” Doughs which are too young have been insufficiently matured and exhibit the following undesirable characteristics :

1. Toughness, but will break short if stretched.
2. Stickiness in make-up machines.
3. Slowness and stickiness in proof.
4. Crust colors rapidly and deeply in oven.
5. Difficulty in baking out properly.
6. Small oven spring.

The loaf produced from such a dough will have the following characteristics :

1. Small volume.
2. Dark reddish brown crust.
3. Sharp corners.
4. Crust blisters.
5. Coarse grain.
6. Yellowish crumb.
7. “Wild” breaks.
8. Blind split in split top loaves.

E. CHARACTERISTICS OF DOUGHS WHICH ARE TOO OLD—AND RESULTING BREAD

Old or over-aged doughs in general are indicated by the following:

1. Weakness of dough—breaks readily.
2. Stickiness in make-up machines.
3. Frequently starts to rise in oven and then drops.
4. Strong noticeable odor of dough.
5. Crust colors very slowly in oven.

The loaf produced from such a dough is usually characterized by:

1. Pale Crust.
2. Grey crumb.
3. Weak texture—crumbles easily.
4. Open grain.
5. Strong odor, poor flavor.
6. Poor keeping qualities.
7. Irregular break and shred.

VI. HOW YEAST IS NOURISHED AND ITS ACTIVITY SUPPORTED IN THE DOUGH BATCH

A. REQUIRED FOOD FOR YEAST ACTIVITY SUPPLIED BY FLOUR, SUGARY AGENTS AND ARKADY

In order to promote the normal and healthy activity of yeast, the following nutrition must be available:

1. Soluble nitrogen compounds.
2. Fermentable carbohydrates.
3. Essential Mineral Salts.

In the making of bread,—these necessary nutrients are furnished by the dough batch ingredients, mainly flour, malt extract or other sugary agents and added mineral salts such as Arkady. In order to be utilized by the yeast the substances supporting yeast activity must be available in the form of a solution, that is dissolved in some of the water of the dough so that they may diffuse or soak through the membrane of the yeast cells.

B. NITROGEN AND MINERAL FOOD SUPPLIED BY FLOUR, MALT EXTRACT AND ARKADY

The soluble nitrogen compounds required by the yeast are secured at the start from the small amount of soluble proteins normally present in the flour, from the malt extract if used, or from the addition of a suitable inorganic nitrogen compound supplied by Arkady, which furnishes a readily accessible and easily assimilable form of nitrogen food for the yeast stimulating its activity in the dough batch. As the fermentation of the dough proceeds the slow but steady development of active acidity together with possibly some proteolytic activity results in the progressive conversion of some of the insoluble protein of the flour which is inaccessible in that form as food for the yeast, into soluble substances such as peptones, which soak through the cell wall of the yeast plants, thereby supporting the life and activity of the yeast.

Mineral salts, such as compounds containing calcium, potassium, phosphates, ammonium substances and oxidizing salts are derived mainly from the flour, malt extract and Arkady. Arkady represents a definite mixture of mineral salts, prepared especially for use in bread making.

C. CARBOHYDRATE FOOD SUPPLIED BY FLOUR AND ADDED SUGARY AGENTS

The fermentable carbohydrate food necessary for the yeast is furnished by the natural malt sugar present in the flour and by other added sugary agents. The sugar dissolved in the water of the dough, diffuses through the outer membrane of each yeast cell into the interior where a very small portion of the sugar is actually assimilated by the yeast yielding heat and nourishment to keep it alive and active. A much greater portion of the sugar is attacked by the yeast and converted by the enzymes—invertase and maltase, into a simpler form of sugar, which is then acted upon by the enzyme—zymase, forming alcohol and carbon dioxide gas. These resulting products diffuse out through the cell walls of the yeast and the dough is raised by the carbon dioxide.

VII. THE EFFECT OF THE VARIOUS DOUGH INGREDIENTS ON PANARY FERMENTATION

A. YEAST

The character of the fermentation of any dough is primarily dependent on the strength and nature of the yeast itself. Other conditions being equal, the rate of dough fermentation is increased by the use of stronger yeast and decreased if weaker yeast is used. In like manner, the greater amount of yeast employed the more vigorous will be the resulting fermentation. Bakers’ yeast should not exhibit a “flashy” start in activity in the dough batch, but should bring about a healthy panary fermentation, which begins slowly and increases noticeably in vigor toward the end of the fermentation process, namely, in the proof box and oven, so as to yield the best character of bread.

It is a well established fact, that cutting down on the quality or quantity of yeast used in any dough is false economy. In his text-book “The Technology of Bread Making,” Professor Jago says:

“First select the strongest and purest yeast you can get for the money and don’t be afraid to use sufficient of it.”

The proper use of liberal quantities of strong yeast results in a greater yield of better bread and effects a considerable saving in time and labor.

B. FLOUR

As explained previously, much of the nutrition of yeast in the dough batch and the consequent support of its activity is derived from the constituents of the flour. In raising the dough, yeast conditions the gluten—stronger flours naturally requiring a more vigorous fermentation for proper conditioning than weaker flours. Shorter separation flour requires a shorter fermentation than longer separation flours. Different flours require different fermentation periods. With any new flour, the changes in fermentation desired can only be determined by a baking test.

C. SALT

Ordinary salt, technically known as sodium chloride, retards the fermenting activity of the yeast, thus decreasing the rate of dough fermentation. At the same time, however, salt promotes the development of a healthy fermentation by checking the growth and activity of any undesirable yeasts or bacteria which may have gained access to the dough batch. In this way salt exercises a valuable regulating effect on panary fermentation and the importance of the liberal use of salt and cool doughs from this standpoint alone can not be over-emphasized.

Salt strengthens the gluten. The effect accompanied by the softening of the gluten due to fermentation, imparts the proper resiliency to the dough, enabling it to hold and carry efficiently the water which it has absorbed. It is this combination of effects which gives the dough its ideal gas retaining properties and results in a strong healthy dough and fine textured high quality loaf. A general discussion concerning salt and its use in bread making will be found in Chapter III.

D. WATER

While in one sense water is not considered as a food supporting the activity of yeast, we must remember that the various nutrients supporting the yeast must be supplied in the form of a solution in order that they may soak through the membrane surrounding each yeast cell. It is only in this manner that these substances can be assimilated and utilized by the yeast. Water acts as the vehicle or carrier for the soluble protein, carbohydrate and mineral foods necessary for yeast activity and is therefore an indispensable factor in the nutrition of yeast. Slack doughs will ferment faster than stiff doughs.

The use of hard water necessitates a longer fermentation period, while

soft water has the opposite effect. The subject of water and the different kinds of water are discussed in Chapter II.

E. SUGARY AGENTS

As previously explained, sugary agents used in the dough singly or in combination, furnish the yeast with its necessary carbohydrate food and energy, and at the same time it is the sugar of dough which is broken up into carbon dioxide gas and alcohol by the action of the yeast enzymes thus raising the dough. The natural sugar content of the flour is very limited in amount and for most forms of bread, sugary agents must be added to meet the usual yeast requirements throughout the fermentation process and also to supply the necessary sweetness and other functions performed by sugar in bread making.

Malt extract is a most excellent sugary agent to use because in addition to its high content of malt sugar it also contains essential soluble protein and mineral salts which further stimulate yeast activity in the dough, and results in greater oven spring, improved symmetry in shape and better texture.

While a certain amount of sugar is necessary to support fermentation, and up to a certain point stimulates yeast activity in the dough, too great an amount will retard the rate of fermentation. If over 10% of added sugar based on the weight of flour is used in the dough, this retarding action is quite noticeable.

Since the upper limit of the amount of sugar is governed by the degree of sweetness desired, the amount of sugar added to an ordinary bread dough rarely exceeds 4%, based on the amount of flour used. However, for special sweet dough products, sugar in considerably larger amounts is most generally employed and naturally these doughs require more yeast than bread doughs to bring about the fermentation desired.

Doughs containing little or no added sugar must be given a shorter fermentation than doughs with larger amounts of sugar, so that there will be sufficient sugar present at the end of the fermentation period to support vigorous yeast action, and to impart the desired crust color to the loaf by carmelization during baking.

Milk sugar is not fermented by yeast.

F. SHORTENING

Shortening exerts no influence on the activity of the yeast in the dough batch, but is used mainly in improving the texture, keeping and eating qualities of the loaf. The yeast enzymes do not bring about any changes in the shortening.

G. MILK

While certain constituents of milk have a binding effect on the gluten, the presence of milk in a dough favors the development of a small amount of acidity which stimulates yeast action and tends to soften the gluten. Some recent research work at The American Institute of Baking has shown that in order to secure the best loaf from a dough containing 5%

of dry skim milk slightly more fermentation was required than in a non-milk dough. Hence a more vigorous fermentation made possible by slightly increased amounts of yeast is desirable in milk doughs.

Milk is a very important ingredient to use in bakery products due to the added nutrition, flavor and general eating qualities which it imparts.

H. MINERAL SALT BREAD IMPROVERS

A properly balanced combination of suitable mineral salts in the form of Arkady perform a useful function in bread making. These salts stabilize the water conditions and protect the flour from undue loss through fermentation, by supplying the yeast with its required nitrogenous and mineral nutrition. In this way, yeast action is assisted, the dough is conditioned in the most efficient and satisfactory manner, and the entire fermentation process made shorter and more vigorous, resulting in a greater oven spring, better bloom and texture. The amount of Arkady used should be carefully regulated, shorter separation flours requiring less Arkady than those of longer separation.

The maintenance of relatively cool dough temperatures is very advantageous and conducive to the best quality in the final loaf. This is especially true when Arkady is used.

VIII. THE SHOP CONDITIONS AFFECTING PANARY FERMENTATION

A. TEMPERATURE

1. Effect of Temperature on the Life and Action of Yeast

Yeast can be frozen without killing it. However, unless great care is exercised in properly thawing out the yeast, some of its cells will be ruptured and its action weakened accordingly.

From the freezing point up to 45 degrees F., the yeast is practically dormant and under proper conditions it can be kept at 45 degrees for a considerable length of time.

From this temperature up to about 95 degrees F., the activity of the yeast increases, but this action is very slow indeed below 65 degrees F.

From about 95 degrees F. up the fermentation power of yeast is gradually weakened and at about 140 degrees F. the enzyme, zymase is killed thus stopping the production of carbon dioxide gas and the raising of the dough.

2. Importance of Temperature Control in Bread Making.

Temperature is the foremost factor influencing the rate of activity of yeast in the dough batch. Within the limits shown above, higher temperatures speed up the rate of fermentation, while lower temperatures slow up fermentation. Thus the character of panary fermentation depends on the control of the dough temperature, from the time the dough is mixed until the yeast action is killed by the heat of the oven. Proper temperature regulation and the constant use of the thermometer is therefore absolutely necessary in order to insure satisfactory dough fermentation.

The maintenance of relatively cool dough temperatures during the fermentation period, together with the use of liberal quantities of yeast and salt, results in the optimum fermentation and conditioning of the dough and naturally the highest quality of bread.

In view of the importance of temperature in bread-making, this subject is treated more fully in the Chapter XII on “Temperature and Humidity in Bake Shop Operation.”

3. Dough Temperature to be Maintained

For ordinary straight doughs, experience has taught that the temperature of the dough out of the mixer should be from 76 degrees to 79 degrees F. If the sponge and dough method is used the temperature of the sponge part should be set at about 74 to 78 degrees F. Under set conditions, the temperature of the dough of the mixer can be regulated by the temperature of the water used.

The temperature at which the dough matures has even a more important bearing on the fermentation of the dough than the temperature of the dough directly out of the mixer. On standing in the trough a small amount of heat is developed by the active fermentation going on, thereby increasing the temperature of the dough accordingly.

The temperature of the dough when matured depends on the temperature at which it is set, the room temperature, the rate of fermentation and the duration of the fermentation period. With normal water conditions doughs should be set so that when fully matured and ready to go to the divider they will have a temperature of approximately 80 degrees F. Doughs set at precisely the same temperature will mature at different temperatures unless the temperature of the dough room is kept constant by means of adequate insulation and other facilities for accurate room temperature control. Ordinarily the dough room should be from 78 degrees to 80 degrees F.

Too high a dough temperature favors the development of undesirable bacteria which produce excessive acidity creating undesirable sourness in the loaf and undue weakening of the gluten resulting in a dark, coarse loaf of poor flavor. Excessively high temperature results in a sticky dough, requiring the increased use of dusting flour, lessened hydration, produces inferior eating quality and accordingly lower yields.

Too low a dough temperature means prolonged fermentation, giving some of the same undesirable results brought about by too high a dough temperature.

The proper dough temperature for optimum panary fermentation is one which permits the yeast to function vigorously but not high enough to stimulate the activity of foreign bacteria which produce undesirable forms of acid.

4. Proof Box Temperature

In the proof a more rapid rate of fermentation is necessary than in any of the preceding stages of the dough because the dough is divided into small units or loaves. This is brought about by the maintenance of higher temperature and humidity.

For most ordinary doughs the temperature of the proof box should be about 90 degrees to about 95 degrees F.

The strength of yeast is particularly important in the pan proofing process.

If the yeast is strong and vigorously active during the proofing process,—the normal “alcoholic” fermentation of the dough progresses very rapidly—preventing the functioning of any undesirable bacteria and wild yeasts, and results in a loaf of good quality.

5. Oven Temperature

During the first few moments the dough is in the oven the fermentation process is accelerated and the action of the yeast continues until its thermal death point is reached. This, together with the release of some carbon dioxide gas which was dissolved in the moisture of the dough, and the expansion of the air and carbon dioxide of the dough due to the increase in temperature results in the so called “oven spring.”

The exact oven temperature and time of baking to be employed depends on the type and size of loaf being baked. For ordinary baking purposes oven temperatures between 375 degrees and 450 degrees are maintained. A further discussion in this connection will be found in Chapter X and XII.

B. HUMIDITY

1. What is Meant by Relative Humidity and How is it Expressed

Humidity means the actual amount of water vapor contained in air. Relative humidity means the relative amount of moisture contained in air at a definite temperature in comparison with the amount of water vapor which air at that temperature is capable of holding.

2. How and Why Relative Humidity Influences Panary Fermentation

While perhaps not as prominent a factor as temperature the maintenance of a proper humidity in the bake-shop is necessary in order to secure quality baked goods.

Decreased humidity causes slower rate of fermentation.

Increased humidity causes a more rapid rate of fermentation, and it can be generally stated that for an average 3 hour straight dough a difference of 10% in relative humidity will influence the total fermentation time about six minutes.

Too low a humidity causes increased evaporation of water from the dough, resulting in a decreased yield and also results in the formation of a crust-like surface on the dough. This dried surface, when folded into the remainder of the dough batch does not ferment properly. This means that the rate and uniformity of panary fermentation is retarded and the result is the production of a smaller volume loaf as well as streaks and lumps in the finished bread. Such a condition means bread of inferior and less uniform quality. Too high humidity especially in the proof box causes tiny drops of water to condense on the surface of the dough, tending to produce stickiness of the dough and non-uniformity of the loaf. Thus the importance of properly regulated relative humidity can be readily seen. In view of the importance of humidity, its measurement and regulation, this subject is discussed more fully in Chapter XII entitled “Temperature and Humidity.”

3. The Proper Relative Humidity for the Bakery

(a) FERMENTING ROOM AND MAKE-UP ROOM

The correct relative humidity for the fermenting room is about 70 % to 75%. This should never drop below 65%. In the make-up room where machines are employed for this purpose the humidity should be lower so as to avoid any difficulty in handling the dough through the machines.

(b) PROOF BOX

A relative humidity of about 80 to 85% should be maintained in the proof-box. This may be secured by the introduction of wet steam at low pressure, or by means of humidifying equipment.

(c) OVEN

For most types of quality bread it is necessary to have the air in the oven in a moist condition. This will provide a more mellow heat and prevent moisture from evaporating too quickly from the dough loaf. This also prevents too rapid a formation of crust which would tend to retard the desired oven spring and result in a small volume loaf and a hard crust full of cracks.

The proper humidity in the oven depends on the kind of bread being baked, but for ordinary baking it usually is secured by the injection of steam under 5 to 15 pounds pressure. Steam is usually turned in the oven a few minutes before loading in the dough loaves and maintained only during the first few minutes of baking.

C. HANDLING OF DOUGHS IN THE PROCESS OF BREAD-MAKING

In addition to the materials used, the temperature, humidity and barometric pressure,—the manner in which the dough is mixed and handled greatly influences the fermentation and conditioning of the dough and the resulting bread. In other words, the time and speed of mixing, the folding and turning of the dough, the manner of dividing, rounding, short-proof, moulding, pan proof and the baking process all have a decided influence on the fermentation and conditioning of the dough and the quality of bread secured. In view of the importance of all these steps, they are described in detail in Chapter X.