Chapter 3 The baking process and dough mixing.
After reading this chapter, you should be able to
* present the 10 steps of the baking process.
* present an historical point of view of dough mixing and how it has evolved over time.
* explain the basic theory of dough mixing and the proper steps involved.
* explain the three main mixing techniques and understand their respective results on the dough and on the final products.
* explain the concept of strength and how it relates to the various mixing techniques.
* properly mix dough using the methods presented in this chapter.
This chapter begins with a brief overview of the baking process and continues with a detailed look at mixing.
THE BAKING PROCESS
The baking process can be defined as a natural and logical succession of steps that will ensure the proper transformation of basic ingredients into a loaf of bread. As detailed in Chapter 6, the baking process has a direct effect on the characteristics of the finished product.
When the baker accomplishes all of the steps properly, the integrity of the ingredients is retained and the loaf of bread has the right appearance and a very nice, complex flavor. If any of the steps are incomplete or ignored (especially mixing and fermentation time), or if the dough is handled the wrong way, the quality of the finished product will be diminished. (See Figure 3-1.)
[FIGURE 3-1 OMITTED]
Despite the evolution of baking technology, modern baking processes still follow the same basic steps as the traditional baking processes used for thousands of years. The traditional method starts with the elaboration of the preferment (a portion of the dough that is fermented and then added to the final dough) using natural yeast, like sourdough, or commercial yeast. Once elaborated, the preferment is allowed to ferment to develop the benefits that will be transmitted to the final dough and bread. When it is properly matured, the preferment is returned to the mixer and final dough mixing begins.
The dough is developed to its proper stage according to the final product characteristics described later in this chapter in Figure 3-23. Then, the dough is allowed to ferment in bulk for a period of time that is directly related to the mixing time and proportion of ingredients in the formula. Crucial to developing optimal flavor, bulk fermentation is considered to be the most important step of fermentation in terms of bread quality. During this process, the dough benefits from its own mass effect, and conditions are perfect to achieve the complete benefits of fermentation.
After the dough has properly matured, it is divided and preshaped according to its final weight and shape, and allowed to rest until final shaping. The shaped pieces of dough then go through the next fermentation step, where gas is produced by the yeast and trapped into the dough. This gas generates the typical volume and texture of the bread.
Once enough gas has been produced, the dough is scored and loaded into the oven. As the baking process begins, an important jumpstart can be noticed. Sometimes referred to as "oven kick," this is when the loaf reaches its final volume. After baking, the bread is unloaded and allowed to cool before it is packed or enjoyed by customers.
Even if complex pieces of equipment have replaced the baker's hands for certain operations, the same steps should be followed to create, ferment and make the dough evolve into its final presentation as a loaf of bread.
The remainder of this chapter provides the correct terminology for each step, and briefly explains what is happening during each.
This optional step in the baking process, which takes place before mixing, can be a very valuable tool for the baker to improve product quality. During preferment, a portion of the dough is allowed to ferment for a certain time in specific conditions. Then, it is added back into the final dough to improve its physical characteristics, as well as the appearance, flavor, and shelf life of the finished product. As described in Chapter 7, different kinds of preferment can be used according to the type of product and its required final characteristics.
Mixing is the first important step of the baking process. During this step, the baker combines all of the ingredients together to make the dough. Several important principles must be respected to achieve optimum quality for the dough and bread.
Also called bulk fermentation or floor time, first fermentation takes place when the dough is allowed to ferment as a large mass. This mass effect creates conditions that are optimum for the development of all of the benefits fermentation brings to the dough (see Chapter 4), including increased dough strength and development of flavor.
During the dividing step, the bulk of the dough is divided into small pieces according to the final weight of the bread and the weight loss that will occur during baking. For manual dividing, the baker must handle the dough very carefully to avoid damaging or disorganizing the gluten structure. Also, when cutting portions of the dough, an effort should be made to have one piece of dough, as opposed to many little pieces that have been put together to obtain the desired weight.
For mechanical dividing, the equipment choice is critical to preserve the precise weight, gluten structure, and gas retention that ensure the integrity of the dough. Hydraulic and stress-free dough dividers are preferred, because they minimize damage to the dough and maintain proper volume and crumb structure in the product.
In this step, cut pieces of dough are preshaped by hand or by machine using an automatic rounder. Preshaping is done with the desired final shape in mind; for example, loose balls are appropriate for short shapes like batards or boules, while rectangles are used for longer shapes like baguettes.
During preshaping, the strength of the dough can be adjusted if necessary. Weaker dough will benefit from a tighter preshaping that will reinforce the gluten structure, while stronger dough should be very gently preshaped. It is very important for the baker to carefully assess the dough characteristics and adjust preshaping accordingly. Over- or underworking the dough at this stage can be detrimental to final product quality.
Finally, the simple manipulation of preshaping will form a smooth "skin" on the outside of the dough that will promote proper and better shaping, as well as better crust characteristics.
Resting Time (or Intermediate Proof)
Between preshaping and shaping, the dough is allowed to rest (Figure 3-2) which allows the gluten to relax and makes it easier to work with during shaping. The intermediate proof continues to produce gas that will contribute to the cell structure of the crumb in the final products.
[FIGURE 3-2 OMITTED]
During resting, the dough should always be protected to avoid the surface drying that makes shaping very difficult. While it is easy to prevent drying, it is very difficult to rehydrate dough once it happens. Enclosed cabinets or plastic sheets are two options to protect dough from air drafts.
After a period of rest, the dough is formed to its final shape. This operation can be achieved by hand or by machine. At this stage, the baker should carefully judge the characteristics of the dough and adapt the hand shaping or adjust the machine settings accordingly. Weak dough should be shaped tighter, while strong dough will benefit from a gentler shaping. In fact, this is the last chance for the baker to modify the dough, if necessary, in order to get optimum product quality. For mechanical shaping, equipment that provides minimum pressure and stress on the dough should be selected. This will ensure maintenance of the gluten structure that provides great crumb cell structure after baking. (See Shaping Baguette Figure 3-3, Shaping Batard Figure 3-4, and Shaping Boule Figure 3-5.)
FIGURE 3-3 SHAPING BAGUETTE 11 1 The preshaped rectangle is ready for final shape. [ILLUSTRATION OMITTED] 2 By folding over the dough piece, the loaf is seamed. [ILLUSTRATION OMITTED] 3 The dough piece is ready to roll out. [ILLUSTRATION OMITTED] 4 The baguette is rolled out with both hands. [ILLUSTRATION OMITTED] 5 The final shaped baguette is complete. [ILLUSTRATION OMITTED]
This fermentation period takes place between shaping and the beginning of the bake. During final proof, the gas produced by the yeast will accumulate and create internal pressure on the gluten structure. Because of its physical properties, the gluten can stretch while maintaining its shape to create a loaf with great volume and a nice texture. The dough should also be protected during this stage to avoid surface dryness that can cause a thick, hard crust with poor, dull color. Enclosed cabinets or rack covers can be used to prevent dryness when bread is proofed at room temperature (or at a proper setting of the humidity level in a proof box). Linen is also used to maintain the right level of moisture on the loaves while proofing (see Figure 3-6), or a proofer-retarder with humidity control may be used.
[FIGURE 3-6 OMITTED]
After proper fermentation, the loaves are placed in the oven for baking. Oven loading can be done by hand, using an oven peel or loader, or with an automatic loading system for larger production. Several precautions should be taken to handle the dough as gently as possible to avoid deflation, and it is sometimes wiser to use a transfer peel to minimize damage during transfer from the proofing board to the loader. When loading, even spacing of the loaves is crucial to ensure the heat distribution necessary for an even bake and a uniform crust color on the finished products.
Scoring creates an incision on the skin of the dough. Scoring has a direct impact on the volume and final appearance of the bread, as desribed in Chapter 5.
Unloading the Oven
Unloading can be accomplished with an oven peel or with a loader. In either case, it should be done very carefully to avoid damaging the crust, which is very delicate and fragile at this stage of the baking process.
FIGURE 3-4 SHAPING BATARD 1 Perform the first fold for the batard. [ILLUSTRATION OMITTED] 2 Perform the second fold for the batard. [ILLUSTRATION OMITTED] A seam is created with the palm, and is now ready for final fold. After seaming with the palm, fold over the dough piece for final seam. [ILLUSTRATION OMITTED] FIGURE 3-5 SHAPING BOULE 1 The preshaped ball is ready for final shape. [ILLUSTRATION OMITTED] 2 Perform the second fold and tightening of the boule. 3 [ILLUSTRATION OMITTED] 4 Perform the second fold and tightening of the boule. [ILLUSTRATION OMITTED] 5 The final tightening of the boule is shown. [ILLUSTRATION OMITTED]
[FIGURE 3-7 OMITTED]
Bakers typically underestimate the importance of cooling (see Figure 3-7) and believe that the baking process ends when the bread comes out of the oven. However, the bread goes through a series of transformations during the cooling process. If the precautions described in Chapter 5 are not respected, quality can be compromised.
These 10 steps of the traditional method are required in order to bake bread. The quality of the final loaf depends on the attention to detail given to all of the steps.
THE DOUGH MIXING PROCESS
Many bakers consider mixing to be the most important step in the baking process. Although all the steps in the baking process are connected, and each is important, mixing is the first mandatory step in producing bread. For this reason, a great deal of attention must be given to this stage of the baking process.
Numerous functional and crucial dough characteristics, such as consistency, or level of hardness or softness of the dough system, and gluten development, also described as the formation of the structure of the dough and dough temperature, are determined during mixing. While analyzing what is happening when dough is mixed, this section of the chapter considers the following topics:
* Steps to follow for successful dough mixing
* What happens during mixing
* Precautions to take when mixing in extra ingredients
* Different mixing techniques and their applications
* How to determine mixing time
* Factors that affect mixing time
* What technique to choose in a production environment
FOUR CRITICAL STEPS OF DOUGH MIXING
Mixing is a procedure that can be divided into four important steps: scaling the ingredients, checking the temperature, incorporating the ingredients, and developing the dough. If all those steps are carefully achieved, the result will be properly mixed dough and a very consistent final product.
SCALING THE INGREDIENTS
Before mixing, it is important to scale all ingredients precisely. This first step might sound very simple, but it is definitely important because proper scaling will ensure a well-balanced formula and consistent end product.
MONITORING THE WATER TEMPERATURE
The temperature of the final dough is a critical factor in mixing, as it is directly related to the rate of fermentation. The ideal temperature to create an environment favorable for fermentation of most dough is 74[degrees]F (23[degrees]C) to 77[degrees]F (25[degrees]C). This is known as desired dough temperature, or DDT. If the dough is too warm, the yeast will move too quickly, and fermentation tolerance will be reached before the proper balance of strength and flavor has been reached. If it is too cold, the yeast will be very sluggish, and fermentation will take a very long time.
Several factors contribute to the final temperature of dough. These include the temperature of the room, flour, and water; the amount of heat created by the action of the mixer (also known as friction factor); and the temperature of the preferment, if one is being used.
The only temperature factor under the control of the baker is the temperature of the water, as the temperature of the room and flour are typically already set. As for the friction factor, it will vary depending on the type of dough and type of mixer used. To calculate the friction factor, first find the number of degrees the dough will rise when mixed in second speed for one minute. Then, multiply this number by the number of minutes the dough will be mixed in second speed. This test should be done on the first dough of the day and logged. It can then be applied to the remaining dough mixed during that day. The average friction factor for a spiral mixer is 2[degrees]F (3.6[degrees]C) per minute of mixing. When working with a planetary mixer, some experiments might be done to find the right mixing friction factor. No precise factor can be provided, as the size of the bowl and shape of the dough hook will affect the mixing friction factor.
The following example illustrates the process used to determine the correct water temperature required to arrive at the DDT In this example, the room and flour temperature is 65[degrees]F, the friction factor is 8[degrees]F, and the DDT is 75[degrees]F In this example, no preferment is used.
To find the base temperature, multiply the DDT by the number of factors contributing to that temperature: 75[degrees]F X 3 = 225[degrees]F The friction factor is not included in the average because it is not a temperature but a value that designates a change in temperature. The known temperatures can then be subtracted from the base temperature to determine what the water temperature should be.
CALCULATION Base Temperature 225[degrees]F Less Room Temperature -65[degrees]F Less Flour Temperature -65[degrees]F Less Friction Factor - 8[degrees]F Water Temperature 87[degrees]F 225[degrees]F -(65[degrees]F + 65[degrees]F + 8[degrees]F) = 87[degrees]F
If all the temperatures are accurate, and the friction factor has been determined properly, using 87[degrees]F (22[degrees]C) water will yield dough with a final temperature of 75[degrees]F (24[degrees]C).
If a preferment like sourdough is used, it must be considered as a fourth factor in the calculation. The DDT is multiplied by four instead of three (75[degrees]F X 4 = 300[degrees]F), and the preferment temperature is subtracted from the base temperature.
CALCULATION Base Temperature 300[degrees]F Less Room Temperature -65[degrees]F Less Flour Temperature -65[degrees]F Less Preferment Temperature -68[degrees]F Less Friction Factor - 8[degrees]F Water Temperature 94[degrees]F 300[degrees]F - (65[degrees]F + 65[degrees]F + 68[degrees]F + 8[degrees]F) = 94[degrees]F
If all the temperatures are accurate and the friction factor has been determined properly, using 94[degrees]F water will yield dough with a final temperature of 75[degrees]F
It is important to remember that this formula should only be used as a guideline. A log should be kept in the bakery to record temperatures, so that there is a guide to follow and any changes are noticed immediately. This will allow adjustments to be made before the consistency of the final product is jeopardized.
INCORPORATING THE INGREDIENTS
Ensuring Clean Equipment
Next, it is necessary to make sure that the mixer bowl and hook are clean. It takes just a few seconds to clean scraps of dried dough that are still stuck to the bowl, which, if left, may not dissolve properly into the next dough and leave a hard lump in the final product.
Adding Ingredients to the Mixing Bowl
Finally, in order to prevent changing the weight of the flour, add it to the bowl first, followed by water and the other ingredients. Following this order is important because formulas are designed in baker's percentages, where all the ingredients are based on the total weight of the flour. For example, if the water is added before the flour, and the dough is too soft, more flour will have to be added. Because all the other ingredients were calculated on the original weight of the flour, if the quantity of added flour is fairly large, the formula will be out of balance.
For dough mixed in a planetary mixer or a mixer without a bowl-reverse option, if flour is placed in the bowl first, some of it might get stuck in the bottom without being incorporated into the dough. One way to prevent this problem is to add half of the water first, then all of the flour and the rest of the water, until the proper dough consistency is achieved.
When the ingredients are scaled and the water temperature is determined, flour and water are placed in the bowl and the mixer is turned on at first speed for incorporation. If preferments are used, they should be incorporated into the dough at this stage. Depending on the type of preferment (high or low hydration), the consistency of the dough might be changed, and some water adjustments may be necessary. During the next 3 to 4 minutes, flour, water, and preferment will be combined by the mechanical action of the mixer's dough hook. During this time, the baker must carefully watch the consistency of the dough to determine if more water is needed, as this is the best time to add it.
When mixing a formula for the first time, it is better to hold back some of the water just in case the flour used has a lower absorption. If needed, the withheld water can be added to obtain the desired consistency.
When the proper consistency is achieved, two options are possible. The baker can continue mixing and incorporate the other ingredients of the dough, such as fresh yeast and then salt. The other option is to "autolyse" the dough.
The autolyse is a process developed by Professor Raymond Calvel, a French Master Baker known for his in-depth studies of the dough system wherein the flour and water are mixed and rest for a minimum of 15 to 20 minutes. During this time, two important reactions happen in the dough. First, the proteins of the flour become better hydrated, leading to better gluten structure properties of strength and gas retention. The second is a natural action of a specific enzyme called protease, which is naturally present in the flour. In general, an enzyme is an organic component with a specific and natural action of degradation. Proteases are responsible for protein degradation. When allowed enough time to work, they will react on the protein and degrade some of the gluten bonds. As a result, the dough will become more extensible, and its machinability will be improved.
A minimum of 15 to 20 minutes is necessary to provide sufficient time for the activation of the enzymes. Autolyse can last up to 1 hour for the bulk of the dough. Another option is to autolyse only a portion of the dough made with a portion of the total flour for the formula but for a longer period of time (in general, 8 to 12 hours or overnight). The autolysed portion of dough is returned to the mixer the next day, and mixing resumes in a normal way. This technique allows the baker to get the benefit of the autolyse without having to stop the mixing process to wait for the enzymatic activity to happen.
Yeast, salt, and stiff preferments are added to the dough after an autolyse because both ingredients work to counter its effects. Salt slows the action of the proteases of the flour, while the fermentation process initiated from the yeast creates acidity that increases dough strength and decreases extensibility. Extensibility could be described as the property of the dough to elongate easily or not under a stretching action.
Special Considerations for Autolyse One important exception to the no-yeast-before-an-autolyse rule is when using dried instant yeast. In this case, it is better to incorporate the yeast with the flour for 1 minute at the beginning of the mixing time because the cells in dried instant yeast have a low water content and require more time for rehydration. If incorporated late in the process, they will not completely dissolve into the dough and fermentation will be negatively affected.
The same principle can be applied for an autolyse. Because mixing time is reduced, it is better to incorporate the dry instant yeast just before the autolyse. By the time the cells are dissolved into the dough, the autolyse time will be almost over and the fermentation of the dough will still be minimal.
Liquid preferments like poolish or liquid levain must be incorporated at the beginning of the mixing process even if an autolyse is done because their low yeast content won't really affect dough strength. How ever, stiffer preferments with more yeast, such as prefermented dough, should be incorporated after the autolyse.
Technically speaking, when no autolyse is made, flour, water, yeast, and salt can be incorporated at the beginning of mixing. Despite the common belief that salt will kill the yeast, no change will happen in the dough or bread characteristics. The salt and yeast are in contact in the dough for 4 to 6 hours after mixing, so if something negative were to happen, there would be plenty of time.
However, in order to have a better control of ingredient incorporation and to make sure that nothing has been forgotten, it is better to follow a standard procedure when adding ingredients into the dough. For example, if the baker always adds yeast and then salt before going into second speed, there is less chance of error.
[FIGURE 3-8 OMITTED]
DEVELOPING THE DOUGH
When all ingredients are well incorporated and proper dough consistency has been achieved, the baker proceeds to the next step: dough development (see Figure 3-8). Depending on desired gluten development, this step can be done in first or second speed. A long mixing time in second speed is used for well-developed dough, and a short mixing time in first speed is used for underdeveloped dough. The method used will be determined by the desired characteristics of the final product. More precise guidelines will be presented later in the chapter.
Because fermentation activity is dependent on the temperature of the dough, the baker should confirm that the desired temperature has been reached. If the temperature is good, the baker can follow the regular baking process. If it is too cold, the first fermentation time will need to be lengthened; if it is too warm, it should be shortened. These differences should be taken into consideration for the next batch of dough by increasing or decreasing the water temperature.
A common mistake made by many bakeries is to continue mixing when the temperature of the dough is too cold. While the extra friction created by this process will warm up the dough, the extra mixing time will also continue to develop the gluten of the dough. The end result may be the desired dough temperature, but the dough will likely be overdeveloped, creating gluten with an excess of extensibility (due to the breaking of some gluten strength) and a lack of elasticity. Elasticity is the property of dough to retract to its initial position after being stretched. The dough will also be sticky and very difficult to work with, and the final product will have the tendency to be flat, with a dense inside and little cut opening. Adjusting the first fermentation time is a much safer procedure, and is strongly advised.
Physical Changes During the Formation of Dough
As soon as flour and water come into contact, the water hydrates the flour components, which are primarily starch and protein. The two main types of starch are native starch and damaged starch. The structure of the native starch remains the same, but the structure of the damaged starch has been broken during the milling process. The native starch absorbs water on the outside of the particle only, while damaged starch absorbs close to its own weight in water. Both play the role of filling agent in a dough system.
The two primary proteins in wheat--glutenin (protein that will have some effect on the elasticity of the dough) and gliadin (protein that will affect the extensibility of the dough)--are responsible for the formation of the dough. Depending on their quality, these proteins can absorb 200 to 250 percent of their weight in water. As they inflate, they become attracted to each other and form chains of proteins called gluten. (See Figure 3-9.)
[FIGURE 3-9 OMITTED]
After the gluten has formed, the mechanical operation of the dough hook will work it into an organized structure through two distinct movements. The first stretches the chains of gluten, while the second folds the chains over onto themselves. After a period of mixing, these chains become longer and longer, finer and finer, and more and more overlapped. This creates the three-dimensional gluten structure of the dough.
A longer mix will generate a well-developed gluten structure, while a shorter mix will generate an underdeveloped one. Care must be taken to prevent mixing for too long, as it will stretch the gluten chains to the point where they will break. This is called overmixing the dough.
Due to the overlapping and better organization of the gluten chains, the structure of the gluten will get stronger, and a noticeable change in the dough rheology (properties of the dough to deform and flow during the baking process) can be observed. (See Figures 3-10 and 3-11.) Visco-elastic properties will develop, or, more simply, the dough will become less extensible, more elastic, and able to trap and retain gas.
[FIGURE 3-10 OMITTED]
Protein Hydration and Mixing Time in First Speed Protein hydrates at a slower pace than starch, which makes it necessary to mix in first speed for at least 5 or even 6 minutes for a larger batch of dough to ensure a good gluten quality. If the mixer is switched to second speed too early, it may start to organize gluten that is barely created, and the overall gluten development of the dough will be negatively affected.
Chemical Changes During the Formation of Dough
When water is introduced into the mix, the two main natural chemical reactions are fermentation activity and enzyme activity. The rate of these reactions depends on the quantity of water used. For example, wet dough will generate faster fermentation activity. Consequently, the level of yeast needed in the formula in order to maintain control may need to be reduced over the process.
[FIGURE 3-11 OMITTED]
Oxidation of the Dough Another important chemical change that happens during mixing is dough oxidation. Oxidation occurs when naturally occurring oxygen is incorporated into the dough during mixing. Most of the effects from this reaction are positive. As the oxygen chemically reacts with the molecules of protein, better gluten bonds are formed; they reinforce the gluten structure and the tolerance of the dough.
If the dough is overmixed, too much oxygen will be incorporated, and the carotenoid pigments (natural components of the kernel of wheat that are responsible for the creamy color of the flour and some aroma production) will be negatively affected. Too much oxygen will deteriorate these pigments and automatically lead to a final product with a whiter crumb color and a blander flavor.
Although too much oxygen is bad, some is necessary. The micro cells of air that are introduced into the dough system during mixing play an important role later in the baking process by forming the core of the crumb structure. During fermentation, the gas produced by the yeast accumulates in these micro cells and forms the cell structure of the crumb or alveoles.
FIGURE 3-12 INCORPORATION OF FAT 1 A large percentage of butter is added at the end of dough development. 2 The butter should be pliable to be incorporated properly. 3 At 80 percent incorporation, small butter chunks still remain on the surface of the dough. 4 At 100 percent incorporation, no butter is visible.
To minimize the negative effect of oxidation, the baker can utilize salt's natural property of slowing down chemical reactions (which is why it is used to increase the shelf life of foods like cured meats or salted fish). By incorporating salt into the dough at the beginning of the mixing time (while the mixer is still in first speed), the oxidation process will be retarded. Conversely, should the baker want to achieve a very white crumb structure, the incorporation of the salt must be delayed, but flavor will also be penalized.
Incorporation of Secondary Ingredients Into a Dough System
Even though we cannot discuss every ingredient added to dough in every bakery, some observations about primary ingredients will be helpful.
Incorporation of Fat A small percentage (2 to 4 percent) of solid fat, such as butter or margarine, can be incorporated with the flour and water at the beginning of mixing. A larger percentage (5 to 15 percent) of solid fat should be incorporated when the dough is halfway through development (in general, at the middle of the second speed time). An earlier incorporation (at the beginning of the mixing time) will "lubricate" the chains of proteins, delaying the bonding and development of the gluten.
More than 15 percent solid fat should be incorporated when the gluten is almost fully developed. This will ensure a strong dough structure that is able to support this massive incorporation of fat. (See Incorporation of Fat Figure 3-12.)
Liquid fats, like oil, are in general part of the hydration of the flour and should be incorporated into the dough at the beginning of the mixing time. If a large quantity of oil is required, it can also be incorporated after the full gluten development (very slowly in first speed).
Incorporation of Sugar A small amount of sugar (up to 12 percent) can be incorporated into the dough at the beginning of the mixing time. Higher levels should be incorporated in several steps. Because it is a hydroscopic ingredient, sugar will absorb a lot of water. If too much sugar is introduced to the dough at once, it may take some water away from the protein and disorganize the whole gluten structure.
When levels of sugar are very high (20 to 30 percent), some bakers use the same technique as for a high level of butter, leaving it out of the dough until the gluten is well developed.
Incorporation of Eggs Eggs should be incorporated at the beginning of the mixing because they play a major role in the hydration of the flour. Even though some formulas only call for eggs to hydrate the flour, they don't have the same flour hydration characteristics as water. To ensure a good gluten quality, at least 10 percent of water should be added in addition to the eggs. The final product will have a lighter, moister crumb texture.
Incorporation of Dry Ingredients Ingredients like malt or milk powder can be incorporated with flour and water at the beginning of the mixing time.
Incorporation of Solid Ingredients Like Nuts, Dry Fruits, and Chocolate Chips
Any chunky ingredients that won't dissolve into the dough must be incorporated at the end of the mixing time. After the gluten has been properly developed, turn the mixer to first speed and gradually add the ingredients until they are well distributed into the dough.
This gentle incorporation will have two positive effects for the dough and the bread. First, the added ingredients will stay intact within the dough. Second, incorporating the ingredients in a gentle way will reduce damage to the gluten structure. If second speed is used, the ingredients will act like razor blades into the dough and cut all the gluten bonds that were formed during mixing. (See Incorporating Solid Ingredients Figure 3-13.)
MIXING PROCESS CONCLUSION
Mixing dough involves four distinct stages: scaling the ingredients, checking the temperature, incorporating the ingredients, and developing the dough. Following these steps with precision and attention to detail typically results in properly mixed dough and a predictable, consistent final product.
A thorough knowledge of the various mixing techniques used for bread production is essential to consistently achieve desired results for different products. The goal of the second half of this chapter is to describe the different mixing techniques used in bakeries and to discuss how bread quality can be changed depending on gluten development. The three main mixing techniques covered in this chapter are short mixing, intensive mixing, and improved mixing. In addition, there is a brief discussion of the double hydration technique used for super-hydrated breads.
FIGURE 3-13 INCORPORATING SOLID INGREDIENTS 1 Mix on first speed when adding nuts into dough. 2 At 80 percent incorporation, the nuts are still showing on the surface.
To understand the three main mixing techniques, it is necessary to examine the recent history of baking. Before mechanical mixers became widely available 50 to 60 years ago, bakers mixed their dough by hand. The energy provided to the dough during hand mixing is not sufficient to accomplish a lot of gluten development; in fact, the resulting gluten structure is very underdeveloped. To complete gluten development and make the dough strong enough for shaping and proofing, a long fermentation time is necessary. This entire process is referred to as a short mix.
After World War II, mechanical mixers increased in availability. The first mixers were very basic, running only with one speed. Mixing was still very gentle and gluten was underdeveloped. When faster, two-speed mixers became available, bakers realized that the more intensive development of the gluten enabled them to reduce the first fermentation time. This brought up an interesting point: Producing more bread during one shift meant more sleep. Also, consumers of the time enjoyed bread with a large volume and a white crumb. This convergence led to the creation of the intensive mix technique, which is characterized by a long mixing time with short first fermentation.
As time passed, consumers began to notice that the flavor of bread was lacking, and staling was happening much faster than before. At first, they pointed the finger at mechanical mixers, blaming the baker and the machinery for the changes. However, with the evolution of the science and a better understanding of the baking process, it has become clear that the mixers themselves were not responsible for the lower bread quality. Instead, it was the way the mixers were used.
By mixing the dough until full development, two major factors were created that compromised bread quality. The first was overoxidation of the dough, which led to the whiter crumb and a blander flavor. The second was related to the fermentation activity of the dough. By reducing the first fermentation time to almost zero, acidity was given no time to develop, aromas were not created, and shelf life was considerably reduced.
In order to sell a larger quantity of higher-quality bread, bakers started to think about ways to improve the baking process. Of course, giving up on mechanical mixers and returning to hand mixing was out of the question. With the help of baking's scientific community, the improved mix method was created. This technique improves the quality of the bread by reducing the mixing time in second speed. As a result, gluten isn't fully developed and dough still requires some first fermentation time to gain strength.
This technique completes two positive actions: The shorter mixing time limits oxidation and preserves the integrity of the wheat kernel, and the longer first fermentation develops acidity that increases the product aroma and shelf life.
Today's bakers still have a choice of techniques when mixing dough. The following sections describe each technique more precisely and explore their effects on final product characteristics.
SHORT MIX DESCRIPTION
Short mix, the gentle mixing method that utilizes first speed only, most closely approximates the characteristics of hand mixing. Short mixing incorporates the ingredients and does very little gluten development, resulting in an underdeveloped gluten structure and a long fermentation time (see Figure 3-14). Typically, two to four folds are necessary during the first fermentation to develop strength (see Folding the Dough Figure 3-15). Because good extensibility is needed for easy dough folding, a soft dough consistency is preferable. Also, due to the long first fermentation, a low percent age of yeast must be used. At the shaping stage, dough is fairly gassy and soft, but it is still easy to work with.
SHORT MIX EFFECTS ON BREAD CHARACTERISTICS
Short mixing creates almost no oxidation, resulting in a very creamy crumb color. Due to the low development of the gluten, the crumb cell structure will be open and irregular as gas accumulates in uneven air pockets in the dough. In addition, the long first fermentation will produce a great deal of acid, greatly enhancing the flavor and shelf life of the final product. Finally, because the gluten is not well organized, it won't retain much gas, and the volume of the bread will be slightly reduced.
[FIGURE 3-14 OMITTED]
INTENSIVE MIX DESCRIPTION
During intensive mixing, ingredients are incorporated in first speed, and the dough is developed to the maximum in second speed. It is a fast, efficient mixing method that produces dough that runs easily through heavily mechanized processes.
Intensive mixing produces a stiff, fully developed dough that is strong enough to shape almost immediately. The typical length of bulk fermentation is limited to 15 to 20 minutes and is, in fact, more of a resting time than fermentation time. For some dough, a too-long first fermentation after mixing automatically results in an excess of strength and a dough that is difficult to work with. (See Figure 3-16.)
FIGURE 3-15 FOLDING THE DOUGH 1 Partway through the first fermentation, the dough is very extensible. [ILLUSTRATION OMITTED] 2 Turn the dough out onto a floured table and fold over one-third of the dough from the right. [ILLUSTRATION OMITTED] 3 Fold the dough from the left side. [ILLUSTRATION OMITTED] 4 Fold the dough from the front to the back. [ILLUSTRATION OMITTED] 5 Fold the dough from the back to the front. [ILLUSTRATION OMITTED] 6 The short mix dough now has one complete fold. [ILLUSTRATION OMITTED]
INTENSIVE MIX EFFECTS ON BREAD CHARACTERISTICS
A long mixing time automatically incorporates more air into the dough, increasing oxidation and its negative effects, including a very white crumb color. Due to the full gluten development, the cell structure of the bread is very tight and regular, creating a crumb structure with a very even grain. In addition, the perfect organization of the gluten structure retains a lot of gas into the dough system, resulting in a fairly large volume of the final product. Unfortunately, flavor profiles and shelf life are much diminished due to the very short first fermentation time involved.
[FIGURE 3-16 OMITTED]
IMPROVED MIX DESCRIPTION
The improved mix is a compromise between the short mix and the intensive mix. It allows the baker to achieve more of the efficiencies of intensive mixing, while retaining most of the product quality obtained with a short mix method.
With this technique, ingredients are incorporated in first speed, and dough is mixed to half development in second speed. Dough consistency should be medium soft (extensible enough), since the strength of the dough will increase even more during the fairly long first fermentation. The dough obtained will be perfectly adapted for hand shaping or a semi-mechanized process. (See Figure 3-17.)
[FIGURE 3-17 OMITTED]
IMPROVED MIX EFFECTS ON BREAD CHARACTERISTICS
The gentler mixing process in this technique helps to retain a creamy color and open crumb, while longer fermentation results in a more flavorful product with a good shelf life. Volume is a compromise between the smaller loaves characteristic of a short mix and the larger ones achieved by an intensive mix. (See Figure 3-18.)
[FIGURE 3-18 OMITTED]
The end of the 1990s saw the growing popularity of super-hydrated dough like ciabatta, pugliese, and francese. To mix these types of dough in a large production environment, another method called the double hydration technique can be used.
The double hydration technique involves incorporating water in two phases. First, enough water is incorporated at the beginning of the mixing time to make a medium-soft dough consistency. Then, the dough is mixed, and the gluten is developed. Once the gluten reaches approximately two-thirds of its full development, the rest of the water is added little by little, until it is well incorporated into the dough. (See Double Hydration Technique Figure 3-19.)
FIGURE 3-19 DOUBLE HYDRATION TECHNIQUE 1 For the double hydration technique, water is added once the gluten is developed. 2 Water is added in stages to achieve full incorporation. 3 After incorporating all the water, the dough is very wet but has a well developed gluten structure. 4 Shown here are the crumb and crust of ciabatta made using the double hydration technique.
Double hydration can create a very soft dough with sufficient strength for machinability. This technique works well when using equipment that uses stress-free technology, which requires good machinability properties like good flow and strength.
HOW TO CALCULATE MIXING TIME
For each mixing technique, the baking scientific community has developed guidelines to determine the amount of mixing time required to obtain the desired gluten structure. These guidelines are based on the movement of the dough hook during mixing and its effect on gluten organization. Because each movement or revolution stretches and folds the gluten, it is necessary to know the number of revolutions needed for appropriate gluten structure.
For gluten structure for a short mix, the hook needs to make 600 revolutions in the dough in first speed. For an improved mix, 1,000 revolutions of the hook in second speed are needed. Intensive mix requires 1,600 revolutions of the hook in second speed. Each of these calculations takes into account the fact that all ingredients have already been incorporated and the gluten formed before the number of revolutions begins. These calculations specifically apply to the mixing time, where the gluten is being developed. (See Figures 3-20 and 3-21.)
The formula for calculating mixing time serves as a starting point to define proper mix times on specific equipment. The mixing times listed in Figure 3-21 are only guidelines, based on standard mixer speeds and full batch sizes. A variety of factors can affect mix time; this is why the texture of the dough and gluten development (window test) should always be the final guide. (See Figure 3-19, Step 3.)
Figure 3-20 Calculation of Mixing Time The following calculation can be used to determine the mixing time for the dough: Total revolutions required (as specified by mix method)/ Revolutions per minute (RPM) of the mixer = Total mixing time Revolutions per minute can vary with the brand of mixer, so before calculating mixing time, it is important to check the mixer's technical manual for its specific RPM. This information is also available from your equipment supplier.
FACTORS AFFECTING MIXING TIME
Mixing time can be adjusted to compensate for variables that can affect the development of the dough, including type and design of mixer, batch size, flour characteristics, dough hydration, and incorporation of additional ingredients.
Type and Design of Mixer
Motor speed, the shape of the hook, and mixer design can all affect the stretch-and-fold motion of the hook against the dough. A good example is to compare spiral mixers and oblique mixers. For an improved mix, a spiral mixer requires only 5 minutes of mixing in second speed, while an oblique mixer will require 121/y minutes. If different styles of mixers are used in a bakery, the same dough may require different mixing times, depending on the type of mixer used.
Batch size may be one of the most important factors to consider in mix time. Because mixers are generally designed to perform optimally at full capacity, smaller batches will generally mix faster than full batches because the dough comes in contact with the hook more often.
Figure 3-21 Example of Mixing Time Calculation The RPM of the mixer used in these examples will be as follows: Spiral mixer: 100 RPM in first speed 200 RPM in second speed Oblique mixer: 40 RPM in first speed 80 RPM in second speed Planetary mixer 107 RPM in first speed 198 RPM in second speed (20-qt Hobart): Planetary mixer 70 RPM in first speed 124 RPM in second speed (60-qt Hobart): Note: With respect to other planetary mixers, please refer to the technical manual to find out the exact RPM for various speeds. These values represent the average RPM for most of these styles of mixers. Short Mix Spiral mixer: 600/100 6 minutes in first speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 6 minutes in first speed for gluten development Oblique mixer: 600/40 15 minutes in first speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 15 minutes in first speed for gluten development Improved Mix Spiral mixer: 1000/200 5 minutes in second speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 5 minutes in second speed for gluten development Oblique mixer: 1000/80 12.5 minutes in second speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 12.5 minutes in second speed for gluten development Intensive Mix Spiral mixer: 1600/200 8 minutes in second speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 8 minutes in second speed for gluten development Oblique mixer: 1600/80 20 minutes in second speed Mixing time 4 to 5 minutes in first speed for ingredients will be: incorporation 20 minutes in second speed for gluten development
You should reduce mix time for partial batches, but there is no direct correlation between bowl size and mix time (a half batch won't mix in half the time, for example). Some experimentation will be necessary to determine the mixing time more precisely.
Strong flour may require longer mixing time because the gluten is less extensible and requires a longer time to reach the desired structure. Rye flour, for example, contains a lower quality and amount of protein, which makes it preferable to mix more in first speed and less in second speed. The gentler action of the hook in first speed will protect the fragile gluten structure of rye dough.
Lower hydration creates stiffer dough with less-extensible gluten that requires longer mixing time in comparison with medium-soft dough consistency.
Incorporation of Extra Ingredients
As mentioned earlier, if seeds, fruits, nuts, or other ingredients are added to the dough, they must be added after development has been completed. This incorporation should be done in first speed. Otherwise, these "chunky" ingredients can cut the gluten strands and slow down development.
COMPARISON OF THE MAIN MIXING TECHNIQUES
Figure 3-22 summarizes information about calculating mixing times and provides guidelines for each mixing technique's formulas and baking processes. Some explanations regarding different technical points are also included.
Figure 3-22 Comparison of Main Mixing Techniques Typical Formulation Improved Intensive Short Mix Mix Mix Flour 100% 100% 100% Water (1) 70% 67% 65% Fresh yeast (2) 0.5% 1.5% 2% Salt (3) 2% 2% 2% Baking Process Water temperature (4) 63[degrees]F 55[degrees]F (17[degrees]C) (13[degrees]C) Dough 76(3[degrees]C)F 76[degrees]F temperature (24(3[degrees]C)C) to (24[degrees]C) to 77(3[degrees]C)F 77[degrees]F (25(3[degrees]C)C) (25[degrees]C) First speed 3-4 minutes 3-4 minutes (100 RPM) (5) + 6 minutes Second speed 0 minutes 5 minutes (200 RPM) (6) First fermentation 3.5 hours 1.5 hours Punch and fold 3 0 or 1 Resting time 20-25 minutes 20-25 minutes Final proof (7) 45 minutes to 1 to 1.5 hours 1 hour Water temperature (4) 38[degrees]F (3[degrees]C) Dough 76[degrees]F temperature (24[degrees]C) to 77[degrees]F (25[degrees]C) First speed 3-4 minutes (100 RPM) (5) Second speed 8 minutes (200 RPM) (6) First fermentation 20 minutes Punch and fold 0 Resting time 20-25 minutes Final proof (7) 1.5 to 2 hours
COMPARISON OF MIXING PROCESSES AND EFFECTS ON THE FINAL PRODUCTS
Figure 3-23 summarizes the effects of each mixing method on the dough and the final product characteristics. Explanations regarding different characteristics are also provided.
Figure 3-23 Chart: Mixing Processes and Effects on Final Products Effect on Dough Short Mix Improved Mix Intensive Mix Consistency Fairly soft (1) Medium soft Stiff Strength Lacks strength Slightly lacking OK to strong in strength First fermentation Long Medium Short Machining Difficult (2) Possible Ideal Final proof Short (3) Medium Long Effect on Bread Short Mix Improved Mix Intensive Mix Volume Small Medium Big Color Creamy Less creamy (4) White Crumb Open, irregular Open, irregular Tight, regular Flavor Very complex Complex More bland Shelf life Longer Medium Shorter (1) A soft dough is needed in order to get enough gluten extensibility to be able to fold the dough efficiently. Punching and folding is necessary to develop the underdeveloped gluten structure. (2) The dough will be difficult to machine using a fully automated process, but semimechanized processes are still possible using equipment such as hydraulic dough dividers and regular baguette molders. (3) Less C[O.sub.2] can be retained in the dough due to the more underdeveloped gluten structure. (4) Though less creamy than breads produced with the short mix, the crumb color is still definitely acceptable.
DEVELOPING YOUR OWN PROCESS
Mixing and fermentation can be "balanced" to achieve desired bread characteristics and production parameters. The right way to mix depends mainly on the attributes the baker wishes to achieve in the dough, and each technique has its own benefits and tradeoffs.
Although only three main mixing techniques are described in this chapter, once the baker can control and understand each of them, it can be said that there are as many ways to mix as there are ways to make bread. The baker must, however, keep in mind that mixing and fermentation work together, and if mixing is changed, fermentation time may have to be changed as well.
WHICH METHOD TO USE?
Some principles also apply to any type of bread produced in a bakery, including whole wheat and sourdough, which is why it is important to know how different mix methods will affect the final product before a technique is chosen.
Once the baker understands the differences between each method and their effects on the outcome of the final product, the method that works best in the individual baking environment can be devised. Begin this process by answering the following questions:
* What characteristics do I want my bread to have?
* What schedule/time issues do I have to work within?
* What equipment issues are involved (batch size, type of mixer, and the like)?
The answers will determine which mixing technique will provide the qualities most important to the particular product being made.
Sometimes, some adjustments to the method might be necessary. For example, when making pan bread, the required characteristics of the final product are the tight and even crumb provided by intensive mixing. Unfortunately, as has been discussed, an intensive mix will dull flavor. In order to counteract this, the baker can involve a preferment in the formula rather than resorting to short or improved mixing, which will produce a more irregular crumb.
It is important to keep in mind that when mixing methods are altered to achieve one characteristic, all the other characteristics that go with that method will be there as well. For example, dough cannot be developed to achieve a tight crumb and allowed to ferment for a long time, or it will be overdeveloped and lose its extensibility. The end result will be very difficult to work with.
In the same way, choosing a method to extend fermentation will result in all of its effects, including gassier dough that's harder to work with.
Understanding these important interconnections gives bakers more flexibility to balance the product attributes they want with the methods that best fit their production schedules.
MIXING AND TRAINING
In a large production environment, the baker in charge of mixing should see all the final products that were the result of his or her mixing shift. This can be a great learning experience, for, as we said earlier, a number of bread characteristics such as volume, crumb, and cut openings can be positively or negatively affected by the mixing time.
Standardizing the mixing procedure in large bakeries is also very important to guarantee a good consistency in production, regardless of which baker or which shifts mixed the dough.
There are several critical points during the mixing process where it is possible for mistakes to happen. However, through regimented and careful execution of each task, results should be fairly consistent and good.
If a dough is not scaled properly, the ratio of ingredients will be off, and the intended result of the formula will be difficult, if not impossible, to achieve. The results may be noticeable within the first few minutes, as in the case of water that is improperly scaled. Problems with salt or yeast, on the other hand, may not be noticeable until the first fermentation or after the baking process is complete. You can ensure that all ingredients are properly scaled by double-checking measurements against the printed formula.
Even though all ingredients may have been properly scaled, they may not all make it into the dough. The implications of this depend on the missing ingredient, the most common of which include yeast, salt, sugar, and butter. On the other hand, it is hard to imagine someone forgetting the olives for olive bread.
How to remedy the situation will depend on what was forgotten and how much time has passed. If salt or yeast has been forgotten and the dough has just finished mixing, the salt or yeast should be dissolved in a small quantity of water and added to the dough in first speed. The same technique can be used for yeast that has been forgotten for up to 1 hour after mixing, if no preferment is being used. A missed addition of salt is trickier because the dough has been through a process of fermentation. Mixing the dough after this will have a negative effect on its rheology.
Under- or overmixing the dough will change the physical characteristics of both the dough and the bread. This may affect the first fermentation time, which in turn can affect the rest of the baking process. Please refer to the charts in this chapter for specific results linked to under- or overdeveloping dough.
Mixing is not a very complicated step, but it does require a great deal of care and accuracy. It is fairly simple to understand that if mixing is done carefully, all of the steps after it will be easy. But if the dough is not right after mixing, the baker will have to know how to adjust and troubleshoot the baking process in order to produce a good-quality product. This can quickly turn a smooth production day into a difficult one. The incorporation of ingredients must be done in the proper order, dough should be developed using the correct mixing techniques, and the ideal dough temperature should be achieved in order to get the desired final product characteristics. if
* Bulk fermentation
* Carotenoid pigments
* Desired dough temperature (DDT)
* Dough development
* Dough rheology
* Final proof
* First fermentation
* Floor time
* Gluten development
* Improved mix
* Intensive mix
* Intermediate proof
* Oven loading
* Professor Raymond Calvel
* Short mix
* Traditional method
1. What are the three primary mixing methods and what effect does each one have on a final loaf of bread?
2. Why is it important to know and control the water temperature when mixing dough?
3. True or False: If mixing a baguette to an improved mix and the final temperature is 72[degrees]F (22[degrees]C), it is recommended to continue mixing until the desired dough temperature is reached.
4. What is oxidation of the dough? How can it be controlled?
5. What is double hydration and when and how is it used?
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|Title Annotation:||PART 2 BREAD|
|Publication:||Advanced Bread and Pastry|
|Date:||Jan 1, 2009|
|Previous Article:||Chapter 2 Food safety and sanitation in the bakery.|
|Next Article:||Chapter 4 Fermentation.|