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Encyclopizza®
is researched, written, and complied by John Correll.
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CONTENTS
The
Ready-to-Use Option
• Using a Partial mix
• Advantages and Drawbacks
Baker's
Percents
Types
of Ingredients
Flour
• Role in Baking
• Wheat
• Species and
Varieties
• Wheat Classification
• Color of Wheat
•
Flour Protein
• Amylase Content, Wheat Sprouting, and Gummy Layer
• Kernel Structure
• Wheat Grades
• The Milling Process
• Flour Grades
• Flour Treatment and Additives
•
Flour Composition and Reactions
• Properties of Quality Pizza Flour
• Flour Testing Methods
• Gluten Ball Test
• Baking
Test
• Flour Purchasing and Storage
• Three Types of Bakery
Flour
• Flour for Pizza Crust
• Bleached vs. Unbleached
• The Look and Feel of Pizza Flour
• Type and Grade
•
Packaging Sizes
• Product Consistency
• Brands
•
Technical Assistance
• Storage
• Supplemental Flours &
Meals
• Types
• Amount
• Dough Changes
Water
• Amount and Baker's Percent
• Hardness
•
pH
Yeast
• Fermentation
• Role of Yeast
• Factors Affecting Amount
of Rise
• Conditions Affecting Fermentation Rate
• Rehydration
• Varieties of Yeast
• Compressed Yeast
• Preparation
and Usage
• Storage
• Advantages & Drawbacks
•
Crumbled Yeast
• Cream Yeast
• REGULAR Active Dry Yeast
• Rehydration and Usage
• Storage
• Advantages &
Drawbacks
• INSTANT Dry Yeast
• Dry mixing, Rehydration, and
Usage
• Storage
• Advantages & Drawbacks
• PROTECTED
Dry Yeast
• Summary Recommendations
Chemical
Leaveners
Salt
Sugar
• Effects of Sugar
• Types and Amount of Sugar
Oil & Shortening
• Effects of Oil & Shortening
• Types and Amount of Oil &
Shortening
• A Word on Olive Oil
• Amount
• Health
Considerations
• Saturated vs. Unsaturated
• Cholesterol Content
• Storage
Non-fat Dry
Milk
• Effects of Non-fat Dry Milk
• Amount
• Whey and Other Diary Products
• Storage
Eggs
Flavorings & Colorings
•
Flavor Variations
• Color Variations
Dough
Additives
• How to Start
• Types of Additives
• Nutritional Enhancements
• Vital Wheat Gluten
•
Whey & Milk Replacers
• Fermentation Enhancers - Yeast Foods and
Water Conditioners
• Fermentation Enhancers - Enzymes (Malt)
•
Gluten Relaxers - Protease Enzymes & Reducing Agents
• Gluten Strengtheners
- Oxidizing Agents & Dough Strengtheners
• Surfactants
•
Gums
• Mold Inhibitors
• Concluding Note
NOTE:
Visit the Encyclopizza
home page for the complete Table of Contents, including pizza dough/crust/sauce
recipes.
ONE of the most complex aspects of pizza is dough. It offers many ways for something to go wrong. However, with knowledge and proper procedure, mistakes can be minimized and consistent top quality crust can be produced. This chapter provides an understanding of the ingredients used in making dough.
Lengths, weights, temperatures, and volume measurements are given in inches, pounds and ounces, degrees Fahrenheit, and quarts and cups (U.S. version). The following abbreviations are used: lb = pounds, oz = ounces, F = Fahrenheit, and qt = quarts. For conversion to other measurement systems, refer to the chapter on Measurements and Conversions.
An alternative to scaling individual ingredients is the prepared mix, also called
pre-mix and pre-blend. There are two kinds: a complete mix, which contains
all the dry ingredients for dough, including flour (however, some exclude yeast),
and a partial mix, which contains all dry ingredients except for flour
(some also exclude yeast).
Many companies sell generic mixes. In addition they will blend to specification for large buyers. Finally, it’s possible for a pizzeria to make its own mix. Once a week, scale the salt, sugar, etc. needed for a week’s worth of dough. Mix it uniformly. Put it into a plastic bag, seal it tight, and store it in a cool store room or a walk-in cooler. The process can save labor and reduce the chance of scaling error during dough-mixing.
Some partial mixes include yeast, others don’t. Instant, regular active dry, and protected active dry yeast can be used. Instant dry yeast can be mixed without rehydration. However, regular and protected active dry (ADY and PADY) yeast must be rehydrated before mixing. To do that the entire mix is put into water, which results in the yeast being rehydrated in salty water. If it’s a high concentration of salt it can inhibit fermentation. For this reason it’s important to use plenty of water, or at least ten times the weight of mix. To avoid this potential problem some people exclude yeast from the mix and, instead, add it separately.
PADY is sometimes preferred over ADY or instant yeast because it’s protected from oxygen and moisture. With ADY and instant, the mix must be properly packaged and/or stored cold to prevent deterioration of the yeast.
The main advantage of a mix is that it provides consistency by reducing the chance of scaling error. Also, for a company wanting to keep its recipe secret, a custom-blended mix offers a way to do that.
The main drawback of a mix is increased food cost. Of the two, complete mixes are the most expensive. A partial mix is less so. For more discussion see the chapter on the Ready-to-use Option.
For convenience, bakers refer to ingredient amounts in a dough formula as a percentage
of total flour weight. That means, regardless of how much flour a recipe calls
for, the flour amount is always considered to be 100 percent and every other
ingredient is referred to as a percentage thereof. For example, if a formula calls
for 25 lb flour and 15 lb water, they would say that the formula consisted of
60 percent water (15 ÷ 25 = .60 or 60 percent). They call this a baker’s percent.
To further illustrate, if a baker said “lower water by 5 percent,” this would
mean that the water portion should be reduced 5 percent of the weight of the flour
portion called for by the recipe.
Throughout this chapter and other chapters on dough, whenever we mention percentages we’re referring to baker’s percents. So keep in mind that these percents relate to a percent of the total flour weight in the dough formula, not to a percent of total dough weight.
Typical pizza crust is made from yeast dough. In its basic form a yeast dough
consists of flour, water, yeast, and salt—the basic four ingredients of bread.
A fine pizza crust can be created with only those ingredients. However, to impart
special qualities to dough and crust some recipes also contain chemical leavening,
sugar, shortening (oil), egg, milk, flavoring, and/or dough additives. So, in
creating a pizza dough we have ten categories of ingredients to consider.
• Flour
• Water
• Yeast & Other Leaveners
• Salt
• Sugar
• Shortening or Oil
• Non-fat Dry Milk
• Egg
• Flavoring & Coloring
• Dough Additive
Generally defined, flour is finely ground, starchy material produced from
milling the seeds or fruit of various plants, most notably cereals. There are
many types of flour, including wheat, corn, oat, rice, rye, buckwheat, barley,
and triticale flour. There’s also soybean, almond, tapioca, peanut, cottonseed,
and potato flour.
By far, the main flour used in baking comes from wheat. In fact it’s so common that the federal government says the word “flour,” when used by itself, refers to the material produced from grinding and sifting wheat.
During the milling process the brownish-colored bran and the germ portion of the grain are separated from the white, starchy inner portion, called endosperm. It’s the finely ground endosperm that we know as flour. Other terms for it are wheat flour and white flour. So when we speak of flour we’re referring to that product that is the finely ground endosperm of wheat.
Terminology Note
The term “wheat flour” should not be confused with “whole wheat flour.” Wheat flour is white flour. It contains only the white endosperm portion of the kernel, and does not contain significant amounts of germ and bran. Whole wheat flour, on the other hand, contains the entire kernel, including the germ and bran. So, when a label lists “wheat flour” it’s actually referring to white flour, not whole wheat flour. This is something that many consumers don’t realize.
Flour and water are the indispensable ingredients in baked goods. When combined, the flour absorbs the water, making dough (or batter). Without flour, baking and pizza-making as we know it wouldn’t exist.
The flour-water combination binds or holds other dough ingredients. In addition, flour contributes special flavor and nutrients. Finally, because of it’s unique protein, flour allows dough to rise during fermentation and to retain its shape and volume after baking.
For a full understanding of pizza flour, how it works and why it can vary, it helps to have a basic knowledge of wheat. This section describes those aspects of wheat and wheat production that might be of interest to a buyer, quality assurance director, or manager.
Worldwide, there are fourteen species of wheat, all beginning with the name Triticum. However, over 90 percent of wheat production comes from three species: Triticum aestivum (also called Triticum vulgare), or common wheat; Triticum durum, or durum wheat; and Triticum compactum, or club wheat.
Common wheat is by far the most important, comprising over 90 percent of wheat production in the United States. Common wheat is used mainly in baking. Durum wheat, sometimes called macaroni wheat, is used for making pasta. And club wheat, which yields a very soft flour—low in protein content—is used for items needing a crumbly texture, such as crackers. Pizza flour comes from common wheat, so the rest of this discussion focuses on that.
To achieve better wheat, scientists are constantly making hybrid varieties. Through hybrids they create wheat with special characteristics such as greater yield, disease and insect resistance, shorter growing season, different color, kernel hardness, better milling and baking qualities, and shorter stem to resist flattening by wind. In the U.S. alone there are over 100 varieties of common wheat. Different wheats produce markedly different flours. Other factors affecting wheat and flour characteristics are weather conditions and the milling process.
To promote product consistency, the USDA (U.S. Department of Agriculture) groups the varieties of wheat into classes, or strains. The classes are based on three factors: (1) The texture of the ripened kernel (hard or soft), (2) the color of the kernel (red, amber, or white), and (3) the season when the wheat begins growing (winter or spring). As such, common wheats are grouped into the following five classes:
• Hard red winter wheats (HRW)
• Soft red winter wheats (SRW)
• Hard red spring wheats (HRS)
• Hard white wheats (winter and spring)
• Soft white wheats (winter and spring)
Two other wheat classes are durum and red durum. Durum, which is amber colored, is used for making pasta; red durum is used for livestock feed. In each of the above classes there are two to four sub-classes. When two or more classes are blended together during milling it’s called a “mixed wheat.” Approximately 45 percent of wheat is HRW, 21 percent is SRW, 18 percent is HRS, 11 percent is hard and soft white wheat, and 5 percent is durum.
Winter wheats are planted in the fall in regions with mild, dry winters, most notably in those states across the middle of the U.S. In fall the wheat takes root and leaves and shoots emerge. During winter it enters a dormant or vegetative stage. In spring it resumes growing and, finally, is harvested in June or July. Hard red winter wheats mainly come from Kansas, Nebraska, Oklahoma, Texas, and Colorado. Soft red winter varieties are mainly grown in Ohio, Indiana, Missouri, Illinois, and Pennsylvania.
Spring wheats are planted in early spring in regions with harsh winters that would kill a winter wheat. They are harvested in late summer. Minnesota, North and South Dakota, and Montana, as well as Canada, are main producers of hard red spring wheat.
White wheat—which includes hard and soft varieties—is produced mainly in the Pacific Coast states, New York, Michigan, and Canada.
True winter wheat will not yield a crop if planted in spring, and spring wheat will not survive the harsh winter if planted in high northern states in the fall.
The color of each wheat strain derives from the color of the outer layer known as the bran layer. And the color of the bran derives from the amount of tannin it contains—the more tannin, the darker the color. So the three red wheat strains contain a higher amount of tannin and the two white wheat strains contain a lesser amount. In addition to having a reddish-brown color, tannin also imparts a slightly bitter flavor—so the more tannin, the more-bitter the flavor of the bran layer.
From a baking standpoint, the most important property of flour is its protein. When flour is mixed with water the protein forms gluten—a substance which gives firmness to baked goods. Generally speaking, the more protein in the flour, the more elastic the dough will be and the firmer the final baked product will be. In addition the quality of the protein plays a role as well. A flour with a higher protein content but of low quality may not perform as well as a flour with slightly less protein but of higher quality. Yeast breads such as pizza crust are typically made from flour with moderate-to-high protein content (11 to 14.5 percent). And cakes, cookies, and quick breads (i.e., muffins, biscuits, pancakes, etc.) are made with low protein flour. Pastries are usually made with a flour containing a low-to-moderate amount of protein.
Generally speaking, protein content is related to the hardness of the wheat kernel, such that hard wheats produce flour with moderate-to-high protein content and soft wheats produce flour with low protein content. Most yeast breads, including pizza crust, are best when made from higher protein flour (at least 11 percent or more protein). So, flour for pizza crust typically comes from hard red spring and hard red winter wheats and, to a lesser extent, from hard white wheats. Hard red spring wheat produces the highest protein level (13 to 14.5 percent) and the other two produce a moderate-to-high level (10 to 13 percent).
In addition to the growing season and the variety of wheat, environmental factors such as weather greatly affect wheat’s protein content and baking performance. In fact, some experts believe that environment plays a larger role in flour quality than the variety of wheat. So flour produced from a certain variety of wheat from the same region can vary from year to year. For example, the cooler the weather during growing season, the lower the protein content of wheat. And the greater the rainfall, the lower the protein content, as well. To overcome seasonal variations and, thereby, achieve consistent performance characteristics, millers blend wheats of different varieties and from different sources. They blend various flours, as well.
Another factor that can affect the baking performance of pizza flour is wheat sprouting, or germination. Normally when wheat reaches maturity it goes into a state of dormancy, or biological inactivity. If wheat is harvested during dry conditions the dormancy continues during storage. However, if there’s heavy rain just before harvest the wheat’s moisture content will rise markedly. When the moisture content exceeds a certain level, sprouting—sometimes called germination—occurs in the field or during storage. The harmful effect of sprouting is an increase of certain enzymes within the wheat, most notably the enzyme alpha-amylase—which increases as much as 5000 times over the amount found in dormant wheat. (An older term for amylase enzymes is “diastase.”)
To understand the problem of too much alpha-amylase, we must understand how flour performs with normal amounts of enzyme. Flour is composed mainly of microscopic starch granules. The granules are composed of starch molecules. Chemically speaking, a starch molecule is made of thousands of carbon atoms connected together—resulting in a very long molecule. During milling, a percentage of the granules are damaged, or broken open, which exposes the long starch molecules to attack by amylase enzymes. In dough, two amylase enzymes—alpha-amylase and beta-amylase—attack the exposed molecules. Alpha-amylase breaks down the molecules into shorter mid-length molecules, called dextrins. This continues up to and including while the pizza is baking. Beta-amylase attacks the dextrin molecules and converts them to a sugar called maltose. This process of breaking down starch molecules into dextrin and maltose is known as diastatic or amylolytic activity. Finally, yeast digests the sugar—a process called fermentation—which results in CO2 gas and rising of the dough. Without the combined action of alpha- and beta-amylase there would be very little maltose for the yeast to digest and, as a result, the pizza crust would be flat and poorly risen.
However when there’s too much alpha-amylase, as a result of sprouting—or even possibly from adding too much diastatic malt product—an enzyme imbalance occurs. The alpha-amylase produces more dextrin than can be reduced to maltose by the beta-amylase. The sad result of too much dextrin is a sticky, gummy crumb in the finished bread, with a tendency for the bread structure to collapse. In extreme cases all the cell walls collapse, resulting in a solid sheet of unaerated starch gum known as gummy layer, also sometimes called gel layer. In pizza this condition is seen as a grayish, translucent gummy layer just under the sauce. In mild cases this layer is thin, which can be seen by tearing the crust in half and examining the side. In extreme cases the entire crust is little more than a sheet of dense, unrisen gum. (Gummy layer should not be confused with doughy layer which is uncooked raw dough, or dough that hasn’t received enough heat during baking.)
Normally, sprouting is not a major problem in the United States (although it’s more common in Europe). If, however, a pizzeria receives flour made from an overly high amount of sprouted wheat, the dough will form a gummy crumb or even collapse during baking. And no amount of extra baking—either higher temperature or longer time—will fix the problem.
The part of the wheat plant that’s used for making flour is the reproductive component known as the kernel. It consists of three parts: bran, germ, and endosperm. The bran is the tough, protective, outer covering. The germ or embryo is a small portion at the base of the kernel that develops into a new plant on germination. The endosperm, or starchy inner portion, constitutes the main part of the kernel, and provides a reservoir of food for the growing seedling. About 83 percent of the kernel is endosperm, 15 percent is bran, and 2 percent is germ. From a baking standpoint, the endosperm is the most important. To see a wheat kernel cross-section, click here.
White flour, also called wheat flour, consists of finely ground endosperm. Whole wheat flour, on the other hand, consists of the finely ground whole kernel, or all three parts.
The bran consists mainly of cellulose fiber which can aid digestion. It also holds a large portion of the many vitamins found in wheat. Depending on the variety of wheat, the color of the bran might be red, amber (yellow), or white. In strains of red wheat, it’s the reddish-brown bran that gives whole wheat flour it’s tan color.
Compared to the other two parts, the germ is high in oil. During prolonged storage, especially at high temperature and humidity, oil will oxidize, or turn rancid, which can give flour a bad odor and flavor. To prevent this occurrence, and also to improve the flour’s baking quality, the germ is removed during the milling process. Many vegetable oils, such as corn oil, are produced by separating the germ from the grain and then squeezing out the oil.
The endosperm consists of over 30,000 starch-containing cells. Around each starch cell is a cellulose wall. Inside each cell are starch granules, or microscopic grains of starch, lodged in a protein matrix or filling. Starch granules come in three sizes—small, medium, and large—with most of them being either small or large. The percentage of each size varies with the different varieties of wheat. Generally, the lower the percentage of small starch granules, the better the baking performance of the flour.
The endosperm of hard wheats is harder than that of soft wheats (hence the respective names). Hard wheat endosperm tends to be translucent, whereas that of soft wheat is more opaque. Hard wheat endosperm produces a gritty, creamy-colored flour that is somewhat free-flowing. Soft wheat endosperm yields a softer, whiter flour that tends to clump.
For classification, the U.S. Dept. of Agriculture divides each class of wheat into two to four sub-classes. (We listed the classes of common wheat earlier, but not the sub-classes.) To standardize quality within each sub-class there’s a grading system. The system consists of five grades, 1 to 5, plus a sample grade. Grade 1 is the best; sample is the worst.
In grading a certain sub-class the inspector considers the percent of the following elements found in wheat: Damaged kernels, shrunken and broken kernels, foreign matter, and other classes of wheat mixed in. The less of each item, the better. They also consider the weight per bushel—the heavier, the better. Because of the bad affect of high moisture (which causes sprouting, among other things), the system specifies a maximum moisture limit in the wheat. Finally, if the wheat contains obnoxious odors (i.e., garlicky, moldy, smutty) or excessive weevil numbers, it is excluded from use for humans and put into the sample grade.
To make flour, wheat undergoes a process of cleaning, grinding, and sifting—called milling. The purpose of milling is (1) to remove the germ and bran from the endosperm and (2) to obtain the maximum amount of endosperm without damage to the starch granules. In simplified form, it goes like this.
FIRST, the milling company selects varieties of wheat for milling. It might create a blend to produce a flour of certain characteristics.
SECOND, the wheat is cleaned to remove foreign matter such as weeds, dirt, insects, stones, metal, chaff, and undesired cereals. To accomplish this the grain moves through various devices such as vibrating screens, forced air aspirator, disc separator, scourer, magnetic separator, and washer-stone remover. It might also go through an entoleter, a machine which removes unsound kernels.
THIRD, the wheat is conditioned, or tempered, by soaking in water and then storing for 8 to 24 hours. For proper milling the wheat should develop about 16 percent moisture. Tempering makes the bran layer tougher and, thereby, easier to separate from the endosperm. Also, with proper moisture content the endosperm softens and breaks apart more readily.
FOURTH, the wheat goes through an entoleter that removes unsound kernels.
FIFTH, the cleaned wheat is cracked between rollers and sifted. The process is repeated many times until as much endosperm as possible is freed from the bran and germ. Typically that amounts to 72 percent of the wheat. Each rolling and sifting is called a break, and the flour that results from each break is called a stream.
To begin the process, the wheat is cracked between a pair of corrugated rollers, called break rolls, that rotate inward toward each other at different speeds. The cracked wheat is then separated into three parts by sifting, also called bolting, which consists of a stack of gyrating screens of varying fineness. The coarse particles, which contain bran and endosperm combined, are caught by the top screen. Medium-size particles of freed endosperm, called middlings or farina, are caught by the middle screens. And the finest endosperm particles, which pass through the bottom screen, are flour.
The coarse particles (bran and endosperm combined) move on to another set of break rolls. The stock is again sifted into three parts—coarse particles, middlings, and flour. There are five or six successive break rolls in all. After each one, the coarse particles are sent on to another break roll and the middlings move to a series of air purifiers and reducing rolls. After the last break roll only bran is left, which is used for livestock feed.
Middlings from each break go to an air purifier that removes loose bran particles and sifts the middlings into various sizes. The middlings then move on to a series of smooth rollers, called reducing rolls. The first reducing roll flattens the freed germ particles, which are then removed in another air purifier. Stock from the reducing roll is again sifted, with the finest particles falling off as flour and the larger ones proceeding through successive air purifiers and further reducing rolls. The process of sifting-purifying-rolling is repeated many times until all usable endosperm has been reduced to flour, and all that’s left is a residue of finely ground bran, germ, and flour, known as red dog, which is used for livestock feed.
For good baking, endosperm particles (i.e., flour) must be ground to proper size. Particles that are too large fail to absorb enough moisture. Particles that are too small absorb too much. Proper particle size produces baked goods with uniform cell structure, good oven spring, and maximum volume.
SIXTH, bleaching and maturing agents, along with malted product, are applied to the flour—and possibly it’s enriched—then it’s packed and stored for shipment. When packed for large bakeries it’s put into 3,000 pound containers, 45,000 pound capacity bulk trucks, or 100,000 pound capacity railroad cars. For neighborhood bakeries and pizzerias it’s packed in 25, 50, and 100 pound bags.
Flour
that isn’t chemically treated must usually be “naturally aged” by storing for
8 to 10 weeks. For a diagram of the flour milling process, click
here.
An interesting fact of milling is that the streams of flour produced from the various rolls or breaks are not the same. The early streams in the milling process—known as first stream, second stream, and so forth—yield a purer flour that’s lower in bran and germ content and whiter in color than the flour coming from later streams. Therefore, flour from earlier streams has better baking performance and, consequently, is more desirable than flour from later streams.
With that in mind, flour is graded according to when it was produced during milling. The best or purest flour is from the early streams—and it’s called patent flour. By contrast, the flour that comes after patent flour is less pure—and it’s called clear flour. The last 5 percent of flour produced is called low grade clear, and it’s of such poor quality that it’s separated out and not used for baking.
There are various types of patent and clear flour. Since the classifying is done by the mill, the standards aren’t uniform industry-wide. However here’s how it typically breaks down.
FANCY PATENT. Generally speaking, flour that’s derived from the first 40 to 60 percent of flour yield is called fancy patent flour—and the remaining flour is called fancy clear.
SHORT PATENT. Flour that consists of the first 60 to 80 percent of flour yield is called short patent flour—and the remaining flour is called first clear.
MEDIUM PATENT. Flour consisting of the first 90 percent of the yield is called medium patent, and also sometimes called bakers or standard flour—and the remainder is called second clear.
LONG PATENT. Flour from the first 95 percent is called long patent and sometimes family flour—and the remainder is low grade clear.
STRAIGHT. When all the flour streams are combined it’s called straight or 100 percent flour.
As a rule, the later the stream of flour, the higher the bran and germ content, and the darker the color. Low grade clear, for example, is so high in bran and germ content, and so dark in color, it isn’t used for baking.
Hard wheat mills, which produce high-gluten pizza flour, generally classify the first 75 to 80 percent of the yield as short patent, and the remainder is divided into two parts, first and second clear, with first clear being the higher quality.
Another interesting fact of milling is that flour from the later streams contains more protein than that from the earlier streams. In other words, from the same batch of wheat, clear flour has a higher protein content than patent flour. For that reason a high protein first clear flour is often used for mixing with a lower protein or no-protein flour—such as rye flour—to make specialty breads. In this case it doesn’t matter that the clear flour is lacking pure white color.
Flour can be enhanced a number of ways, as discussed here.
CHEMICAL OXIDANTS OR FLOUR IMPROVERS. To perform properly in baking, flour must first undergo oxidation—a process that changes its protein structure for better baking results. Without proper oxidation the bread or pizza crust turns out under-risen and with a coarse texture and overly large cell structure.
Originally oxidation was accomplished by storing flour under controlled conditions for 8 to 10 weeks, and turning it several times to expose the entire stock to air—a process known as aging. It was cumbersome and costly, and also increased the chance of insect infestation. So millers developed ways to circumvent the aging process through chemical treatment, sometimes called chemical aging. Although the methods are different, natural and chemical aging produce the same result: Oxidation of the flour’s protein.
The group of chemical additives used for oxidizing flour is known as flour improvers, and sometimes also called maturing agents. Traditionally the main flour improver has been potassium bromate. Flour that contains it is referred to as “bromated flour.” However some states have begun viewing potassium bromate as a potentially harmful chemical and, so, have required that it be labeled as such on food products. As a result, millers and bakers have started replacing potassium bromate with alternate flour improvers, most notably ascorbic acid—commonly known as vitamin C. Functionally speaking the main difference between potassium bromate and ascorbic acid is that potassium bromate is a slow-acting oxidzer whereas ascorbic acid is very fast acting. In the end they produce similar results on the dough.
Other flour improvers include potassium iodate, calcium bromate, calcium iodate, calcium peroxide, and azodicarbonamide (ADA, for short). Although they all oxidize flour protein, they vary in the speed at which they do it and also in the dough stage at which it occurs. For example, with potassium bromate and calcium bromate the oxidation occurs during the initial phase of baking, or in the oven. But with the others, including ascorbic acid, it occurs earlier during the mixing and fermentation stages. Oftentimes two or more improvers are blended together and added to flour in combination.
Flour that’s unoxidized, or unaged, is referred to as “green” flour.
BLEACHING. Years ago, because white flour was more expensive than whole wheat it was viewed as better. To meet consumer demand, millers invented bleaching as a technique for creating the whitest possible flour. Bleaching, or flour whitening, is accomplished by adding chemicals that oxidize the natural yellow pigments of flour.
The two most commonly used bleaching agents are benzoyl peroxide and chlorine. Benzoyl peroxide is added to both hard and soft wheat flours. It performs no other function than whitening, and does not affect baking properties. Chlorine, on the other hand, is added mainly to soft wheat flour—the type used for cakes. In addition to whitening, chlorine also oxidizes the protein and starch components of flour, resulting in a lighter, airier cake crumb.
For a long time bakers have used the word “bleaching” as a reference to both whitening and maturing when, technically speaking, bleaching only means whitening.
Although most bread flour is bleached, in fact it doesn’t have to be. Unbleached flour produces just as good a pizza crust as bleached. The only difference is the color of the crumb. Unbleached flour will have a faintly yellowish or more creamy-colored crumb—something which some pizzerias might even find desirable.
ENZYME ENHANCEMENT. For good fermentation, flour for yeast breads must contain a certain amount of alpha-amylase enzyme (as previously discussed). However, the amount of enzyme in wheat crops varies from year to year. So to overcome an enzyme deficiency, millers blend in a small amount of additional alpha-amylase. Traditionally this has been added in the form of malted wheat or barley flour that has been specially processed to make it high in enzyme. However, some millers add alpha-amylase through a fungal enzyme. With the right amount of alpha-amylase the end-result is proper fermentation and rise in the dough. (Too much, however, will result in a sticky, gummy crumb—the same as occurs from sprouted wheat.) When malted flour or fungal enzyme is added it’s listed in the ingredients.
ENRICHMENT. Unfortunately some of wheat’s nutrients are lost in removing the bran and germ. To compensate, many states and countries require that flour be enriched. It’s accomplished when millers (or bakeries) add thiamine, riboflavin, niacin, iron, and sometimes calcium and vitamin D. The items are listed on the label. Such flour is called enriched. Decades ago, enrichment helped eradicate dreaded diseases like beri beri and pellagra, as well as iron deficiency anemia. Today we take enrichment for granted.
LEAVENING AGENTS. Some flours contain chemical leavening agents. When baking powder has been added it’s called self-rising flour. Flour that contains monocalcium phosphate is called phosphated flour. These flours are used mainly for biscuits, corn bread, muffins, and the like.
INSTANTIZED FLOUR. Flour that has been specially processed or sifted to make it free pouring and instantly dispersible in cold liquid is called instantized, instant blending, or quick mixing flour. Unlike regular flour, it is relatively dust-free. It’s produced for large commercial bakeries that want a free-flowing mixture. It’s not commonly used by pizzerias, although it might be handy for dough slapping or bench dusting—or any other actions that tend to create flour dust.
Generally speaking, hard wheat flour consists of 75 percent starch, 12 percent protein, 12 percent water, and 1 percent fat. The important components are starch and protein. This section describes the main characteristics of wheat starch and protein.
ROLE OF STARCH. Starch plays a key role in pizza crust. First, it provides body to the product. Second, it’s responsible for the crumb texture. Third, as a result of amylase action on ruptured starch granules, it provides sugar for yeast fermentation. Fourth, by diluting the gluten it creates a crust of desirable consistency. Fifth, as the starch gelatinizes during baking, it draws water from the gluten contained in the cell walls. This, in turn, causes the gluten to become firm and also causes small holes to develop in the cell walls. The holes allow air to flow freely throughout the crust, which keeps the freshly-baked crust from forming bubbles during baking and from collapsing during cooling.
GELATINIZATION. When starch comes into contact with hot water (above 140 degrees F) it absorbs the water by trapping it between long starch molecules. The process is called gelatinization. During gelatinization the starch granules open up and expose starch molecules to amylase attack. From 140 degrees to 175 degrees F, rapid starch decomposition occurs from alpha-amylase. Above that temperature the amylase is deactivated. When extremely high amylase levels are present in dough, due to wheat sprouting or possibly from adding too much malted flour, extensive flour decomposition occurs during baking. This produces excessive dextrin, which fosters a sticky, gummy crumb.
RETROGRADATION OR STALING. In freshly baked bread or pizza crust, starch molecules exist in coils which trap water molecules. The trapped water produces the wonderful soft, moist texture of fresh-baked product. As the bread ages, the molecules begin to straighten out and the water escapes. The process is called staling or, in scientific terms, starch retrogradation. Eventually the straightened molecules line up side-by-side, which results in the hard texture of completely stale bread. To slow down retrogradation some bakers add emulsifiers, such as monoglycerides and diglycerides, which combine with starch molecules and inhibit the straightening or retrogradation process.
Bread remains fresh below freezing temperature and above 140 degrees F. However, it stales rapidly in a refrigerator. So if it can be avoided, it should not be stored there. Bread made of lower protein flour stales more rapidly than that made of higher protein.
ROLE OF GLUTEN. The unique component of wheat flour is protein. Two groups are most important: gliadins and glutenins. When mixed with water they form gluten, a substance that imparts elasticity to dough and firmness to the baked product. Gluten consists of very long, coiled protein molecules which provide springiness to dough and yeast bread.
Gluten plays a vital role in the structure of pizza crust. The process works like this. During mixing, minute air cells form in the dough. As the dough undergoes fermentation, CO2 gas pushes into the cells. Thanks to the elastic gluten, the cell walls expand with the gas rather than break. Without gluten, the cells walls would rupture and the gas would dissipate from the dough, causing the baked product to be dense and flat. So gluten provides an elastic matrix in which air cells can expand without breaking, which makes for nicely risen pizza crust.
FACTORS AFFECTING GLUTEN STRENGTH. The strength (or elasticity) of gluten affects the rise and texture of pizza crust. In addition to flour quality, a number of factors affect gluten strength—notably, amount of water, extent of mixing, amount of fermentation, presence of protease enzymes in flour, and the presence of other ingredients such as dough conditioners.
For full gluten development, dough needs 50 to 60 percent water (compared to flour weight). Too little water makes for under-hydrated gluten, which results in a dry, stiff dough with little stretch. Some thin-crust pizzas are made from dough with less than 50 percent water in order to produce a flat, crackery crust. Too much water makes for over-hydrated gluten, which results in a wet, slack dough with no elasticity or spring-back if pulled.
Mixing and kneading also develops gluten’s elasticity. If under-mixed, the dough can lack elasticity. If over-mixed, it can become sticky and too extensible. Properly mixed with 50 to 60 percent water, a yeast dough is smooth with a satiny appearance and is capable of being stretched into a paper-thin sheet.
During fermentation, gluten develops further. Interestingly, a stiff dough (40 to 50 percent water to flour weight) if allowed extensive fermentation—such as would occur in 24 hours in a tub in a warm spot in a pizza store—will soften considerably and improve in gluten elasticity.
Ingredients that tend to strengthen gluten are salt, milk, and acids (ex., vinegar, sour milk). Ingredients that tend to weaken it are fat, sugar, alkalis (ex., baking soda), and added starch such as, for example, rice or potato starch. Generally speaking, the more of an ingredient, the greater the affect on gluten.
Conditioners also can be added during mixing. Some strengthen gluten, others weaken it.
GLUTEN COAGULATION. During baking, gluten coagulates, or becomes firm. This, along with the gelatinized starch, creates the firm, springy structure of yeast bread. Without enough gluten the baked product would readily crumble and fail to spring back if squeezed.
Knowing the properties of quality flour may not help a pizzeria owner with dough-making but, if nothing else, it can be used for bluffing. When a distributor thinks you know the difference between good and poor quality, he’s more apt to send you a better-quality brand.
COMPOSITION. Good flour has 12 to 13 percent moisture content with 14 percent being the maximum, less than 1/2 percent ash or mineral (“ash” is the mineral residue left after completely burning the flour), and about 1 percent fat. When moisture, ash, or fat exceed the specified level it can adversely affect baking performance. (The USDA specifies that moisture should not exceed 15 percent.)
For pizza, protein level should be between 10 to 14 percent. The exact amount depends on what makes the best crust for your style pizza and dough-making methods. When in doubt, go with the higher amount of protein.
COLOR. Good bread flour is white with a slight creamy tint. A gray, dull color indicates poor flour. This can be seen by patting a small amount of flour into the bottom of a pizza pan, dipping it quickly into water, and then placing it in an oven for 30 to 40 seconds.
PROTEIN QUANTITY AND QUALITY. For years bakers have considered the quantity, or percent, of protein in flour to be the most important feature in separating good from poor bread flour. However, experts point out that quality of protein is also significant. They note that a flour containing a moderate amount of top quality protein will produce a good yeast bread, but a flour with a high amount of low quality protein will yield a poor bread. Of course the goal for most pizzerias is to have both—that is, a flour containing a high amount (i.e., 12 to 14 percent) of top quality protein.
A discussion of protein quality raises the question: “How does a miller or baker determine whether a flour has high or low quality protein?” The only way is by mixing the flour into dough and evaluating its handling and baking performance. If it performs as desired, we conclude that the flour contains high quality protein.
To confuse matters, different baking experts consider different things when evaluating protein performance. And they also use differing tests for doing it. However, generally speaking, a flour with good quality protein will: (1) have high water absorption capability for the amount of protein, (2) require a medium to high amount of mixing, (3) be tolerant to over- or under-mixing and also tolerant to over-fermentation, and (4) retain a maximum amount of gas from fermentation and, so, produce a pizza crust of good volume (considering the level of protein). A bread flour that does these things is referred to as a strong flour, or a flour with strong protein. One that doesn’t is termed a weak flour.
In summary, a good pizza flour retains its strength during mixing and kneading and does not become overly slack in fermentation. It forms a pliable, elastic dough that’s capable of holding gas from fermentation and will bake up into a crust with a full cellular network. A basic lean dough containing 58 percent water, made from good pizza flour, will mix for at least 10 minutes at second speed (about 125 rpm agitator speed) in a planetary mixer without slackening or diminishing in gluten elasticity.
WATER ABSORPTION CAPACITY. Water absorption capacity is the percentage of water a flour can absorb without becoming overly sticky or slack. A good flour of 12 percent protein content (and 12 to 13 percent moisture) can absorb up to 58 to 59 percent of its weight in water and still produce a non-sticky, good-performing yeast dough.
As a general rule, water absorption capacity increases by 1 to 1.5 percent of flour weight for each 1-percent increase in protein level. So the higher the protein level, the greater a flour’s water absorption capacity. In addition, a flour’s water absorption capacity is affected by the quality of protein, with higher quality protein absorbing more water than lower quality protein does. Finally, an overly dry flour—one that has been stored for a period in a room below 60 percent relative humidity—will have a moisture content below 12 percent and, as a result, will absorb a percent or two more water.
PROTEASE LEVEL. Gluten strength also can be affected by protein-attacking enzymes—most notably, proteases (sometimes called proteinases). High protease levels break down gluten molecules, causing the gluten to loose elasticity or strength. Sprouted wheat has a higher than normal level of protease enzymes. If desired, protease can be added to a mix.
AMYLASE LEVEL. Starch is comprised of very long molecular chains—thousands of carbon atoms strung together. When exposed to amylase enzymes these long molecules are broken down into shorter molecules—namely, dextrins which are of medium length and maltose which is a short-chain sugar that’s digested by yeast. A certain amount of maltose aids fermentation and a certain amount of dextrin aids baking. However, too much dextrin results in a sticky, gummy crumb in bread and a gummy layer in pizza.
Good pizza flour has an optimum level of amylase enzymes. To achieve that, millers often add malted barley flour or fungal enzyme. Too little amylase results in low fermentation. Too much produces a sticky crumb and, possibly, a complete gummy layer in the crust. One cause of too much amylase is wheat sprouting. Another cause is adding too much malted flour or other amylase-carrying ingredient at the mill or in the pizzeria.
Amylase level should be such that if measured on a Falling Numbers machine, the falling number will be in the range of 225 to 275. If potassium bromate is added the bromate should not exceed 15 parts per million (ppm); however, some high-gluten flours go as high as 20 ppm.
DAMAGED STARCH GRANULES. In wheat endosperm, starch exists inside microscopic granules. Amylase cannot attack it there. However, during milling the kernel is crushed and ground, causing the endosperm cells to break open. At the same time a percentage of the starch granules contained inside also break open, or rupture. The percentage of damaged granules is important because it can have a pronounced effect on a flour’s baking performance. This occurs because amylase enzymes readily attack the starch of damaged granules and decompose it into dextrins and sugar (maltose). The higher the percentage of damaged starch granules, the greater the breakdown of starch into dextrins and sugar.
Research shows that when the amount of damaged starch granules is 5 to 8 percent of total starch weight, it aids baking performance. However, when there’s too little, under-fermentation can result. On the other hand, too much can cause over-fermentation along with a sticky, gummy crumb and possibly a gummy layer. In short, over-abundance of ruptured starch granules has a similar effect as an over-abundance of alpha-amylase caused by (a) sprouting or (b) using too much malted flour or other amylase additive.
Because hard wheat has a more brittle endosperm than soft wheat, the milling process produces a greater percentage of ruptured starch cells with hard wheat than with soft.
GRANULE SIZE. Starch granules come in three sizes: small, medium, and large. The percentage of each type varies greatly between varieties of wheat. Research has shown that flour with a lesser percentage of small granules and a greater percentage of large granules performs better in baking.
In summary, from the standpoint of starch and amylase, the best flour for pizza baking contains minimum ruptured starch cells (5 to 8 percent of flour weight), a minimum level of small starch granules, and an optimum level of amylase enzymes (which requires that flour contain a minimum of unsprouted wheat endosperm).
Baking technologists have created various methods and machines for testing the properties of flour. Most devices are expensive and require special skills. A high-volume commercial bakery, and possibly a large pizza commissary, might use a couple of them.
Two of the most common testing devices are the farinograph and the “Falling Numbers” machine. The farinograph is a small mixer connected to a graphing device. From mixing a small batch of test dough it charts, among other things, the water absorption capacity and mixing tolerance of a flour. A flour’s water absorption capacity is the percentage of water needed to produce a dough of a given consistency. Generally, the higher the water absorption capacity, the better the flour. Mixing tolerance refers to how quickly a dough breaks down during continued mixing after reaching its peak development. Mixing tolerance is a key indicator of gluten strength. The more mixing tolerance a dough has, the greater fermentation and mechanical abuse a flour (dough) can tolerate.
The “Falling Numbers” machine is a simple device used for measuring the degree of alpha-amylase activity in flour. An acceptable falling number for pizza flour is in the range of 225 to 275. This test is required for all flour purchased by the government. It’s simple and can be done in a pizzeria. For information on where to purchase such machines, contact the American Institute of Baking (913-537-4750 or 800-633-5137).
Another test, which requires no equipment and has been used for years by bakers, is the gluten ball test. It’s used for comparing the protein levels of different flours, and can easily be done in a pizzeria. Here’s how to do it.
Measure out exactly 6 oz of each type of flour being tested. Mix each flour with enough water (approximately 3 oz) to make a stiff dough, knead it for five minutes, then allow it to rest for fifteen minutes. After that, wash each dough ball under a stream of cool water, kneading constantly until the water runs clear and all that remains is a rubbery mass. This is pure gluten. Place the ball on a paper towel for one minute, to drain off excess water, then weigh it. The heaviest ball indicates the flour with the most protein.
For further comparison, form each gluten piece into a smooth ball and place them on a pan, allowing at least 3 inches between them. Bake them in a hot oven (450 to 500 degrees F) for about an hour. The balls will expand. After baking compare their size. Generally speaking, the largest ball indicates the flour with the most and, possibly, highest quality protein.
The ultimate test of a flour is the baking test. To do it, make identical batches of dough using two different flours, or a new flour and your current flour. Have everything exactly the same except for the flour. Prepare identical pizzas and bake them the same. After cooling for 10 minutes, turn them over and cut them in half through the bottom of the crust with a razor blade or X‑acto knife. Examine the side of the crust. Look at color, cellular structure, and height of rise. Also examine the color of the outer edge, or collar, and the bottom of the crust. Then scrape off the sauce and cheese and, finally, taste both the outer edge and the “cleaned-off” center crust. Compare texture, flavor, and aroma. Choose the flour that performs best in the test.
A more detailed explanation of this test occurs in the chapter on Dough-making.
Flour comes in many types and quality levels. For successful dough-making a pizza manager must know about purchasing and handling it.
A typical neighborhood bakery stocks three types of white flour: bread, pastry, and cake flour. Of the three, bread flour has the highest protein content (11 to 14 percent); cake flour has the lowest (7 to 8 percent); and pastry flour is in between (9 to 10 percent). Bread flour is used for yeast breads, cake flour is used for cakes, and pastry flour is used for pastries, pie crust, muffins, biscuits, and corn bread. All-purpose flour, which is a blend of flours for home use, has a protein level in the 10 to 11 percent range.
Most pizza crusts are made with bread flour. Although there’s no hard-and-fast rule regarding pizza flour protein level, the following numbers can be used as a guide. To impart firmness to the crust, most thin crust pizzas are made with the highest protein flour, in the 13 to 14.5 percent range. It’s often called high-gluten flour. Medium-thick pizzas might use a slightly weaker flour in the 11.5 to 13 percent protein range. And thick crust or pan pizzas might use a flour with protein in the 10 to 11.5 percent range. As a rule, the thinner the pizza, the more protein the flour should have. If in doubt about what level is best for your pizza, go with 13 to 14 percent protein, or high-gluten flour. However, the above rule-of-thumb is a general guide which can certainly have exceptions. A pizzeria should use whichever flour produces the type of crust most preferred by its customers.
As regards bread flour there’s no difference in baking performance between bleached and unbleached flour. The only distinction is color. Bleached flour produces a white crumb. Unbleached gives a slightly yellower, creamier look. Choose the one that best suits your crust appearance objectives.
There’s a physical difference between hard wheat and soft wheat flours—or between high-protein bread (pizza) flour and low-protein cake flour. Bread flour has a creamy color, feels coarse when rubbed between the fingers, and if pressed into a clump will tend to crumble after pressure is released. On the other hand, cake flour has a white color, feels soft and smooth like talcum powder when rubbed between the fingers, and tends to clump and hold its shape if squeezed in the hand.
Bread flour is best for dusting a rolling table or flouring a dough ball before rolling or pressing, as it has less tendency to clump up on the dough.
For most pizza, we recommend purchasing bread flour. Specify the desired protein level—10 to 11.5 percent, 11.5 to 13 percent, or 13 to 14.5 percent. If in doubt, buy the top level, or high-gluten flour. NOTE: Since there’s no official definition for high-gluten flour, not all flours labeled “high-gluten” perform the same. Some perform like “medium-gluten” flour.
For the lowest priced flour of acceptable quality, specify straight grade flour. It contains 100 percent of the flour yield from milling a batch of wheat.
For the top quality bread flour, specify short patent. It’s sometimes called fancy patent, and consists of the first 75 to 80 percent of the flour yield. It makes the whitest crumb, but will often be lower in protein content than straight grade.
For a middle-of-the-road flour, in both quality and price, specify a medium patent—also known as baker’s flour or standard flour. It should consist of the first 90 percent of flour yield.
Avoid using a clear grade of flour—which is flour that comes after patent flour—unless you’re combining it with whole wheat flour or some other dark ingredient. In which case, use a good grade of clear such as fancy clear or first clear.
For pizzerias, flour comes in 100 lb and 50 lb bags, and sometimes 25-pounders. For ease of handling, a 50 lb bag is preferred over a 100-pounder, especially if your dough-maker isn’t large and strong.
Flour is produced by both large and small milling companies. They market it under their own name. They also pack it under various labels or brands for distributors. So there are hundreds of brands on the market, many of them containing nearly identical product.
Millers attempt to provide the same flour year to year for each brand. However, as weather changes from crop to crop so does flour composition. So it’s possible for flour packed under the same label to vary annually. Because of possible fluctuation, large bakeries test each batch of flour before using it.
If, all of a sudden, your flour performs differently, it might be that it’s a slightly different flour—that is, from a new wheat crop. At this point you have three options:
1. Make a slight adjustment in the amount of water used and/or the mix time. This will usually be enough to bring flour performance back to normal.
2. Test other brands or types of flour.
3. Try a dough additive (or increase/decrease what you’re now using).
Generally, the first thing to do is adjust the water portion and/or mix time. If that doesn’t work, test a different flour. If the perfect flour can’t be found, then look for an additive.
A pizzeria owner should be aware that millers have a lot riding on their brand names. To keep customers they must maintain quality and consistency from year to year. So they do everything in their power to achieve that. As a result, major brand names are likely to be more consistent than generic product and distributor labels. Although major brands sometimes cost a little more, many pizzerias willingly pay it to be assured of quality consistency. (This applies to tomato products, cheese, and toppings, as well.)
Finally, we stress the importance of building a working relationship with your flour miller and/or distributor. The good ones have technical experts who, with a quick phone call, can often give the solution to a flour/dough problem and, thereby, save you time and money. This approach also applies to solving tomato product, cheese, and topping problems.
Flour absorbs moisture and, so, should be stored in a well-ventilated, dry place. Ideally, it should have 12 to 13 percent moisture. When it absorbs over 14 percent it may not perform well. If humidity can be controlled, keep it around 60 percent.
The best storage temperature is 75 to 80 degrees F. Flour doesn’t perform well when cold, so should not be stored in a walk-in refrigerator. If it is stored cold it should be warmed to 70 degrees F for a day before using.
Store it off the floor on a pallet or on a storage shelf. Criss-cross the bags to provide good ventilation. Maintain a 12-inch space between flour bags and the wall. Flour absorbs odors, so keep it away from onions, garlic, and the like.
Mice and insects attack flour, so good pest control is important.
Because flour deteriorates in excessively prolonged storage, a pizzeria should avoid using it over a year old.
In recent years pizzeria managers have experimented with supplementing white flour with other types of flours and meals. (Meal is coarsely ground endosperm of cereal.) It can add new flavor, color, texture, and nutritional properties to a crust. If used in the wrong proportion it can also result in a crust of lower volume and unacceptable flavor and appearance to many customers. Here’s some thoughts on supplemental flours and meals.
The only way to determine what kind and how much supplemental flour or meal will yield a quality crust is to experiment. For testing purposes any type of flour can be blended with white flour. Some to consider are: whole wheat (or graham), rye, corn, oat, triticale, millet, buckwheat, potato, rice, soybean, peanut, and cottonseed flours. In addition, there are various coarsely ground cereals or meals which can provide interesting color and texture. Some common ones are: corn meal, rye meal, oat meal, wheat bran, wheat germ, and semolina (coarsely ground durum wheat).
The amount of supplemental flour that can be used with good results varies greatly. The only way to find out what works is by testing. In doing so, start with a small percentage—generally, about 10 percent—and work upwards. Here’s some things to try.
WHOLE WHEAT FLOUR is flour that’s milled from the entire wheat grain, which includes the starchy white endosperm, the fatty germ portion, and the outer layer known as the bran layer. The bran is darker colored than the endosperm and has a somewhat bitter flavor. This dark color and bitter flavor comes from tannins contained in the bran. Because whole wheat flour has a higher fat content, it should be used within six months to prevent rancidity.
To create a whole wheat crust recipe, start by substituting 20 percent of the white flour with whole wheat flour. In fact, the entire crust can be whole wheat flour, but it tends to produce sticky dough and weaker, lower volume crust with a distinctively different (almost bitter) flavor. For a lighter color and less bitter taste in your whole wheat crust, use a whole wheat flour that’s milled from hard white wheat. The bran layer of this particular strain of wheat contains a smaller amount of tannins than does the bran of regular (i.e., red) wheat. So whole wheat flour that comes from white wheat has a lighter color and less-bitter flavor than that which comes from red wheat. White wheat is not as widely produced as red wheat, but it’s becoming more available as more and more bakeries use it in whole wheat breads. For a source, try contacting the American White Wheat Producers Association: 913-367-4422.
RYE FLOUR. There are three varieties of rye flour: white, medium, and dark. With a medium rye, bakers use up to 25 percent.
POTATO FLOUR has long been used by bakers as a flavor enhancer. For starters, try 5 percent.
SOYBEAN FLOUR has attracted interest in recent years for nutritional reasons. It has a very high protein content and complements flour proteins well. Unfortunately, high levels adversely affect dough and result in poor volume, color, and flavor of the bread. One bread recipe recommends 12 percent soy flour, 5 percent sugar, and 2 percent salt (based on flour weight). To improve dough firmness it also suggests using a dough strengthener, such as sodium stearoyl lactylate, in the amount of 0.25 to 0.5 percent.
YELLOW CORN MEAL has long been used in certain Chicago-style deep dish pizzas, in the range of 10 to 15 percent of white flour. For variation, try white corn meal.
SEMOLINA can be used to impart chewiness and richer color. Test 10 percent. Some people also use a 50:50 mixture of semolina and white flour for dusting purposes.
WHEAT GERM OR BRAN can be added in the amount of 2 to 5 percent of flour weight.
Items that some people feel tend to have a “crisping” effect include corn meal, corn germ, rice flour, pea flour, and pea fiber.
All supplemental flours and meals change the character of dough—some a lot, some a little. When experimenting, be prepared to adjust the amount of water and yeast and also length of mixing and fermentation time to obtain a dough of proper rise, firmness, and workability. In addition, because supplemental flour reduces the dough’s overall gluten level, you may need to add a gluten strengthener or, possibly, some vital wheat gluten in the amount of 1 to 2 percent of flour weight, or switch to a high-gluten flour if you’re not currently using one.
Water plays a critical role in baking. First, the amount of water affects dough
consistency. By changing the amount we can make dough stiffer and slacker. Second,
water affects dough temperature—by controlling the temperature of the water we
effect the temperature of the dough. Third, water acts as a dispersing medium,
bringing dough components into contact with each other. Fourth, it dissolves
the salt, sugar, and other dry ingredients. Fifth, it hydrates the glutenin and
gliadin proteins, allowing them to combine and form gluten. Finally, during baking,
water combines with starch in the process of gelatinization which, along with
coagulation of gluten, gives body and firmness to the baked good.
For convenience, bakers refer to dough ingredients as a percentage of flour weight. For example, if a recipe calls for 25 lb flour and 15 lb water, we would say that it consisted of 60 percent water (15 ÷ 25 = .60 or 60 percent). We call that a baker’s percent. Throughout this book we use baker’s percents. As applied to water, pizza dough typically contains 40 to 60 percent water. In a lean dough recipe, forty percent water makes a very stiff dough. Fifty percent makes a medium stiff dough. And sixty percent makes a very soft dough. Most bread dough, such as for Italian or French bread, usually contains 58 to 60 percent water.
We point out that water for dough not only comes from pure water but also can come from other liquids, such as, for example, potato water, milk, and beer.
In addition to the amount of water, two conditions of water affect dough. They are hardness and pH (acidity-alkalinity). We examine each.
Various minerals can be found in water. Two of them—calcium and magnesium—play a major role in water hardness and also in dough-making. The type and amount of these minerals varies with the locale.
Medium-hard water—that is, water with 50 to 100 ppm (parts per million) of carbonates—is the best for baking. It contains the right amount of mineral salts—mostly of calcium and magnesium—which strengthen gluten and also, to some extent, serve as yeast nutrients.
Soft water (less than 50 ppm carbonates) has a shortage of those salts, which tends to result in a soft, sticky dough because there’s less gluten-tightening effect from minerals. To counteract stickiness, reduce the water portion by about 2 percent. It can also help to increase the salt portion up to 2.5 percent of flour weight. On the baked pizza, the soft water tends to produce a crust texture and color that’s less than optimum.
Hard water (over 100 ppm carbonates) has too much of the salts. This toughens gluten excessively, which retards the fermentation or rise of dough. To counteract that, increase the yeast level and, if it’s used, adjust the amount of yeast food. Also, adding malt or malted flour might help.
Water from a city source usually has a proper degree of hardness for good dough development. However, a pizzeria in a small town or one that draws ground water might have excessively hard water.
To measure acidity and alkalinity, science created the pH scale (pronounced pee-AYCH). It describes the acidity or alkalinity of a solution, including foods, in terms of a number called a pH value, which ranges from 0 (zero) to 14.
A neutral substance (neither acidic nor alkaline) has a pH value of 7.0. Acidic substances have pH’s below seven, with acidity increasing as pH approaches zero. Alkaline substances have pH’s above seven, with alkalinity increasing as pH approaches fourteen.
Examples of acidic foods are milk (pH6.5), tomato juice (pH4), apple juice (pH3), and lemon juice (pH2). Examples of alkaline foods are ripe olives (pH7.5), soda crackers (pH8), and baking soda (pH8). Soap has a pH of ten. Acidic foods tend to taste sour; alkaline foods tend to taste bitter.
Pure or distilled water has a pH of 7.0. However, with the addition of minerals and other substances, it becomes either acidic or alkaline.
pH is important in dough-making because it affects chemical and biological reactions. Most notably, it affects the rate of amylase enzyme performance (conversion of starch to sugar) and, as a result, the rate of fermentation. The optimum pH for starch conversion and fermentation and, hence, for pizza dough, is about five, or slightly acidic. This pH level is best achieved by using water with pH6.5 to 8.0, with pH7.0 being the optimum.
Highly acidic water (below pH6.5) is uncommon because cities treat water to remove acidity—as it corrodes pipes.
However, highly alkaline water (above pH8.0) can occur. Such water tends to reduce the fermentation rate of pizza dough. To counteract it you can (1) acidify the water by adding acetic acid (i.e., vinegar), lactic acid, or monocalcium phosphate; (2) add a mineral conditioner or “yeast food” (e.g., an ammonium salt); or (3) allow more fermentation time. Also, some yeast strains are tolerant to high alkalinity while others are not. You might try a different brand of yeast to see if one performs better in your type of water.
An independent pizzeria might not even know it has alkaline water because it probably already corrected for the effect by increasing fermentation time. However it’s not uncommon for a chain with standardized recipes and procedures to open a store in a town with highly alkaline water and find their dough performing differently. In that case one of the adjustments described above might help.
If you have a serious water problem that you can’t correct, talk to your local water company about ways to remedy it. They can often provide a water analysis and technical assistance, usually at no charge.
The most common leavener used in pizza crust is yeast. Yeast, technically called
Saccharomyces cerevisiae, is a single-celled plant of the fungi family.
There are numerous strains, some of which are used in baking and brewing. Each
type of baking yeast requires a different strain. In an ounce of yeast there
are billions of yeast cells. Yeast can reproduce through several methods, the
most common being budding. This involves the growth of a small bud on the side
of the cell. The bud eventually breaks off and forms another cell. For a photo
of yeast cells, click
here.
Yeast is manufactured by immersing the cells in a solution of sugar and nutrients. The cells reproduce until they are harvested, at which time the yeast-rich mixture is either shaped into crumbles or blocks for wet yeast, or is extruded and dried for dry yeast.
For energy, yeast mainly digests simple sugars—notably, glucose and fructose—in a process called fermentation. The main by-products of fermentation are ethyl alcohol and CO2 gas (i.e., carbon dioxide). The alcohol is key to making alcoholic beverages. CO2 is what leavens bread, or causes it to rise. If oxygen is available, as it is in dough, yeast continues to decompose the alcohol into more CO2 plus water. In addition some heat is produced along the way. So, as a result of fermentation yeast puts CO2, water, and heat into the dough.
In addition, fermentation produces small amounts of other important by-products (e.g., volatile esters and aldehydes) that enhance pizza crust aroma and flavor.
Finally, yeast releases small amounts of proteolytic (protein-decomposing) enzymes. These enzymes act to condition the gluten, or make it more extensible, as long as the dough’s salt content is under 1 percent. (Over 1 percent salt inhibits the protein-decomposing action by enzymes.)
If simple sugars aren’t available, yeast can decompose more complex sugars—namely, sucrose and maltose—into glucose for fermentation. To perform this function it has special enzymes within its cell. Sucrose and maltose come from one or both of two sources. It can be included in the dough recipe and/or it can be created within the dough when amylase enzymes in the dough decompose the starch into maltose.
Yeast provides fermentation and fermentation does five things. First, it leavens or expands the dough’s volume through CO2 gas. This makes for a more risen, tender crust.
Second, it makes the dough slacker and more extensible, which increases the dough’s stretchability, or sheetability. This is accomplished by gluten-relaxing enzymes and by a small amount of water produced during fermentation. The main gluten-relaxing enzyme is protease. The fermentation process also yields amylase enzyme which converts the starch in the dough to dextrin and maltose.
Third, fermentation enhances the flavor and aroma of the crust. This is accomplished by production of certain acids—namely, lactic acid and acetic acid. These acids promote denaturalization of flour proteins during baking which, in turn, create the wonderful yeast-bread flavor of a properly-risen pizza crust. Generally speaking, the more fermentation there is, the more flavor there is, up to a point. Acids also have the effect of increasing the dough’s extensibility.
Fourth, fermentation produces propionic acid, which acts as a natural mold inhibitor in breads and pizza crusts. The more fermentation there is, the greater the amount of propionic acid and, as a result, the greater resistance to mold growth. This has little application for a pizza that’s consumed shortly after baking, but it could be a consideration in production of parbaked crust.
Fifth, fermentation in the proper amount greatly reduces, even eliminates, bubbling in crusts during baking. For more on this see the Crust Bubbling discussion in the Dough and Crust Trouble-shooting chapter.
To obtain a quality crust the proper amount of dough rise must be achieved before baking. Too much or too little can result in a sub-standard product. The amount of rise is determined by two main factors:
1. Amount of yeast in the dough;
2. Rate of fermentation by the yeast—that is, how quickly the yeast digests sugar. This is known as yeast activity.
The amount of yeast is determined by either the recipe or the dough-maker’s discretion. The rate of fermentation is determined by a number of dough conditions. So to change the amount of rise, a pizzeria can change the yeast portion (the more yeast, the faster the rise) and/or change one or more conditions affecting fermentation rate.
A number of conditions affect the rate of fermentation, or the rate at which yeast digests sugar.
DOUGH TEMPERATURE. Dough temperature is a key factor affecting fermentation rate. At 33 degrees F yeast works very slowly. As temperature rises, fermentation continues to accelerate up to 100 degrees, after which it begins to slow down until it reaches approximately 140 degrees, when yeast dies. The rule is: For every 18 degrees F (or 10 degrees C) increase in dough temperature (up to 100 degrees F), yeast activity doubles, or increases by 100 percent. So, for example, the fermentation rate of 88 degree F dough will be twice that of 70 degree dough; and 70 degree dough will be twice that of 52 degree dough.
For fastest fermentation, bring dough from the mixer at 90 to 100 degrees F and keep it there. For slowest fermentation, bring it from the mixer at 65 degrees or below and cool it quickly down to 32 degrees. Because coldness acts to retard fermentation, bakers often call cold dough retarded dough and the refrigerator it’s kept in is called a retarder. (For more information on managing dough temperature, see the chapter on Dough Management.)
As the season changes so does inside air temperature. And as air temperature changes, so does dough temperature, which affects the rate of fermentation. For that reason many pizzerias reduce the yeast portion in summer and increase it in winter. The change may be as much as 20 to 30 percent. Another way to counteract seasonal temperature changes is to adjust dough water temperature—warmer in winter, cooler in summer. (For more information on dough water temperature, see the section on Dough-making Steps in the Dough-making chapter.)
AMOUNT OF SUGAR. Sugar is what yeast eats. Mixing small amounts of sugar into dough—up to 5 percent of flour weight—speeds fermentation. Over 5 percent, sugar pulls water from the yeast cell by osmosis, which slows down fermentation. To overcome this effect, yeast content is often increased for sweet doughs.
TYPE OF SUGAR. Yeast responds more quickly to some sugars than to others. It digests glucose, sucrose, and fructose the quickest. However, it doesn’t begin to digest maltose until these three sugars are nearly used up. On the other hand, lactose, or milk sugar, is not digested by yeast at all and, therefore, doesn’t promote fermentation. In fact, lactose can actually slow down fermentation due to it’s lowering of the dough’s pH.
AMOUNT OF AMYLASE AND DAMAGED STARCH GRANULES. Dough develops sugar when amylase enzymes decompose damaged starch granules into maltose. So the more amylase and/or damaged starch granules there are, the more maltose is produced. Amylase content is increased by adding any one of several amylase-containing ingredients, such as malted flour or fungal enzyme. It also could be heightened when sprouted wheat is used in making flour. To maintain consistent amylase content in a brand of flour, millers adjust the amount of malt or enzyme that they mix in.
AMOUNT OF SALT. At levels of one percent or less of total flour weight, salt has little or no effect on fermentation. However, over one percent it begins to pull water from yeast by osmosis, which slows down fermentation. At two percent the slowing effect is quite noticeable. In addition to sodium chloride, other chlorides will produce that effect, as well.
ACIDITY. Fermentation is fastest in a moderately acidic medium (pH4.0 to 6.0). Typical pizza dough should have a pH in the 5 range.
AMOUNT OF NUTRIENTS. To support fermentation yeast needs nutrients—that is, nitrogen, vitamins, and minerals. Much of those elements are provided by flour and water. However, if needed, additional amounts can be added in the form of “yeast food.” Yeast food is a broad name for chemicals that stimulate fermentation. The basic ingredient in yeast food is an ammonium salt—namely, ammonium sulfate, ammonium chloride, or ammonium phosphate—which supplies nitrogen to the yeast.
In addition, some yeast foods also contain oxidants, such as potassium bromate, which condition the gluten, along with salts for adjusting dough pH. Because of their various chemical make-ups, a yeast food, if it’s used, should be carefully selected to complement the type of water.
TEMPERATURE OF REHYDRATION WATER. Active dry yeast must be rehydrated before using. During rehydration the yeast’s cell wall absorbs water and resumes its normal, firm condition. However when rehydrated in cold water various materials are leached from the yeast before the cell wall can firm up. This results in a lower fermentation rate and also creates a stickier, slacker dough which may not bake up well. For that reason a dough-maker should always measure the temperature of rehydration water.
TYPE OF YEAST. How quickly yeast begins fermentation depends on the form used. Mainly, compressed yeast is the quickest, instant yeast is next, and regular active dry yeast is slowest.
Except for instant dry yeast, it’s usually best to rehydrate yeast, or combine it with water before mixing. The resulting liquid is called “yeast water” or rehydration water. Use approximately 10 percent of the water called for in the recipe, but not less than 4-times the weight of yeast. For example, 4 oz of yeast would require a minimum of 16 oz, or one pound, of rehydration water. Even though instant yeast is typically added dry to the dough mix, it can be rehydrated, as well, if the operator chooses.
Rehydrate yeast for 5 to 10 minutes before mixing. Do not rehydrate it over 15 minutes.
Some dough-makers like to start the fermentation process in the water. This assures them that the yeast is alive. To do that, stir in a pinch of sugar or a sprinkle of flour before adding the yeast. After 5 to 10 minutes a foam will form on top, an indication that the yeast is starting fermentation, or “blooming” as it’s called. If no foam develops, that means the yeast is dead. Because salt inhibits yeast activity, do not add salt to the water until just before mixing.
Before adding yeast water to the mixer, give it a stir to disperse the yeast.
Yeast comes two basic ways: wet and dry. Wet yeast includes compressed, crumbled, and cream varieties. Dry yeast consists of regular active dry yeast, instant dry yeast, and protected dry yeast. In total there are six varieties of yeast. Each is discussed separately.
Compressed yeast—also called cake, block, fresh and baker’s yeast—is the oldest of the six forms of yeast. When a recipe simply calls for “yeast” this is usually what’s meant. It comes in one pound blocks and has a 70 percent moisture content.
Before mixing, crumble compressed yeast into warm (70 to 90 degree F) water and let sit for 10 minutes. It can also be crumbled and added directly into the flour, but we don’t recommend this method because it might result in uneven distribution of the yeast.
The amount of yeast used depends on the rate of fermentation, or speed of rise, desired. And the speed of rise desired depends on whether the dough will be made into pizza soon after mixing or will be retarded for, say, three