Mastering Brewing Science
Description
Focused on brewing science, process, and quality, this is a comprehensive textbook on beer production, from the underlying biology and chemistry to process steps, packaging, testing, and service of beer and related products.
Mastering Brewing Science is a complete resource for brewing students as well as established professionals, with coverage of brewing processes, beer quality assurance, and related industries such as hop and malt preparation. The text strikes a balance among essential scientific concepts, treatment of raw materials, procedures and equipment for beer brewing, and protecting and evaluating product quality. Understanding the science of beer production will enable readers to troubleshoot problems in the brewery, a critical skill for a career in beer.
Mastering Brewing Science begins with a high-level discussion of the brewing process. Subsequent chapters review the fundamentals of biology and chemistry with application to the brewing process. The remaining material covers the processes and procedures to make quality beer and related beverages, including a focus on each of the four raw materials. Hundreds of illustrations, many in full color, explain the equipment and processes.
The newly revised and updated Second Edition of Mastering Brewing Science includes:
- End-of-chapter review questions.
- Twenty-six 'Case Studies' focused on real-world, practical problems for discussion.
- Coverage of alternative beverages including low alcohol beer, gluten-free beer, flavored malt beverages, hard seltzer, hemp beer, high-gravity brewing, and brewing with bacteria.
- Expanded coverage of water, malt, hops and yeast, each with its own chapter.
- Techniques for effective standard operating procedures (SOPs).
- Strong coverage of workplace safety throughout, with all safety coverage tabulated together in the index.
- Many procedures for beer preparation and quality testing of beer, raw materials, and packaging. All procedures are tabulated in the index.
Mastering Brewing Science is an essential learning resource for students in brewing science or technology programs or as a valuable resource for brewing professionals.
Matthew Farber, PhD is the founding director of the Brewing Science Certificate program at Rowan University in New Jersey, where he is Associate Professor of Biology.
Roger Barth, PhD is Professor Emeritus of Chemistry at West Chester University in Pennsylvania. He is the creator of a course on the chemistry of beer.
More details
Other editions
Additional editions
Content
Preface xi
Acknowledgments xiii
About the Authors xvii
About the Companion Website xix
1 Brewing Quality Overview 1
1.1 Ingredients 2
1.2 Brewing Overview 3
1.3 A Scientific History of Brewing 13
1.4 Introduction to Beer Quality 22
Case Study 27
Case Study Questions 27
Check for Understanding 27
Bibliography 28
2 Chemistry for Brewing 31
2.1 Atoms 31
2.2 Bonding and Compounds 36
2.3 Molecules 43
2.4 Intermolecular Forces 47
2.5 Structure of Molecules 50
2.6 Organic Chemistry and Functional Groups 52
2.7 Chemical Reactions 55
Check for Understanding 59
Bibliography 61
3 Biology for Brewing 63
3.1 Macromolecules 63
3.2 Membranes 83
3.3 Cellular Structures 85
3.4 The Central Dogma 88
Check for Understanding 96
Bibliography 97
4 Water 99
4.1 Water Chemistry 99
4.2 Water Profiles and Adjustment for Brewing 111
4.3 Analytical and Quality Control Procedures for Water 116
Check for Understanding 117
Bibliography 118
5 Malt 121
5.1 Barley Biology 121
5.2 The Malting Process 125
5.3 Types of Malt 130
5.4 Analytical and Quality Control Procedures for Malt 135
Case Studies 145
Check for Understanding 146
Bibliography 146
6 Hops 147
6.1 Hops Biology 147
6.2 Hop Flavor Chemistry 152
6.3 Hops Processing and Products 157
6.4 Hop Dosing 163
6.5 Analytical and Quality Control Procedures for Hops 164
Case Study 165
Check for Understanding 166
Bibliography 167
7 Grain Handling and Milling 169
7.1 Malt Storage and Transfer 169
7.2 Malt Infestations and Pest Control 177
7.3 Milling 179
7.4 Analytical and Quality Control Procedures for the Grist 184
Case Study 187
Check for Understanding 188
Bibliography 189
8 Mashing 191
8.1 Starch Hydrolysis 191
8.2 Enzymes 193
8.3 Mashing Process 201
8.4 Mash Conversion Vessel Design and Operation 206
8.5 Mashing Steps and Parameters 210
8.6 The Use of Adjuncts 214
8.7 Enzymes and Processing Aids 216
8.8 Analytical and Quality Control Procedures for Mashing 219
Case Study 220
Check for Understanding 220
Bibliography 222
9 Wort Processing 225
9.1 Wort Separation Processes 225
9.2 Management of Spent Grains 235
9.3 Wort Boiling 236
9.4 Boiling Technology 241
9.5 Hot Wort Clarification 251
9.6 Boiling Chemistry 253
9.7 Chilling 254
9.8 Knocking Out 255
Case Studies 257
Check for Understanding 258
Bibliography 259
10 Yeast 261
10.1 Yeast Biology 261
10.2 Yeast Handling and Repitching 267
10.3 Yeast Propagation 271
10.4 Active Dry Yeast 279
10.5 Unconventional Yeast 279
10.6 Yeast Hybridization 282
10.7 Analytical and Quality Control Procedures for Yeast 285
Case Studies 291
Check for Understanding 292
Bibliography 292
11 Fermentation 295
11.1 Fermentation Process 295
11.2 Fermentation Reactions 304
11.3 Energy and ATP 307
11.4 Oxidation, Reduction, and NAD 308
11.5 Fermentation Process and Equipment 312
11.6 Temperature Monitoring and Control 318
11.7 Analytical and Quality Control Procedures for Fermentation 324
Case Studies 331
Check for Understanding 331
Bibliography 332
12 Conditioning 333
12.1 Secondary Fermentation 334
12.2 Clarification 337
12.3 Carbonation 344
12.4 Beer Aging 349
12.5 Dry Hopping 352
12.6 Analytical and Quality Control Procedures for Conditioning 354
Case Studies 357
Check for Understanding 358
Bibliography 358
13 Packaging and Serving 361
13.1 Kegs and Casks 361
13.2 Gas Laws 367
13.3 Keg Dispense System 370
13.4 Bottles and Cans 377
13.5 Filling Bottles and Cans 380
13.6 Beer Service and Packaging Quality 389
13.7 Measurement of Beer Packaging Quality 390
Case Studies 395
Check for Understanding 395
Bibliography 396
14 Cleaning, Cip, and Sanitization 397
14.1 Cleaning a Brewery 397
14.2 Clean in Place 401
14.3 Cleaning Chemicals 405
14.4 Sanitizers 409
14.5 Analysis and Quality Control of Cleaning Effectiveness 411
Case Study 413
Check for Understanding 413
Bibliography 414
15 Good Brewery Practice 415
15.1 Brewery Safety 415
15.2 The Brewery Laboratory 431
15.3 Standard Operating Procedures 436
15.4 Managing Quality Data 438
Case Study 446
Check for Understanding 446
Bibliography 447
16 Flavor 449
16.1 Flavor Anatomy 449
16.2 Flavor Chemistry 454
16.3 Flavor Stability 463
16.4 Flavor Evaluation 468
Case Studies 472
Check for Understanding 472
Bibliography 473
17 Color, Foam, and Haze 475
17.1 Light and Color 475
17.2 Foam 482
17.3 Haze 490
17.4 Quality Control and Evaluation 496
Case Studies 503
Check for Understanding 504
Bibliography 504
18 Microbial Stability 507
18.1 Spoilage Microorganisms 507
18.2 Microbial Stabilization 519
18.3 Analytics and Quality Control of Microorganisms 526
Case Study 537
Check for Understanding 537
Bibliography 538
19 Related Products and Processes 541
19.1 Nonalcohol/Low Alcohol Beer 541
19.2 Gluten- Free Beer 548
19.3 Flavored Malt Beverages and Hard Seltzers 551
19.4 Hemp Beer 555
19.5 High- Gravity Brewing 558
19.6 Brewing with Bacteria 561
Check for Understanding 562
Bibliography 563
Glossary 565
Index 625
CHAPTER 1
BREWING QUALITY OVERVIEW
Overview. Bonesaw Brewing Co. Glassboro, NJ.
Photo: Naomi Hampson.
We wrote this book to help you better understand, appreciate, and apply the science behind the materials and processes of making beer. The better your grasp of brewing science, the more dependably you will be able to make delicious beer, and the more reliably you will be able to devise new beers to meet changing consumer preferences. So what is beer? How does beer differ from its fermented beverage brethren? The US legal definition is given in Section 19.3: "Flavored Malt Beverages"; a commercial definition encompasses the wide variety of products that are included in beer marketing, but in a book on brewing science, we will use a scientific definition. Beer is an alcoholic beverage derived from a source of starch without concentrating the alcohol content. "Derived from" covers a complex series of interacting steps, each of which influences the character of the final product and is ultimately the focus of this book. Brewing beer differs from fermentation of wine in that for brewing, a source of starch must first be converted into fermentable sugars. The brewer is responsible for management and control of all steps of the brewing process to produce a beer of reliable and reproducible quality.
There are four main ingredients in beer: water, malt, hops, and yeast. If randomly combined, these four ingredients might turn into an alcoholic beverage of questionable quality, but in this chemical process, the brewer is like a catalyst, a substance that guides and speeds up a reaction. Mastering the science of raw materials and the process steps of beer production is essential to making quality beer. We will start with a broad overview of the brewing process followed by a scientific history of beer and the scientific method. In learning how to conduct an experiment, you will begin to understand the process of troubleshooting problems in the brewery. Finally, as our major goal is to brew beer of excellent quality and consistency, we will discuss beer quality as defined in several contexts. Each of these topics will be discussed further in depth in the chapters that follow.
1.1 INGREDIENTS
In addition to the main ingredients, beer may be brewed with adjuncts and processing aids. Adjuncts are sources of starch or sugar other than malt. Processing aids are materials used to help give the beer desirable characteristics. Some common processing aids are filtration media, finings, carbon dioxide, foam enhancers, and coloring materials. In this overview, we will touch upon the main four ingredients. Adjuncts and processing aids are covered in later chapters.
Water
Beer is usually more than 90% water. Beer production can take as much as 12 volumes of water to make 1 volume of beer. Some breweries have been able to cut this ratio to three or less. Less water means less energy use, less wastewater for disposal, and less negative impact on the environment. Pure water is a characterless compound of fixed composition. It is supplied to breweries as a mixture with many components present in trace amounts. The nature and concentrations of these trace components are important to the character and quality of the beer. Water is usually modified to adjust the trace components. Water that is to be made into beer is sometimes called brewing liquor. Chapter 4 discusses brewing water in detail.
Malt
Brewing beer requires starch, which is usually derived from cereal grain. Malt is prepared from seeds of cereal grain by steeping (soaking in water), germinating, and drying. The malting process produces enzymes that convert starch to fermentable sugars. The most common grain for malting is barley (Hordeum vulgare), but wheat, rye, and oats can also be malted. Rice and maize (corn) can also be used as sources of starch for brewing but require special treatment. Since medieval times, malting has been a separate craft from brewing, requiring specialized facilities. Nonetheless, brewers need a basic understanding of the malting process to fully understand and apply malt as a raw material. Malt and malting will be discussed in Chapter 5.
Hops
The hop (Humulus lupulus) is a climbing plant, more specifically a bine. The fruits of the hop plant, hops, are boiled with the beer wort to provide bitterness and other flavors. Hops may also be added to the fermenter in a process called dry hopping. Hop compounds provide an antibacterial effect to help preserve the beer. There are many varieties of hops with different flavor profiles, as well as advanced hop products that can be easier to use than natural hops. Chapter 6 provides details about hops and their processing.
Yeast
Yeast is a single-cell fungus that converts sugar to ethanol and carbon dioxide. The action of yeast on sugar is fermentation. Most beer fermentation is carried out by one of two species of yeast: Saccharomyces pastorianus, used for lager beer, and Saccharomyces cerevisiae, used for ale. Some specialty beer styles are fermented with Brettanomyces bruxellensis, Brettanomyces lambicus, or related species. Within a particular yeast species, there are many variations, called strains. The species and strain of yeast affects the flavor and character of the beer. Yeast may be cultivated at the brewery or pitched directly from wet or dry commercial products. Processes and practices involving yeast are covered in detail in Chapters 10 and 11.
1.2 BREWING OVERVIEW
A graphical overview of the brewing process is provided in Figure 1.1. In brief:
- Malt and other grains are crushed in the mill. Crushed grain is called grist.
- The grist is loaded into the grist case until mashing.
- The grist is mixed with hot water in the premasher on its way into the mash tun.
- In the mash tun, enzymes from the malt cause the starch in the grist to be converted to soluble extract, which contains sugars that the yeast can ferment.
- The solution of extract, called wort, is separated from the remaining grist particles in the lauter tun. Extract that sticks to the particles is washed out with hot water in a process called sparging.
Figure 1.1 Overview of the brewing process in a four-vessel brewhouse.
Source: Drawing: Marcy Barth.
- The clear wort is boiled in the kettle. Hops are added.
- The remains of the hops and solids that form during boiling (hot break or trub) are removed in the whirlpool.
- The clear, boiling-hot wort is cooled in a heat exchanger called the wort chiller.
- During knockout, oxygen and yeast are added to the cool wort while it is pumped into a fermenter.
- After several days to more than a month of fermentation and conditioning, the yeast is removed from the beer, and the beer is pumped into the bright beer tank. Separation of yeast and solids may be facilitated by special equipment such as a centrifuge or filter. Carbon dioxide is added under pressure to provide the characteristic lively mouthfeel.
- The beer is served directly from the tank or packaged into secondary containers.
A summary of the duration and temperature ranges for each step in the brewing process is provided in Table 1.1. This table represents a general summary and overview; different breweries using different equipment and brewing different styles of beer may have quite different programs.
Milling
Malt is delivered to breweries in bulk (loose in a truck or rail car), in super sacks, or in bags. Malt must be milled, that is, crushed into small pieces to expose the starch, before it is used for brewing. Crushed grain is called grist. The device that performs the operation is a mill (Figure 1.2). The primary purpose of milling is to allow starch from the grain, enzymes from malt, and water to come into contact during the mashing step. A seed of grain is protected by a water-resistant seed coat, and a woody shell called the hull. Milling splits the hull, breaks open the seed coat, and crushes the interior of the seed, producing additional surfaces where water can react with starch. Milling details affect the character of the beer and the efficiency of the process. It is preferred that the malt hulls be split but not pulverized because they will be needed to aid wort separation later in the process.
TABLE 1.1 Brewing Steps, Durations, and Temperatures
Process Step Duration Temperature Milling 1-2 hours Ambient Mashing 1-2...