In the past two decades we have witnessed unprecedented changes in the U.S. beer industry. The emergence of craft brewers and consumers’ newfound appreciation for quality beer have resulted in what is often called the “Craft Beer Renaissance.” Beer has taken on a new excitement and relevancy to the average person. It is no longer thought of only in the context of large commercial brewers with their mass-marketed beers. The marked increase in the number of brew pubs and microbreweries and the burgeoning growth in the number of home brewers indicate how deeply brewing beer has captured the popular imagination.
The Brewer’s Handbook is intended to provide an introduction to brewing beer, and to give a balanced, reasonably detailed account of every major aspect of the brewing process. This book not only discusses brewing beer on a largescale commercial basis, it has made every effort to address brewing practices typically used by craft brewers. Thus its applicability extends to home brewers and to individuals working in the brewing industry and related fields.
It is written in a language that can be easily understood by anyone not having a background in brewing beer. However, the material is not so elementary that it insults your intelligence, nor is it so difficult that its makes you lose interest in the subject. Clarity is the touchstone that has been employed throughout this book.
Beer the largest alcohol segment nationwide, accounting for roughly 85% of all alcohol volume sold in the United States and annually generating over $91.6 billion in retail sales. The industry has continued to grow and increase its profitability despite economic and flat consumption trends. The beer market is the most concentrated of the three alcohol sectors with three brewers—Anheuser-Busch, South African Breweries’ Miller (SAB-Miller), and Molson Coors Brewing Company—accounting for about 79% all beer sales. Expanded market share, price increases and improved production efficiencies are the keys to improving operating margins for large national brewers in the U.S. beer market. Although there are still some traditional regional brewers that continue to operate, they continue to decline in numbers, often closing or being sold to a larger national brewer. After going through several decades of brewery consolidation, a number of pioneering brewers in the 1980s started producing traditional more full-flavored “craft” beers using only traditional ingredients and brewing practices.
Barley malt is to beer as grapes are to wine. It is ideally suited to brewing for many reasons. Malted barley has a high complement of enzymes for converting its starch supply into simple sugars and contains protein, which is needed for yeast nutrition. Other grains, such as wheat and rye can be malted and used to brew beer too, but they are not widely used.
Hops, a minor ingredient in beer, are used for their bittering, flavoring, and aroma-enhancing powers. Hops also have pronounced bacteriostatic activity that inhibits the growth of Gram-positive bacteria in the finished beer. Hops, when in high enough concentrations, aids in the precipitation of the more water-insoluble proteins in the kettle.
Yeast is one of the most important ingredients in brewing beer responsible for metabolic processes that produce ethanol, carbon dioxide, and a whole range of other metabolic byproducts that contribute to the flavor and finish of beer. There are literally hundreds of varieties and strains of yeast. In the past, there were two types of beer yeast: ale yeast (the “top-fermenting” type, Saccharomyces cerevisiae) and lager yeast (the “bottom-fermenting” type, Saccharomyces pastorianus, formerly referred to as Saccharomyces carlsbergensis or Saccharomyces uvarum). Top fermenting yeasts produce beers that are more estery, fruity, and sometimes malty, whereas bottom-fermenting yeasts give beers a characteristic sulphurous aroma. Some other notable differences also include fermentation temperatures and flocculation characteristics. Top-fermenting yeasts are used for brewing ales, porters, stouts, Altbier, Kölsch while bottom-fermenting yeasts are used for brewing lagers such as Pilsners, Dortmunders, Märzen, and Bocks are fermented with bottom-fermenting yeasts.
Nowadays, the differentiation in ale and lager yeasts is not as distinct given the fact that beers are widely fermented in similar vessels (cylindroconical tanks) and because of other advances in brewing science.
High consumption of good-quality water is characteristic of beer brewing. More than 90% of beer is water and an efficient brewery will typically use between 4 and 6 liters of water to produce one liter of beer. Some breweries use much more water, especially small breweries. In addition to water used for beer production—mashing, boiling, sparging, filtration, and packaging—breweries also use water for heating and cooling as well as cleaning and sanitation of equipment and process areas. Each uses requires a somewhat different water quality too.
Adjuncts are nothing more than unmalted grains such as corn, rice, rye, oats, barley, and wheat. Adjuncts are used mainly because they provide extract at a lower cost (a cheaper form of carbohydrate) than is available from malted barley or to modify the flavor of the beer. Adjuncts are used to produce light-tasting, light-colored beers that have the alcoholic strength of most beers.
Cleaning and sanitation are an integral part of a brewery and should be taken into consideration at every phase of the beer brewing process. Cleaning proceeds sanitation and prepares the way for sanitation treatment by removing organic/inorganic residues and microorganisms from the brewery equipment. Sanitation reduces the surface population of viable microorganisms after cleaning and prevents microbial growth on the brewery equipment.
The objective of milling is to reduce the malt to particles sizes, which will yield the most economic extract (wort) and will operate satisfactorily under brewhouse conditions and throughout the brewing process. The more extensive the malt is milled, the greater the extract production. However, the fine grind can lead to subsequent wort separation problems and a loss of extract in the spent grains during wort separation. As a result, the brewer needs to consider the equipment used in the brewhouse when determining the particle size when milling the malt. For example, mash tuns require comparatively coarse grists while lauter tuns can use finer grists and mash filters still finer grists.
Mashing involves mixing milled malt and solid adjuncts (if used) with water at a set temperature and volume to continue the biochemical changes initiated during the malting process. The malt and adjunct particles swell, starches gelatinize, soluble materials dissolve, and enzymes actively convert the starches to fermentable sugars. The end result is wort with a fixed gravity (OG), a set ratio of fermentable and non-fermentable sugars, and proteins (soluble and non soluble) that affect physical and biochemical changes during fermentation. The composition of the wort will vary according to the style of beer.
After mashing, when the starch has been broken down, the next step is to separate the liquid extract (the wort) from the residual undissolved solid materials found in the mash. Wort separation is important because the solids contain large amounts of protein, poorly modified starch, fatty material, silicates, and polyphenols (tannins).
Following wort separation and extraction of the carbohydrates, proteins, and yeast nutrients from the mash, the clear wort must be conditioned by boiling in the kettle. This chapter covers the biochemical changes that occur during wort boiling, the types of kettle additives, hop and trub removal as well as the types of wort boiling systems used in brewing beer.
After hot trub separation, the wort is preferably cooled to a temperature of 5 to 15°C for bottom-fermented beers and to 15 to 18°C for top-fermented beers (pitching temperature). The wort is then aerated in preparation for the addition of yeast and subsequent fermentation.
Fermentation is the process by which fermentable carbohydrates are converted by yeast into alcohol, carbon dioxide, and numerous other byproducts. It is these byproducts that have a considerable effect on the taste, aroma, and other properties that characterize the style of beer.
Following primary fermentation, the “green” or immature beer is far from finished because it contains suspended particles, lacks sufficient carbonation, lacks taste and aroma, and it is physically and microbiologically unstable. Conditioning reduces the levels of these undesirable compounds to produce a more finished product.
Although conditioning-maturation, clarification, and stabilization-plays an important role in reducing yeast and haze loading materials, a final filtration is needed in order to achieve colloidal and microbiological stability. The beer must be rendered stable so that visible changes do not occur during its shelf life.
The next major process that takes place after filtration and prior to packaging is carbonation. Carbon dioxide not only contributes to perceived “fullness” or “body” and enhances foaming potential it also acts as a flavor enhancer and plays an important role in extending the shelf life of the product.
The level of dissolved carbon dioxide in beer following primary fermentation varies as a result of a number of parameters such as temperature, pressure, yeast, type of fermentation vessel, and initial wort clarity. Typically, carbon dioxide levels range from 1.2 to 1.7 volumes of carbon dioxide per volume of beer (v/v) for non-pressurized fermentations. Consequently, carbon dioxide levels need adjustment, unless the beer has undergone secondary fermentation. Common practice is to raise the carbon dioxide level between 2.2 and 2.8 v/v and possibly more prior for bottled and canned products. The carbon dioxide levels for kegged beer typically range from 1.5 to 2.5 volumes (2).
Once the final quality of the beer has been achieved, it is ready for bottling. The bottling of beer is one of the most complex aspects of brewery operations and the most labor intensive of the entire production process. The layout of the bottling line will depend on a number of factors but typically consists of a series of processes as shown below if non-returnable bottles are used.
If returnable bottles are used it will also include the following processes: depalletzing, decrating, bottle washing, bottle rinsing, and empty bottle inspection. These processes will not be discussed since non-returnable bottles are mainly used in the U.S. and European markets.
Kegs, another option in packaging beer, are used in bars and catering establishments where beer is served “on draught.” Kegging involves filling carbonated pasteurized beer into sterile aluminum or stainless steel kegs of various sizes. Aluminum kegs are generally more popular than stainless steel kegs because they are lighter and more resistant to minor damage. Kegging fits into the cost structure for craft brewers with limited startup capital for bottling lines and low product output.
Microbial contamination can originate from a variety of sources in the brewing process. Raw materials, air, brewing water, additives, and even pitching yeast can act as a constant supply of contaminants. Residues remaining in brewhouse tanks, pipelines, valves, heat exchangers, and packaging equipment harbor microorganisms too that represent a potential source of recontamination. Some of the effects of contamination range from comparatively minor changes in beer flavor and fermentation performance to gross flavor and aroma defects, turbidity problems, abnormal attenuation rates, and reduced yeast crops.
The beer brewing process generates large amounts of wastewater effluent and solid wastes that must be disposed of or treated in the least costly way to meet strict discharge regulations set by government entities.
Brewery wastewater typically has a high biochemical oxygen demand (BOD) from all the organic components (sugars, soluble starch, ethanol, volatile fatty acids, etc). Brewery wastewater usually has temperatures ranging from 25°C to 38°C. The pH levels can range between 2 and 12 and are influenced by the amount and type of chemicals used in cleaning and sanitation (e.g., caustic soda, phosphoric acid, nitric acid, etc.). Nitrogen and phosphorus levels are mainly dependent on the raw material and the amount of yeast present in the effluent.
Although beers are brewed from similar materials, beers throughout the world have distinctive styles. Their uniqueness comes from the mineral content of the water used, the types of ingredients employed, and the difference in brewing methods. In a strict sense, there are two classical beer styles—ales and lagers. However, in addition to ales and lagers, there are other classical beer styles such as wheat beers, porters, stouts, and lambics—to name a few—that merit differentiation.
Traditionally, ales are most associated with Britain, Ireland, and Scotland. British variations include mild, bitter, and pale ales; India Pale Ale; brown ale; old ale; and barley wines. Today, ales are produced throughout the world. The ale family also includes Belgian specialty beers, German specialty beers, and American ales. Ales tend to have a fruity aroma and palate, and often a complex flavor varying considerably among ales in bitterness, color, sweetness, and harshness.
The brewing industry is subject to extensive government regulations at both the federal and state levels, as well as to regulation by a variety of local governments. Some of the regulations imposed at the federal and state level involve production, distribution, labeling, advertising, trade and pricing practices, credit, container characteristics, and alcoholic content. Federal, state and local governmental entities also levy various taxes, license fees and other similar charges and may require bonds to ensure compliance with applicable laws and regulations. Specific alcohol taxation (as opposed to more general sales taxes) is primarily a federal and state right although some states permit some additional local taxation. The brewing industry must also comply with numerous federal, state, and local environmental protection laws.