Brewing begins with malted barley, which is the sprouted, then dried and/or roasted, barley seed. The malt is coarsely crushed and mixed with hot water to form a mash. During the mash, compositional changes occur, brought about by enzymes in the malt. The hot aqueous solution leaches the contents out of the crushed malt kernels and gelatinizes the starch; the enzymes reduce them to soluble fractions. This extract is rinsed from the insoluble malt particles during sparging. The sweet solution is called wort.
The wort is boiled with the flowerlike cone of the hop vine for bitterness and flavor, and to clarify the wort. The wort is cooled, and active brewers’ yeast is added to ferment it. The yeast forms carbon dioxide and alcohol from the sugars extracted from the malt; carbon dioxide carbonates the beer. This fermentation may be carried out in several stages, and the beer moved from one vessel to another to separate it from flavor-impairing sedimented yeast, malt, and hop residues.
The beer is bottled, kegged, or casked so that it may be served carbonated.
The volume, temperature, and density (weight) of a solution all have various terms by which they may be expressed. Throughout this book, U.S. gallons, degrees Fahrenheit, and density as degrees Plato have been given, with liters, degrees centigrade, and specific gravity parenthetically appended. The term original gravity (OG) refers to the density of the boiled wort (original extract, OE), and final gravity (FG) to the density of the fermented beer (apparent extract, AE). Specific gravity (sp gr) refers to the usual metric system (sp gr 1.046), gravity (SG) to a simpler form of expression preferred by brewers (1046), and excess gravity (G) to an abbreviated form (46) commonly used in equations.
Other abbreviations used in this book include:
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ASBC |
American Society of Brewing Chemists |
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EBC |
European Brewing Convention |
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IOB |
Institute of Brewing (British) |
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°F |
Temperature, degrees Fahrenheit |
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°C |
Temperature, degrees Centigrade |
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°Plato |
Density, degrees Plato |
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°SRM |
Wort color, standard reference method |
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°L |
Malt color, degrees Lovibond (often used interchangeably with SRM) |
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°HCU |
Homebrew color units (sum of °L of goods) |
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°EBC |
Color, degrees EBC |
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°IOB |
Color, degrees IOB |
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DBFG |
Laboratory extract potential, dry basis fine grind |
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DBCG |
Brewhouse extract potential, dry basis coarse grind |
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FG-CG |
Malt modification, fine grind minus coarse grind |
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HWE |
Hot water extract, extract potential, IOB method |
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CWE |
Cold water extract, modification, IOB method |
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TN |
Total nitrogen |
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% P |
Percent protein (TN/6.25) |
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Total soluble nitrogen |
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SNR |
Soluble nitrogen ratio (TSN/TN) |
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DP |
Diastatic power |
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IBU |
International bittering units, iso-alpha acid in solution |
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BU |
Bittering unit (IBU x 1.125) |
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HBU |
Homebrew bitterness units, identical to AAU (alpha acid units, ounces of hops x % alpha acid) |
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DU |
Dextrinizing units |
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MC |
Moisture Content |
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Ppm |
Parts per million |
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mg/L |
Milligrams per liter |
For those more familiar with standards other than those used herein, tables are provided in appendix D for conversion of U.S. standards to metric and British units. Other useful tables of measure and conversion formulas for brewing are also found in the appendixes.
The range of lager beers is represented by seven recognized types, which are identified by the brewing centers where they evolved. They are:
Pilsener (Pilsner, Pils), Bohemia, Czech Republic. 11 to 14 °Plato (OG 1044 to 1057). Golden color, distinctive hop palate, medium body, well carbonated, dry. 4 to 5.2 percent alcohol by volume (3.2 to 4.1 w/w). After the style set by the classic Pilsner Urquell (Plzensky Prazdroj). Served at 48 to 50 degrees F (9 to 10 degrees C).
Dortmunder (Dort, Export), Westfalen, Germany. 12 to 14 °Plato (OG 1049 to 1057). Light, golden-blond color, moderate hop palate, medium body; rich, mellow, and yet sharp. 5 to 5.7 percent alcohol by volume (3.9 to 4.5 w/w). Served at 48 to 50 degrees F (9 to 10 degrees C).
Vienna (Wiener/Spezial, Märzenbier/Oktoberfest), Lower Austria and Bavaria. 12.5 to 15 °Plato (OG 1050 to 1061). Reddish-amber or copper color, moderately hopped, medium body; malt to toasted-malt flavor. Viennas tend to be somewhat drier and more bitter than Oktoberfests. 4.9 to 5.7 percent alcohol by volume (3.8 to 4.5 w/w). Served at 50 to 55 degrees F (10 to 13 degrees C).
Dark Munich (Münchener dunkel), Bavaria, Germany. 12 to 14 °Plato (OG 1048 to 1057). Dark-brown color, lightly hopped, medium to full body; slightly sweet, malty flavor. 4.5 to 5.5 percent alcohol by volume (3.5 to 4.3 w/w). Served at 35 to 45 degrees F (2 to 7 degrees C).
Light Munich (Münchener helles), Bavaria, Germany. 11 to 12 °Plato (OG 1044 to 1049). Amber color, lightly hopped, medium bodied; slightly sweet, malty character. 4 to 5 percent alcohol by volume (3.2 to 3.9 w/w). Served at 45 to 50 degrees F (7 to 10 degrees C).
Bock, Bavaria, Germany. 16 to 18 °Plato (OG 1065 to 1074). Light- to dark-brown color, rich and malty flavor, medium to full body. Darker bocks usually have a roasted-malt and hop flavor. 6 to 7.5 percent alcohol by volume (4.7 to 5.9 w/w). Served at 50 to 65 degrees F (10 to 18 degrees C).
Dopplebock, Bavaria, Germany. Most often the brand name ends in the suffix -ator. 18 to 28 °Plato (OG 1074 to 1112). Light- to dark-brown color, often having a roasted-malt flavor. Medium to very full bodied. 7.5 to 13 percent alcohol by volume (5.9 to 10.2 w/w). Served at 50 to 65 degrees F (10 to 18 degrees C).
Myriad variations of the classic lager types exist: eisbocks that are partially frozen to increase the concentration of alcohol; schwarzpils and dark Pilseners, some with and some without roast-malt character; smoked lagers; spiced lagers; and American Pilseners, the much-maligned fizz-water that many Americans still think is the only kind of beer.
Lagers are defined by the process used to brew them. They are essentially distinguished from ales, the other beer family, by relatively slower fermentation at cool (40 to 55 degrees F [4 to 13 degrees C]) temperatures, followed by a relatively longer period of cold conditioning. By definition, lagers have low levels of esters and vicinal diketones; devoid of significant “yeast character,” they rely solely upon the interplay of the malt, hops, and water for their aromas and flavors.