Applied Malting and Brewing Science

Ludwig Narziß was Professor at the Chair for Brewing Technology at the TU Munich, Freising-Weihenstephan, Germany, until his retirement in 1992. He is renowned as having been one of the world’s leading experts in malting and brewing science. He published frequently on a broad range of topics over many years and remained active in the industry until his passing in December of 2022. Werner Back succeeded Ludwig Narziß as Professor of Brewing Technology at the TU Munich, Freising-Weihenstephan, Germany. He is likewise a well-respected and widely published author on malting and brewing science and technology. Martina Gastl is Professor of Brewing Technology and Director of the Research Center Weihenstephan for Brewing and Food Quality, TU Munich, Freising-Weihenstephan, Germany. Martin Zarnkow leads the R&D department at the Research Center Weihenstephan for Brewing and Food Quality, TU Munich, Freising-Weihenstephan, Germany.

• A Few Words of Thanks ixPreface xi1 The Technology of Malting 11.1 Malting Barley 11.1.1 The Morphology of Barley 21.1.2 The Chemical Composition of Barley 21.1.3 Determining and Evaluating the Properties of Barley 61.2 Preparing Barley for Malting 91.2.1 Receiving Barley in Bulk 91.2.2 Conveyor Systems 91.2.3 Cleaning and Sorting Barley 101.2.4 Preparing and Storing Barley 131.2.5 Artificial Drying of Barley 161.2.6 Plant Diseases and Animal Pests Affecting Barley 181.2.7 Changes in the Weight of Barley During Storage 191.3 Steeping the Barley 191.3.1 Moisture Uptake in the Barley Kernel 191.3.2 Supplying Oxygen to the Steeping Grain 201.3.3 Cleaning the Barley 211.3.4 Water Consumption 211.3.5 Steeping Equipment 221.3.6 Steeping Technology 251.4 Germination 281.4.1 The Theory of Germination 281.4.2 The Practice of Germination 361.5 Various Malting Systems 411.5.1 Floor Malting 411.5.2 Pneumatic Malting Systems 451.5.3 Germination Vessels in Pneumatic Malting Systems 491.5.4 The Finished Green Malt 651.6 Kilning the Green Malt 661.6.1 The Processes Involved in Kilning 661.6.2 Kilns 721.6.3 Kilning Techniques 791.6.4 Monitoring and Automating Kilning – Kiln Maintenance 871.6.5 Energy-Saving Measures 881.6.6 Additional Tasks Associated with Kilning 891.6.7 Handling of Malt After Kilning 901.6.8 Storing Malt and Maintaining Malt Stores 911.7 Malting Losses 921.7.1 Losses During Steeping 931.7.2 Losses During Respiration and Germination 931.7.3 Calculating Malting Losses 941.8 The Properties of Malt 951.8.1 External Characteristics 951.8.2 Mechanical Analysis 951.8.3 Physico-Chemical Analysis 961.9 Malt from Other Grains 981.9.1 Wheat Malt 981.9.2 Malt from Alternative Cereals 1001.9.3 Pseudocereals 1031.9.4 Specialty Malts 1031.9.5 Micromalting 1062 The Technology of Wort Production 1092.1 Raw Materials for the Brewing Process 1092.1.1 Malt 1092.1.2 Adjuncts: Alternatives to Malt 1092.1.3 Brewing Liquor 1112.1.4 Hops 1242.1.5 Adding Hops to the Wort 1392.2 Milling the Malt 1482.2.1 Monitoring Grist Quality 1502.2.2 Mill Designs 1502.2.3 Properties and Composition of the Grist 1582.2.4 The Arrangement of the Milling Area 1592.3 Wort Production 1592.3.1 The Theory of Mashing 1592.3.2 Mashing Techniques 1682.3.3 Mashing Regimes 1742.3.4 Particular Issues with Mashing 1852.3.5 Monitoring the Mashing Process 1862.4 Extracting the Wort (Lautering) 1882.4.1 Operations During Lautering 1882.4.2 The Lauter Tun 1892.4.3 The Lautering Process with a Lauter Tun 1922.4.4 Lautering with a Conventional Mash Filter 2022.4.5 Membrane Compression Filters 2032.4.6 The Thin-bed Filter 2052.4.7 A Comparison of Thin-bed Mash Filtration and the Modern Lauter Tun 2072.4.8 The Strainmaster 2072.4.9 Continuous Lautering Methods 2082.4.10 The Wort Collection Vessel 2092.5 Boiling and Hopping the Wort 2092.5.1 Wort Kettles 2102.5.2 Physical Processes During Wort Boiling 2152.5.3 Coagulation of Protein 2162.5.4 Hopping the Wort 2192.5.5 Aroma Compounds in Wort 2262.5.6 Technical and Energy Aspects of Modern Wort Boiling Systems 2292.5.7 Casting Out the Wort 2362.5.8 The Cast-out Wort 2372.5.9 Cleaning the Brewhouse Equipment 2372.5.10 Automating the Wort Boiling Process 2392.5.11 Options for Recovering Residual Extract 2392.5.12 Spent Grain 2412.5.13 Safety and Consistency in the Brewhouse Production 2412.6 Brewhouse Yield 2422.6.1 Calculation of Brewhouse Yield 2422.6.2 Assessing Brewhouse Yield 2442.6.3 Conclusions on the Topic of Brewhouse Yield 2462.7 Wort Chilling and Elimination of Break Material 2462.7.1 Chilling the Wort 2472.7.2 Oxygen Uptake in the Wort 2472.7.3 Elimination of Hot and Cold Break Material 2472.7.4 Other Processes 2492.7.5 Wort Chilling and Cold Wort Handling 2492.7.6 Operations with a Coolship and a Baudelot (Falling Film) Chiller or a Closed Chiller 2492.7.7 Closed Wort Chilling Systems 2512.8 Cold Wort Yield 2602.8.1 Data Collected for Cold Wort Yield 2602.8.2 Calculation of Cold Wort Yield 2602.8.3 Overall Yield in Wort Production (Overall Brewhouse Yield – OBY) 2613 The Technology of Fermentation 2633.1 Brewing Yeast 2633.1.1 Yeast Morphology 2633.1.2 The Chemical Composition of Yeast 2643.1.3 Yeast Enzymes 2643.1.4 Yeast Reproduction 2653.1.5 Yeast Genetics 2663.1.6 Genetic Manipulation of Yeast 2663.1.7 Yeast Autolysis 2683.2 Yeast Metabolism 2683.2.1 Carbohydrate Metabolism 2693.2.2 Protein Metabolism 2713.2.3 Lipid Metabolism 2723.2.4 Mineral Metabolism 2733.2.5 Vitamins 2743.2.6 Metabolites and Their Significance for Beer Quality 2743.3 Bottom-fermenting Yeast in Brewing Operations 2793.3.1 Yeast Strain Selection 2793.3.2 Culturing Pure Strains of Brewing Yeasts 2793.3.3 Yeast Degeneration and Loss of Typical Characteristics 2813.3.4 Harvesting Yeast 2823.3.5 Cleaning the Yeast 2833.3.6 Yeast Storage 2843.3.7 Shipping Yeast – Dry Yeast 2853.3.8 The Physiological Condition of the Yeast 2853.4 Beer Production with Bottom-fermenting Yeast 2863.4.1 Fermentation Rooms or Cellars 2863.4.2 Fermentation Vessels 2873.4.3 Pitching the Yeast 2943.4.4 Conducting Fermentation 2973.4.5 Primary Fermentation 2983.4.6 Degree of Attenuation 3013.4.7 Maturation Levels of the Green Beer 3043.4.8 Changes in the Wort During Fermentation 3043.4.9 Recovery of Carbon Dioxide Produced During Fermentation 3073.5 Maturation and Lagering 3093.5.1 The Lager Cellar 3103.5.2 Lager Vessels 3113.5.3 The Maturation Process 3123.6 Modern Fermentation and Lagering Methods in Beer Production 3213.6.1 Methods of Operation for Fermenting in Tanks and Larger Vessels 3213.6.2 Utilization of Intermediate Storage Tanks and Implementation of a Green Beer Centrifuge 3263.6.3 Methods for Accelerating Fermentation and Maturation 3273.6.4 Continuous Fermentation Processes 3353.6.5 Classic CCTs Employed in a Continuous-flow Process 3363.6.6 Hopping Beer on the Cold Side 3364 Beer Filtration 3394.1 The Theory of Filtration 3394.2 Filtration Technology 3414.2.1 Pulp Filtration 3414.2.2 Diatomaceous Earth Filtration 3424.2.3 Sheet Filters 3494.2.4 Membrane Filtration 3504.2.5 Centrifuges 3514.3 Combined Clarification Processes 3534.4 Options for Replacing Diatomaceous Earth as a Filter Medium 3534.4.1 Combining a Centrifuge with a Pulp Filter 3534.4.2 Combining a Fine Clarification Centrifuge and a Horizontal Filter 3544.4.3 Multi-step Microfiltration 3544.4.4 Filter Sheets 3544.4.5 The Use of Synthetic Extrudates 3554.4.6 Crossflow Microfiltration 3554.4.7 Concluding Remarks on Modern Filtration Systems 3594.5 Filtration – Auxiliary Equipment and Monitoring Devices 3594.5.1 Auxiliary Equipment 3604.5.2 Devices for Monitoring Filtration 3604.6 Beginning and Ending a Filtration Run 3614.7 Tank Bottoms 3624.8 Compressed Air 3635 Packaging Beer 3655.1 Beer Storage After Filtration 3655.2 Filling Barrels and Casks 3655.2.1 Barrels and Casks 3655.2.2 Cleaning Barrels and Casks 3665.2.3 Filling Casks and Barrels 3675.2.4 Improvements in Filling and Dispensing from Conventional Casks 3685.2.5 Cleaning and Filling Kegs 3685.2.6 Filling and Storage Areas 3715.3 Bottling and Canning 3715.3.1 The Containers 3715.3.2 Cleaning Bottles 3745.3.3 Bottling 3775.3.4 Cleaning and “Sterilizing” Filling Machines 3825.3.5 Capping the Bottles 3835.3.6 Oxygen Uptake During Bottling 3835.4 “Sterile Filling” and the Pasteurization of Beer 3875.4.1 “Sterile Filling” 3875.4.2 Pasteurization of Beer 3915.5 The Layout of a Bottling Plant 3936 Beer Losses 3956.1 Factors Affecting Beer Losses 3956.1.1 Wort Losses 3966.1.2 True Beer Losses 3976.2 Calculating Beer Losses 3996.2.1 Calculation of Volumetric Losses 3996.2.2 Calculation of Surpluses and Deficits 4006.2.3 Calculating the Quantity of Wort and Beer Obtained from 100 kg of Malt 4006.2.4 Calculating the Extract Losses from the Cast-out Wort and/or from Malt Grist 4006.2.5 The Economic Aspects of Recovering Beer 4017 The Finished Beer 4057.1 The Composition of Beer 4057.1.1 Extract in Beer 4057.1.2 Volatile Compounds 4067.2 The Classification of Beer 4077.3 Properties of Beer 4077.3.1 General Characteristics 4077.3.2 The Redox Potential of Beer 4077.3.3 Beer Color 4087.4 The Aroma of Beer 4087.4.1 Characteristics of Beer Aroma 4097.4.2 Factors Influencing Flavor 4107.4.3 Off-flavors in Beer 4117.5 Beer Foam 4147.5.1 The Theory of Foam Formation 4147.5.2 Technological Influences on the Properties of Beer Foam 4157.6 Factors Affecting the Physico-chemical Properties of Beer and Their Stabilization 4187.6.1 The Composition of Colloidal Turbidity 4187.6.2 The Formation of Colloidal Turbidity 4197.6.3 Technological Measures to Improve Colloidal Stability 4197.6.4 The Stabilization of Beer 4197.6.5 The Flavor Stability of Beer 4287.6.6 Methods for Monitoring and Predicting Flavor Stability 4347.6.7 Turbidity Originating Chemically 4357.6.8 Gushing 4367.7 Filterability of Beer 4387.7.1 The Causes of Poor Filterability in Beer 4387.7.2 Remedial Measures 4407.8 Microbiological Stability of Beer 4417.8.1 Sources of Contamination 4417.8.2 Maintaining Microbiological Shelf Life 4437.9 Physiological Effects of Beer 4457.9.1 The Nutritional Value of Beer 4457.9.2 Dietary Effects of Beer 4467.10 Bottom-fermented German Beer Styles 4467.10.1 Pale Lager Beer (Helles) 4477.10.2 Pale Export (12.5+ %, w/w) 4477.10.3 Pils or Pilsner 4487.10.4 Heller Bock 4487.10.5 Märzen 4497.10.6 Dunkles and Schwarzbier 4497.10.7 German Porter 4507.10.8 Rauchbier or Smoked Beer 4507.11 Special Beers 4517.11.1 Dietetic Beers of the Past 4517.11.2 Nutritive Beers 4537.11.3 Non-alcoholic Beers 4547.11.4 Methods for Limiting Alcohol Content 4547.11.5 Alcohol Removal with Physical Methods 4567.11.6 Combinations of Different Processes in the Production of Non-alcoholic Beer 4597.11.7 Low-alcohol Beers 4618 Top Fermentation 4658.1 General Information 4658.2 Top-fermenting Yeast 4658.2.1 Morphological Characteristics 4658.2.2 Physiological Differences 4668.2.3 Fermentation Attributes 4668.2.4 Yeast Handling 4678.3 Top Fermentation Techniques 4688.3.1 Fermentation Rooms and Fermentation Vessels 4688.3.2 Wort Composition 4708.3.3 Pitching the Yeast 4708.3.4 Primary Fermentation 4708.3.5 Changes in Wort During Top Fermentation 4738.3.6 Maturation 4748.3.7 Filtration and Filling 4768.4 Production Methods for Various Top-fermented German Beers 4778.4.1 Altbier (Düsseldorf and Lower Rhine) 4778.4.2 Kölsch 4798.4.3 Kristallweizen – Filtered Wheat Beer (Free of Yeast) 4808.4.4 Hefeweizen – Bavarian-style Wheat Beer with Yeast 4848.4.5 Top-fermented Beers Brewed with Malted Cereals Other Than Barley and Wheat 4888.4.6 Berliner Weisse 4908.4.7 Other Traditional Top-fermented Beer Styles 4918.4.8 Malzbier 4938.4.9 Bavarian-style, Top-fermented Nutritive Beers 4938.4.10 Top-fermented, Non-alcoholic Beers 4948.4.11 Top-fermented, Low-alcohol Beers 4948.5 Gluten-Free Beer 4948.5.1 Production from Conventional Raw Materials – Genetic Modification of Raw Materials Through Breeding 4948.5.2 Enzymatic Modification of Raw Materials 4948.5.3 Beer Production from Gluten-free Sugar or Starch Sources 4958.5.4 Carbohydrate-rich Cereals and Pseudocereals 4959 High-gravity Brewing 4979.1 High-gravity Wort Production 4979.1.1 Lautering 4979.1.2 Mashing 4979.1.3 Wort Boiling 4979.1.4 Whirlpool Operations 4989.1.5 Dilution of High-gravity Wort at the Chiller 4989.2 Fermentation of High-gravity Wort 4999.3 Dilution of High-gravity Beer After Maturation 4999.4 The Properties of Beer Produced with High-gravity Techniques 500Index 501