BREWING MICROBIOLOGY, THIRD EDITION Brewing Microbiology Third edition Edited bụ Fergus G. Priest and lain Campbell International Centre for Brewing and Distilling Heriot-Watt University Edinburgh, UK Library of Congress Cataloging-in-Publication Data Brewing microbiology / [edited by] Fergus G. Priest and Jain Campbell—3rd ed. Includes bibliographical references and index.
ISBN 978-1-4613-4858-0 ISBN 978-1-4419-9250-5 (eBook) DOI 10. Campbell, Iain QR151 B75 2002 663'3—dc21 2002072695 © 2003 Springer Science+Business Media New York Originally published by Kluwer Academic/Plenum Publishers New York in 2003 Softcover reprint of the hardcover 3rd edition 2003 10987654321 AC. record for this book is available from the Library of Congress. All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for the exclusive use by the purchaser of the work Contents List of contributors Preface 1 Microbiological aspects of brewing Iain Campbell 1.3 Brewing, mashing, and hop boiling 14 Fermentation 15 Postfermentation treatments 1.6 Concluding remarks References The biochemistry and physiology of yeast growth J.2 The cell cycle 19 2.3 The growth and fermentation cycle 20 24 Cell composition, nutrition, and general metabolism 21 2.5 Energy and intermediary metabolism 21 2.6 Yeast biochemistry and beer production 32 27 Summary References 62 Yeast genetics 67 John R.2 Genetic features of Saccharomyces cerevisiae 3.
The need for new brewing yeasts 72 3.4 Genetic techniques 73 vi Contents 3.5 Application of recombinant DNA methods to brewing yeasts 81 3.6 Molecular biological approaches to yeast differentiation 98 3.7 The nature of the brewing yeast genome 101 3.8 The commercial use of genetically modified brewing yeasts 104 3.9 Conclusions 105 Acknowledgment 105 References 106 The microbiota of barley and malt 113 Brian Flannigan 41 The microbiota of barley 113 42 The microbiota of malt 133 43 Effects of microorganisms on malting 142 44 Effects of the microbiota on beer and distilled spirit 151 45 Health hazards 156 46 Assessment of mold contamination 166 References 172 Gram-positive brewery bacteria 181 Fergus G. Priest 51 Introduction 181 Lactic acid bacteria 182 Lactobacillus 190 Pediococcus 202 Leuconostoc 207 Homofermentative cocci 207 Kocuria, Micrococcus and Staphylococcus 209 Endospore-forming bacteria 210 Identification of genera of Gram-positive bacteria of brewery origin 210 5.10 Concluding remarks 212 References 212 Gram-negative brewery bacteria 219 Hennie J. Van Vuuren and Fergus G.5 Anaerobic Gram-negative rods 235 6.7 Miscellaneous non-fermentative bacteria 238 6.8 Detection, enumeration, and isolation 238 6.9 Conclusions 241 References 242 Contents vii 7 Wild yeasts in brewing and distilling 247 Iain Campbell 71 Introduction 247 72 Systematics of yeasts 247 73 Properties for identification of yeasts 251 74 Detection of wild yeasts 255 75 Identification of wild yeasts 257 76 Effects of wild yeasts in the brewery 259 77 Elimination of wild yeasts 263 References 8 Rapid detection and identification of microbial spoilage 267 Inge Russell and Robert Stewart 8.8 Direct epiflourescence filter technique (DEFT) 284 8.10 Protein fingerprinting by polyacrylamide gel electrophoresis 287 8.13 Hybridization using DNA probes 292 8.14 Polymerase chain reaction 294 8.15 Random amplified polymorphic DNA PCR 297 8.16 Summary 297 Acknowledgments 298 References 298 9 Rapid identification of microorganisms 305 Fergus G.1 What is identification? 305 9.2 Approaches to identification 306 93 Nucleic acid-based identification 307 9.4 Techniques for examining proteins 318 9.5 Methods that examine aspects of cell composition 319 9.6 Techniques for studying morphology and behavior 97 Concluding remarks 325 Acknowledgments 326 References 326 viii Contents 10 Microbiology and sanitation in U.2 The raw materials 329 10. The process and product 332 10.4 Beer contact surfaces 333 10.5 Concluding remarks 335 References 335 11 Cleaning and disinfection in the brewing industry 337 Manjit Singh and Jacqueline Fisher 111 Introduction 337 112 Definitions 337 11.
Standards required in a brewery 338 114 Cleaning methods available 341 11.6 Process of detergency 346 117 Chemistry of detergents 346 11.8 Caustic and alkaline detergents 347 119 Sequestrants 1110 Acids 351 1111 Surface-active agents 353 11.12 Disinfectants and sanitizers used in breweries 355 11.13 Oxidizing disinfectants 356 1114 Nonoxidizing disinfectants 360 11.16 Steam 365 1117 Summary 365 References 366 12 Microbiological methods in brewing analysis 367 Iain Campbell 12.2 Microbiological analysis of raw materials 368 123 Yeast 375 124 Wort and fermentation 382 12.5 Sterility of plant 383 12.6 Beer 387 127 Conclusions 391 References 392 Index 393 Contributors Iain Campbell* International Centre for Brewing and Distilling, Heriot- Watt University, Edinburgh EH14 4AS, UK Jacqueline Fisher* Diversey Lever, Weston Favell Centre, Northampton, NN3 8PD, UK Brian Flannigan BioForce Associates, 3 Merchiston Avenue, Edinburgh EH10 4NT, UK John R. Hammond BRF International, Lyttel Hall, Coopers Hill Road, Nutfield, Surrey, RH1 4HY, UK Michael J. Lewis University of California Academic Director of Brewing Programs, University Extension, Davis, California 95616, USA Fergus G. Priest International Centre for Brewing and Distilling, Heriot- Watt University, Edinburgh EH14 4AS, UK Inge Russel* 467 Commissioners Road E., London, Ontario, Canada N6C 276 Manjit Singh* Diversey Lever, Weston Favell Centre, Northampton, NN3 8PD, UK J.
Colin Slaughter International Centre for Brewing and Distilling, Heriot- Watt University, Edinburgh EH14 4AS, UK Robert Stewart Labatt Breweries of Canada, Research and Technical Services Department, 150 Simcoe Street, London, Ontario, Canada N6A 4M3 Hennie J. van Vuuren Food, Nutrition and Health, Faculty of Agricultural Sciences, The University of British Columbia, Vancouver, B. Canada V6T 1Z4 *Retired or changed address recently Preface Much has happened in the brewing industry since the last edition of this book was published in 1996. In particular, there has been substantial con- solidation of larger brewing companies as major multinational concerns, and at the other end of the spectrum the microbrewing scene in various parts of the world has become established as a sustainable enterprise.
For those involved in the scientific and technical aspects of fermented bever- age production the changes have been no less daunting. The complete genome sequence of Saccharomyces cerevisiae has been determined and studies are underway in numerous laboratories throughout the world to unravel the expression of the genome (transcriptomics and proteomics) and understand exactly “how a yeast works.” This will undoubtedly con- tribute to our understanding of yeast fermentation and flavor generation in a revolutionary way because it will enable the simultaneous monitor- ing of all genes in the organism during the fermentation. In Chapters 2 and 3 of this volume Colin Slaughter and John Hammond bring the reader up-to-date in this rapidly moving area and cover the remarkable achievements of modern biochemistry and molecular biology. Iain Campbell has also revised the systematics of culture and wild yeasts in Chapter 7.
The other major technical change since the last edition of this book is the introduction of molecular characterization and detection of microor- ganisms based largely, but not exclusively, on the polymerase chain reac- tion (PCR) for amplification of specific DNA fragments. Although few of these methods are yet used routinely in the brewery laboratory, the speed, accuracy, and scope that they offer are immensely attractive, and it is likely that as they become more automated and less expensive they will be incorporated into quality-assurance procedures. In addition to describ- ing these exciting developments, we have also included new chapters covering the role of microbiology in the brewing process and, in particu- xii Preface Jar in the microbrewery, as well as a chapter devoted to the rationale behind microbiological analyses used in the brewery. We are grateful to Brian Flannigan for revising his definitive account of the microorganisms associated with barley and malt and finally, we thank Annie Hill for assis- tance with preparation of diagrams.
Brewing microbiology has a long and prominent history. We hope that the third edition of this book will persuade the reader that there is still much to learn of this ancient art. Fergus G Priest, Iain Campbell (ICBD, Edinburgh) CHAPTER1 Microbiological aspects of brewing Iain Campbell 1.1 INTRODUCTION Not only are there microbiological aspects of brewing, one could argue that the science of microbiology developed from brewing. Louis Pasteur’s assistance with a problem of beer spoilage was an important stage in the development of modern microbiology.
Brewing is essentially a combination of engineering with botany, bio- chemistry, chemistry, and microbiology. Archaeological evidence indicates that beer has been produced since before 4000 BC (Moll, 1994), but the microbiological nature of the process has been understood only for the past 150 years. The application of microbiology to optimize the process in terms of efficiency and quality is of even more recent date. There are two principal aspects to brewing microbiology: (a) the quality of the culture yeast itself, and (b) the control of various possible microbial contaminants.
The specialized chapters later in this book provide a full explanation of the various microbiological aspects of beer production, but this brief intro- ductory chapter is intended to provide a microbiological overview of the production of alcoholic beverages, and beer in particular. For information on other, nonmicrobiological aspects of brewing the reader is referred to general texts, e. by Moll (1994), Hardwick (1995), or Lewis and Young (1995), but a general outline of the process is provided as Fig. In most countries, barley malt is an obligatory ingredient of beer and represents a distinct environment with its own varied microbial flora (Chapter 4).
The great majority of these microorganisms are unable to grow in beer under normal circumstances. Most fungi and bacteria are suppressed by one or more of the following effects: (a) the antimicrobial properties of hops, (b) falling pH during fermentation, from 5.2 in Brewing Microbiology, 3rd edn. Published in 2003 by Kluwer Academic/Plenum Publishers, New York. ISBN 0-306-47288-0 2 Microbiological aspects of brewing MALTING Modification of barley starch (preparation for hydrolysis in the mash tun) Hydrolysis of protein => free amino nitrogen Structural alteration to more friable consistency MILLING, MASHING Milling to suitable particle size range Enzymic hydrolysis and extraction of sugars, amino acids, other yeast nutrients and enzymes with hot water => sweet wort WORT BOILING Boiling with hops to extract aroma and bittering compounds => hopped wort Sterilization FERMENTATION Conversion by yeast (Saccharomyces cerevisiae) of fermentable sugars to ethanol + CO, Production of flavor compounds, by-products of yeast metabolism Purging of unwanted volatiles (e.
H;S) by evolution of CO, POST-FERMENTATION TREATMENTS Maturation (improvement of flavor) Clarification Packaging Pasteurization Fig.1 Outline of the brewing process.0 in beer, (c) developing CO; and anaerobic conditions, and (d) increasing ethanol content. Lacking most of these protective effects, wort is highly susceptible to spoilage and must be pitched with culture yeast immediately after collection, or better still, during collection. Even before fermentation gets properly under way, a small number of contam- inant bacteria in wort would be swamped by the enormous excess of pitching yeast. Beer, with its intrinsic antimicrobial properties and a low level of residual fermentable sugar, is relatively stable but liable to spoilage by the few specialized types of bacteria and yeasts capable of growing anaerobically on the complex polysaccharides or other organic compounds still present after fermentation (Hammond, Brennan & Price, 1999).
So, although malt carries only small numbers of the lactic and acetic acid bacteria and enterobacteria shown in Table 1.1, these are a likely source of contamination of wort or beer when a combination of other fac- tors favors the growth of these organisms. A wider range of contaminants is possible in unhopped or low-alcohol beers, each of which lacks one of the protective effects of normal beer.1 also shows aerobic con- taminants, i. oxidative yeasts and acetic bacteria, as contaminants of beer. However, these organisms can flourish only as a result of a packag- ing fault allowing access of atmospheric oxygen to the head space of the container.1 Occurrence of microbial contaminants of the brewing industry 8 Hs Stage : § Š Ễ 2 bì3 kìH i a 2EÌ a 2 2 2 .