.Brewing Science and practice ppt

Brewing
Science and practice
Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and
Roger Stevens
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
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Preface
1Anoutlineofbrewing
1.1Introduction
1.2Malts
1.3Mashtunadjuncts
1.4Brewingliquor
1.5Millingandmashingin
1.6Mashingandwortseparationsystems
1.7Thehop-boilandcopperadjuncts
1.8Wortclarification,coolingandaeration
1.9Fermentation
1.10Theprocessingofbeer
1.11Typesofbeer
1.12Analyticalsystems
1.13Theeconomicsofbrewing

1.14Excise
1.15Referencesandfurtherreading
1.15.1Thesystemsofmaltingandbrewinganalysis
1.15.2Generalreferences
2Malts,adjunctsandsupplementaryenzymes
2.1Gristsandothersourcesofextract
2.2Malting
2.2.1Maltinginoutline
2.2.2Changesoccurringinmaltinggrain
2.2.3Maltingtechnology
2.2.4Maltanalyses
2.2.5Typesofkilnedmalt
2.2.6Specialmalts
Contents
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
2.2.7 Malt specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.3 Adjuncts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.3.1 Mash tun adjuncts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.3.2 Copper adjuncts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.4 Priming sugars, caramels, malt colourants and Farbebier . . . . . . . . . . 45
2.5 Supplementary enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3 Water, effluents and wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.2 Sources of water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.3 Preliminary water treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.4 Secondary water treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.5 Grades of water used in breweries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.6 The effects of ions on the brewing process . . . . . . . . . . . . . . . . . . . . . . . . . 65

3.7 Brewery effluents, wastes and by-products . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.7.1 The characterization of waste water . . . . . . . . . . . . . . . . . . . . . . . . 69
3.7.2 The characteristics of some brewery wastes and
by-products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.8 The disposal of brewery effluents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
3.8.1 Preliminary treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
3.8.2 Aerobic treatments of brewery effluents . . . . . . . . . . . . . . . . . . . 75
3.8.3 Sludge treatments and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
3.8.4 Anaerobic and mixed treatments of brewery effluents . . . . . 79
3.9 Other water treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
3.10 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
4 The science of mashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.2 Mashing schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
4.3 Altering mashing conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
4.3.1 The grist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
4.3.2 Malts in mashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.3.3 Mashing with adjuncts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
4.3.4 The influence of mashing temperatures and times on
wort quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
4.3.5 Non-malt enzymes in mashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.3.6 Mashing liquor and mash pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
4.3.7 Mash thickness, extract yield and wort quality . . . . . . . . . . . . . 116
4.3.8 Wort separation and sparging . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
4.4 Mashing biochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
4.4.1 Wort carbohydrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
4.4.2 Starch degradation in mashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.4.3 Non-starch polysaccharides in mashing . . . . . . . . . . . . . . . . . . . . 136
4.4.4 Proteins, peptides and amino acids . . . . . . . . . . . . . . . . . . . . . . . 142
4.4.5 Nucleic acids and related substances . . . . . . . . . . . . . . . . . . . . . . . 146

4.4.6 Miscellaneous substances containing nitrogen . . . . . . . . . . . . . . 146
4.4.7 Vitamins and yeast growth factors . . . . . . . . . . . . . . . . . . . . . . . 149
4.4.8 Lipids in mashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
vi Contents
4.4.9Phenols
4.4.10Miscellaneousacids
4.4.11Inorganicionsinsweetwort
4.5Mashingandbeerflavour
4.6Spentgrains
4.7References
5Thepreparationofgrists
5.1Intake,handlingandstorageofrawmaterials
5.2Theprinciplesofmilling
5.3Laboratorymills
5.4Dryrollermilling
5.5Impactmills
5.6Conditioneddrymilling
5.7Spraysteeprollermilling
5.8Steepconditioning
5.9Millingunderwater
5.10Gristcases
5.11References
6Mashingtechnology
6.1Introduction
6.2Mashingin
6.3Themashtun
6.3.1Construction
6.3.2Mashtunoperations
6.4Mashingvesselsfordecoction,doublemashingandtemperature-
programmedinfusionmashingsystems

6.4.1Decoctionanddoublemashing
6.4.2Temperature-programmedinfusionmashing
6.5Lautertuns
6.6TheStrainmaster
6.7Mashfilters
6.8Thechoiceofmashingandwortseparationsystems
6.9Othermethodsofwortseparationandmashing
6.10Spentgrains
6.11Theoryofwortseparation
6.12References
7Hops
7.1Introduction
7.2Botany
7.3Cultivation
7.4Drying
7.5Hopproducts
7.5.1Hoppellets
7.5.2Hopextracts
7.5.3Hopoils
7.6Pestsanddiseases
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
7.6.1Damson-hopaphid
7.6.2(Red)SpiderMite
7.6.3Otherpests
7.6.4Downymildew
7.6.5Powderymildew
7.6.6Verticilliumwilt
7.6.7Virusdiseases
7.7Hopvarieties
7.8References

8Thechemistryofhopconstituents
8.1Introduction
8.2Hopresins
8.2.1Introduction
8.2.2Biosynthesisofthehopresins
8.2.3Analysisofthehopresins
8.2.4Isomerizationofthe-acids
8.2.5Hardresinsandprenylflavonoids
8.2.6Oxidationofthehopresins
8.3Hopoil
8.3.1Introduction
8.3.2Hydrocarbons
8.3.3Oxygen-containingcomponents
8.3.4Sulphur-containingcompounds
8.3.5Mostpotentodorantsinhopoil
8.3.6Hopoilconstituentsinbeer
8.3.7Postfermentationaromaproducts
8.4Hoppolyphenols(tannins)
8.5Chemicalidentificationofhopcultivars
8.6References
9Chemistryofwortboiling
9.1Introduction
9.2Carbohydrates
9.3Nitrogenousconstituents
9.3.1Introduction
9.3.2Proteins
9.4Carbohydrate-nitrogenousconstituentinteractions
9.4.1Melanoidins
9.4.2Caramel
9.5Protein-polyphenol(tannin)interactions

9.6Copperfiningsandtrubformation
9.7References
10Wortboiling,clarification,coolingandaeration
10.1Introduction
10.2Theprinciplesofheatingwort
10.3Typesofcoppers
10.4Theadditionofhops
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
10.5Pressurizedhop-boilingsystems
10.5.1Low-pressureboiling
10.5.2Dynamiclow-pressureboiling
10.5.3Continuoushigh-pressureboiling
10.6Thecontrolofvolatilesubstancesinwort
10.7Energyconservationandthehop-boil
10.8Hotwortclarification
10.9Wortcooling
10.10Thecoldbreak
10.11Wortaeration/oxygenation
10.12References
11Yeastbiology
11.1Historicalnote
11.2Taxonomy
11.3Yeastecology
11.4Cellularcomposition
11.5Yeastmorphology
11.6Yeastcytology
11.6.1Cellwall
11.6.2Theperiplasm
11.6.3Theplasmamembrane
11.6.4Thecytoplasm

11.6.5Vacuolesandintracellularmembranesystems
11.6.6Mitochondria
11.6.7Thenucleus
11.7Yeastcellcycle
11.7.1Yeastsexualcycle
11.8Yeastgenetics
11.8.1Methodsofgeneticanalysis
11.8.2Theyeastgenome
11.9Strainimprovement
11.10References
12Metabolismofwortbyyeast
12.1Introduction
12.2Yeastmetabolism±anoverview
12.3Yeastnutrition
12.3.1Waterrelations
12.3.2Sourcesofcarbon
12.3.3Sourcesofnitrogen
12.3.4Sourcesofminerals
12.3.5Growthfactors
12.4Nutrientuptake
12.4.1Sugaruptake
12.4.2Uptakeofnitrogenousnutrients
12.4.3Lipiduptake
12.4.4Ionuptake
12.4.5Transportoftheproductsoffermentation
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12.5Sugarmetabolism
12.5.1Glycolysis
12.5.2Hexosemonophosphate(pentosephosphate)pathway
12.5.3Tricarboxylicacidcycle

12.5.4Electrontransportandoxidativephosphorylation
12.5.5Fermentativesugarcatabolism
12.5.6Gluconeogenesisandtheglyoxylatecycle
12.5.7Storagecarbohydrates
12.5.8Regulationofsugarmetabolism
12.5.9Ethanoltoxicityandtolerance
12.6Theroleofoxygen
12.7Lipidmetabolism
12.7.1Fattyacidmetabolism
12.7.2Phospholipids
12.7.3Sterols
12.8Nitrogenmetabolism
12.9Yeaststressresponses
12.10Minorproductsofmetabolismcontributingtobeerflavour
12.10.1Organicandfattyacids
12.10.2Carbonylcompounds
12.10.3Higheralcohols
12.10.4Esters
12.10.5Sulphur-containingcompounds
12.11References
13Yeastgrowth
13.1Introduction
13.2Measurementofyeastbiomass
13.3Batchculture
13.3.1Brewerybatchfermentations
13.3.2Effectsofprocessvariablesonfermentationperformance
13.4Yeastageing
13.5Yeastpropagation
13.5.1Maintenanceandsupplyofyeastcultures
13.5.2Laboratoryyeastpropagation

13.5.3Brewerypropagation
13.6Fed-batchcultures
13.7Continuousculture
13.8Immobilizedyeastreactors
13.9Growthonsolidmedia
13.10Yeastidentification
13.10.1Microbiologicaltests
13.10.2Biochemicaltests
13.10.3Testsbasedoncellsurfaceproperties
13.10.4Non-traditionalmethods
13.11Measurementofviability
13.12Assessmentofyeastphysiologicalstate
13.13References
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14Fermentationtechnologies
14.1Introduction
14.2Basicprinciplesoffermentationtechnology
14.2.1Fermentabilityofwort
14.2.2Timecourseoffermentation
14.2.3Heatoutputinfermentation
14.3Bottomfermentationsystems
14.3.1Choice,sizeandshapeofvessels
14.3.2Constructionofcylindroconicalvessels
14.3.3Operationofcylindroconicalvessels
14.4Topfermentationsystems
14.4.1Traditionaltopfermentation
14.4.2Yorkshiresquarefermentation
14.4.3BurtonUnionfermentation
14.5Continuousfermentation
14.5.1Earlysystemsofcontinuousfermentation

14.5.2TheNewZealandsystem
14.5.3Continuousprimaryfermentationwithimmobilizedyeast
14.6Fermentationcontrolsystems
14.6.1Specificgravitychanges
14.6.2Othermethods
14.7Summary
14.8References
15Beermaturationandtreatments
15.1Introduction
15.2Maturation:flavourandaromachanges
15.2.1Principlesofsecondaryfermentation
15.2.2Importantflavourchanges 5
15.2.3Techniquesofmaturation
15.2.4Flavour,aromaandcolouradjustmentsbyaddition
15.2.5Maturationvessels
15.3Stabilizationagainstnon-biologicalhaze
15.3.1Mechanismsforhazeformation
15.3.2Removalofprotein
15.3.3Removalofpolyphenols
15.3.4Combinedtreatmentstoremoveproteinandpolyphenols
15.3.5Hazesfromotherthanproteinorpolyphenols
15.4Carbonation
15.4.1Carbondioxidesaturation
15.4.2Carbondioxideaddition
15.4.3Carbondioxiderecovery
15.5Clarificationandfiltration
15.5.1Removalofyeastandbeerrecovery
15.5.2Beerfiltration
15.6Specialbeertreatments
15.6.1Low-alcoholandalcohol-freebeers

15.6.2Icebeers
15.6.3Dietbeers
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15.7Summary
15.8References
16NativeAfricanbeers
16.1Introduction
16.1.1Anoutlineofthestagesofproduction
16.1.2Bouza
16.1.3Merissa
16.1.4Busaaandsomeotherbeers
16.1.5SouthernAfricanbeers
16.2Maltingsorghumandmillets
16.3BrewingAfricanbeersonanindustrialscale
16.4AttemptstoobtainstableAfricanbeers
16.5Beercompositionanditsnutritionalvalue
16.6References
17Microbiology
17.1Introduction
17.2Themicrobiologicalthreattothebrewingprocess
17.3Beerspoilagemicro-organisms
17.3.1Detectionofbrewerymicrobialcontaminants
17.3.2Identificationofbrewerybacteria
17.3.3Gramnegativebeerspoilingbacteria
17.3.4Grampositivebeerspoilingbacteria
17.3.5Beerspoilageyeasts
17.3.6Microbiologicalmediaandthecultivationof
micro-organisms
17.4Microbiologicalqualityassurance
17.5Sampling

17.5.1Samplingdevices
17.6Disinfectionofpitchingyeast
17.7Cleaninginthebrewery
17.7.1Rangeofcleaningoperations
17.7.2CIPsystems
17.7.3Cleaningagents
17.7.4Cleaningbeerdispenselines
17.7.5ValidationofCIP
17.8References
18Brewhouses:types,controlandeconomy
18.1Introduction
18.2Historyofbrewhousedevelopment
18.2.1Thetowerbrewerylay-out
18.2.2Thehorizontalbrewerylay-out
18.3Typesofmodernbrewhouses
18.3.1Experimentalbrewhouses
18.3.2Micro-andpubbreweries
18.4Controlofbrewhouseoperations
18.4.1Automationinthebrewhouse
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
18.4.2Schedulingofbrewhouseoperations
18.5Economicaspectsofbrewhouses
18.6Summary
18.7References
19Chemicalandphysicalpropertiesofbeer
19.1Chemicalcompositionofbeer
19.1.1Inorganicconstituents
19.1.2Alcoholandoriginalextract
19.1.3Carbohydrates
19.1.4Otherconstituentscontainingcarbon,hydrogenand

oxygen
19.1.5Nitrogenousconstituents
19.1.6Sulphur-containingconstituents
19.2Nutritivevalueofbeer
19.3Colourofbeer
19.4Haze
19.4.1Measurementofhaze
19.4.2Compositionandformationofhaze
19.4.3Predictionofhazeandbeerstability
19.4.4Practicalmethodsforimprovingbeerstability
19.5Viscosity
19.6Foamcharacteristicsandheadretention
19.6.1Methodsofassessingfoamcharacteristics
19.6.2Beercomponentsinfluencingheadretention
19.6.3Headretentionandthebrewingprocess
19.7Gushing
19.8References
20Beerflavourandsensoryassessment
20.1Introduction
20.2Flavour±tasteandodour
20.3Flavourstability
20.4Sensoryanalysis
20.5References
21Packaging
21.1Introduction
21.2Generaloverviewofpackagingoperations
21.3Bottling
21.3.1Managingthebottleflow
21.3.2Managingthebeerflow
21.3.3Managingplantcleaning

21.3.4Materialsformakingbottles
21.4Canning
21.4.1Thebeercan
21.4.2Preparingcansatthebreweryforfilling
21.4.3Canfilling
21.4.4Canclosing(seaming)
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
21.4.5Widgetsincans
21.5Kegging
21.5.1Thekeg
21.5.2Treatmentofbeerforkegging
21.5.3Handlingofkegs
21.5.4Keginternalcleaningandfilling
21.5.5Kegcappingandlabelling
21.5.6Smoothflowaleinkegs
21.6Caskbeer
21.6.1Thecask
21.6.2Handlingcasks
21.6.3Preparingbeerforcaskfilling
21.6.4Caskfilling
21.7Summary
21.8References
22Storageanddistribution
22.1Introduction
22.2Warehousing
22.2.1Principlesofwarehouseoperation
22.2.2Safetyinthewarehouse
22.3Distribution
22.3.1Logistics
22.3.2Qualityassurance

22.4Summary
22.5References
23Beerinthetrade
23.1Introduction
23.2History
23.3Beercellars
23.3.1Hygiene
23.3.2Temperature
23.3.3Lighting
23.4Beerdispense
23.4.1Kegbeer
23.4.2Caskbeer
23.4.3Bottledandcannedbeer
23.5Qualitycontrol
23.6Newdevelopmentsintradequality
23.7Summary
23.8References
Appendix:unitsandsomedataofuseinbrewing
TableA1SIderivedunits
TableA2PrefixesforSIunits
TableA3Comparisonofthermometerscales
TableA4Interconversionfactorsforunitsofmeasurement
TableA5Specificgravityandextracttable
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
TableA6EquivalencebetweenInstituteofBrewingunitsofhot
waterextract
TableA7Solutiondivisorsofsomesugars
TableA8Somepropertiesofwateratvarioustemperatures
TableA9Thedensityandviscosityofwateratvarioustemperatures
TableA10Somemorepropertiesofwater

TableA11Therelationshipbetweentheabsolutepressureandthe
temperatureofwater-saturatedsteam
TableA12Thesolubilityofpuregasesinwateratdifferent
temperatures
TableA13Saltsinbrewingliquors
TableA14Unitsofdegreesofwaterhardness
TableA15Characteristicsofsomebrewingmaterials
TableA16Pasteurizationunits
Fig.A1Therelationshipsbetweenethanol/watermixturesandthe
densitiesofthesolutions.
References
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
ThetwovolumesofthesecondeditionofMaltingandBrewingScienceI,MaltandSweet
WortandII,HoppedWortandBeer,byJamesS.Hough,DennisE.Briggs,Roger
StevensandTomW.Young,appearedin1981and1982.Thisbookprovidedthe
frameworkfortheM.Sc.inMaltingandBrewingScience,thecoursethatwasofferedby
theBritishSchoolofMaltingandBrewingintheUniversityofBirmingham(UK).Italso
providedthebackboneofmanyothercourses.Aftermorethan20yearsthedemandfor
thesevolumeshascontinued,althoughtheyareincreasinglyoutofdate.Maltsand
Malting,byDennisE.Briggs,appearedin1998,andBrewingYeastandFermentation,
byChrisBoultonandDavidQuain,becameavailablein2001.Thesebookscovertheir
namedtopicsindepth.However,theneedforanup-to-date,integratedtextbookon
brewing,comparableinscopeanddepthofcoveragetoMaltingandBrewingScience,
remained.
Brewing:Scienceandpracticeisintendedtomeetthisneed.Decidingonthedetailsof
thecoveragehasgivenrisetosomeanxiousdiscussions.Practicallyitisimpossibleto
describeallaspectsofallthevarietiesofbrewingprocessesindepth,inonemoderately
sizedvolume.Inevitablyithasbeennecessarytoassumesomebackgroundknowledgeof
physics,chemistry,biology,andengineering.However,thebookisunderstandableto
peoplewithoutdetailedknowledgeintheseareas.Thereferencesattheendofeach

chapterprovideguidanceforfurtherreading.Sincethewiderangeofkindsofbrewing
operations,fromsimple,low-volume,single-linebreweriestoextremelylarge,highly
complex,multiple-lineinstallations,doesnotallowasingledescriptionofbrewing
activities,thebookconcentratesontheprinciplesofthevariousbrewingprocesses.
Brewingiscarriedoutallovertheworldand,unsurprisingly,differentterminologies
andmethodsofmeasurementandanalysisareused.Thedifferentsystemsofunitsand
analysesareexplainedinthetextandconversionfactors(wherevalid)andsomeother
usefuldataaregivenintheAppendix.Alistofabbreviationsisincludedintheindexfor
reference. The index also includes a list of formulae
First of all the authors warmly thank our wives, Rosemary, Wendy, Stella and Betty,
for their unfailing patience and good-humoured support. We have also been given a great
deal of help from our colleagues and friends. We are grateful to Mrs Doreen Hough for
Preface
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
permission to use some of the late Professor Jim Hough's diagrams. Permission to use
other diagrams is acknowledged in the text. We would like to thank: Mrs Marjorie
Anderson, Dr John M. H. Andrews, Mrs Marjorie Anderson, Dr Raymond G. Anderson,
Mr David J. Banfield, Mr Zane C. Barnes, Herr Volker Borngraber, Mr Andy Carter, Dr
Peter Darby, Mr J. Brian Eaton, Dr David L. Griggs, Dr Paul K. Hegarty, Mrs Sue M.
Henderson, Mr James Johnstone, Mr Roy F. Lindsay, Dr G. C. Linsley-Noakes, Dr David
E. Long, Mr John MacDonald, Dr Ray Marriott, Mr P. A. (Tom) Martin, Dr A. Peter
Maule, Ms Elaine McCri mmon, Dr Philip Morrall, Dr Ray Neve, Dr George Philliskirk,
Dr David E. Quain, Mr Trevor R. Roberts, Mr Derek Wareham and Dr Richard D. J.
Webster. We also wish to thank Coors Brewers for the use of the Technical Centre,
Burton-on-Trent.
We apologise if any acknowledgements have been omitted.
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
1.1Introduction
Beersandbeer-likebeveragesmaybepreparedfromrawcerealgrains,maltedcerealgrains
and(historically)bread.Thisbookisprimarilyconcernedwithbeersofthetypesthat

originatedinEurope,butwhicharenowproducedworld-wide.However,anaccountis
givenof`African-style'beers(Chapter16).ThemostsimplepreparationofEuropean-style
beersinvolves(a)incubatingandextractingmalted,groundupcerealgrains(usually
barley)withwarmwater.Sometimesthegroundmaltismixedwithotherstarchymaterials
and/orenzymes.(b)Thesolutionobtainedisboiledwithhopsorhoppreparations.(c)The
boiledsolutionisclarifiedandcooled.(d)Thecooledliquidisfermentedbyaddedyeast.
Usuallythebeerisclarified,packagedandservedwhileeffervescentwithescapingcarbon
dioxide.Inthischapterthepreparationofbeersisoutlinedandthebrewers'vocabularyis
introduced.Beersaremadeinamountsrangingfromafewhectolitres(hl)aweekto
thousandsofhl.Theyaremadeusingvariousdifferentsystemsofbrewing.
1.2Malts
Maltsaremadefromselectedcerealgrain,usuallybarley,(butsometimeswheat,rye,
oats,sorghumormillet),thathasbeencleanedandstoreduntildormancyhasdeclined
anditisneeded.Itisthengerminatedundercontrolledconditions.Theirpreparationis
outlinedinChapter2,andisdescribedindetailinBriggs(1998).Thegrainishydrated,
or `steeped', by immersion in water. During steeping the water will be changed at least
once, air may be sucked through the grain during `dry' periods betwee n immersions, and
may be blown into the grain while immersed. After steeping the grain is drained and is
germinated to a limited extent in a cool, moist atmosphere with occasional turning and
mixing to prevent the rootlets matting together. During germination the acrospire
(coleoptile) grows beneath the husk and rootlets grow from the end of the grain, enzymes
accumulate and so do sugars and other soluble materials. The dead storage tissue of the
grain, the starchy endosperm, is partly degraded, or `modified', and its physical strength
1
An outline of brewing
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
isreduced.Whengerminationand`modification'aresufficientlyadvancedtheyare
stoppedbykilning.The`greenmalt'(greeninthesenseofimmature,itisnotgreenin
colour)iskilned,thatis,itisdriedandlightlycooked,orcured,inacurrentofwarmto
hotair.Pale,`white'maltsarekilnedusinglowtemperaturesandintheseenzyme

survivalisconsiderable.Indarker,colouredmalts,kilnedusinghighertemperatures,
enzymesurvivalisless.Inextremecasesthedarkest,specialmaltsareheatedina
roastingdrumandcontainnoactiveenzymes.Afterkilningthemaltiscooledand
`dressed',thatis,thebrittlerootlets(`culms',sprouts)arebrokenoffandtheyanddust
areremoved.Theculmsareusuallyusedforcattlefood.Palemaltsareusuallystoredfor
someweeksbeforeuse.Incontrasttothetough,ungerminatedbarleygrainmaltis
`friable',thatis,itiseasilycrushed.
1.3Mashtunadjuncts
Mashtunadjunctsarepreparationsofcereals(e.g.,flakedmaizeorriceflakes,wheat
flour,micronizedwheatgrains,orriceormaizegritswhichhavetobecookedseparately
inthebrewery)whichmaybemixedwithgroundmaltinthemashingprocess.Theuseof
anadjunctaltersthecharacterofthebeerproduced.Anadjunct'sstarchishydrolysed
duringmashingbyenzymesfromthemalt,soprovidinga(sometimes)lessexpensive
sourceofsugarsaswellaschangingthecharacterofthewort.Sometimesmicrobial
enzymesareaddedtothemash.Inafewcountriestheuseofadjunctsisforbidden.In
GermanytheReinheitsgebotstipulatesthatbeermaybemadeonlywithwater,malt,hops
andyeast.
1.4Brewingliquor
Inbrewing,wateriscommonlyknownasliquor.Itisusedformanypurposesbesides
mashing,includingbeerdilutionattheendofhigh-gravitybrewing,cleaningandin
raisingsteam.Waterforeachpurposemustmeetdifferentqualitycriteria(Chapter3).
Thebrewingliquorusedinmashingmustbeessentially`pure',butitmustcontain
dissolvedsaltsappropriateforthebeerbeingmade.Thequalityoftheliquorinfluences
thecharacterofthebeermadefromit.Famousbrewinglocationsgainedtheir
reputations,atleastinpart,fromthequalitiesoftheliquorsavailabletothem.Thus
Burton-on-Trentisfamousforitspaleales,DublinforitsstoutsandPilsenforitsfine,
palelagers.Itisnowusual,atleastinlargerbreweries,toadjustthecompositionofthe
brewingliquor(Chapter3).
1.5Millingandmashingin
Themalt,sometimespremixedwithparticularadjuncts,isbrokenuptoacontrolled

extentbymillingtocreatethe`grist'.Thetypeofmillusedandtheextenttowhichthe
malt(andadjunct)isbrokendownischosentosuitthetypesofmashingandwort-
separationsystemsbeingused(Chapter5).Ifdrymillingisusedthegrist,possiblymixed
with adjuncts, is collected in a container, the grist case.
At mashin g-in (doughing-in) the grist is intimately mixed with brewing liquor, both
flowing at controlled rates, into a mashing vessel at an exactly controlled temperature.
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
Theresulting`mash',withtheconsistencyofathinslurry,isheldforaperiodof
`conversion'.Theobjectiveistoobtainamashthatwillyieldasuitable`sweetwort',a
liquidrichinmaterialsdissolvedfromthemaltandanyadjunctsthathavebeenused.The
dissolvedmaterial,the`extract',containssolublesubstancesthatwerepreformedinthe
gristandothersubstances(especiallycarbohydratesderivedfromstarch),thatareformed
frompreviouslyinsolublematerialsbyenzyme-catalysedhydrolyticbreakdownduring
mashing.
1.6Mashingandwortseparationsystems
Themajormashingsystemsare,broadly,(a)thesimplest,nearlyisothermal,infusion
mashingsystem,(traditionalforBritishalebrewers);(b)thedecoctionsystem,
(traditionalformainlandEuropeanlagerbrewers);(c)thedoublemashsystem,(common
inNorthAmericanpractice);(d)thetemperature-programmedinfusionmashingsystem
thatisbeingwidelyadoptedintheUKandmainlandEurope(Chapters4and5).Amash
should be held at a chosen temperat ure (or at successive different temperatures), for pre-
determined times, to allow enzymes to `convert' (degrade) the starch and dextrins to
soluble sugars, to cause the partial breakdown of proteins, to degrade nucleic acids and
other substances. At the end of mashing the sweet, or unhopped wort (the solution of
extractives, mainly carbohydrates; the `extract') is separated from the undissolved solids,
the spent grains or draff.
Infusion mashing is carried out in mash tuns. Mash conversion and the separation of
the sweet wort from the spent grains take place in this vessel. The coarsely ground grist,
made with a high proportion of well-modified malt, is mashed in to give a relatively
thick, porridge-like mash at 63À67 ëC (145.4À152.6 ëF). After a stand of between 30

minutes and two and a half hours the wort (liquid) is withdrawn from the mash. The first
worts are cloudy and are re-circulated, but as the run off is continued the wort becomes
`bright' (clear), because it is filtered through the bed of grist particles. When bright the
wort is either collected in a holding vessel (an underback) or it is moved directly to a
copper to be boiled with hops. Most of the residual extract, initially entrained in the wet
grains, is washed out by sparging (spraying) hot liquor, at 75À80 ëC (167À176 ëF ) over
the goods.
Decoction mashing is carried out with more finely ground grists, originally made with
malts that were undermodified. These mashes are relatively `thin', so they may be moved
by pumping and can be stirred. Decoction mashing uses three vessels, a stirred mash
mixing vessel, a stirred decoction vessel or mash cooker and a wort separation device,
either a lauter tun or a mash filter. In one traditional mashing programme the grist is
mashed in to give an initial temperature of around 35 ëC (96 ëF). After a stand a decoction
is carried out, that is, a proportion of the mash, e.g., a third, is pumped to the mash
cooker, where it is heated to boiling. The boiling mash is pumped back to the mash
mixing vessel and is mixed with the vessels contents, raising the temperature to, e.g.,
50 ëC (122 ëF). After another stand a second decoction is carried out, increasing the
temperature of the mixed mash to about 65 ëC (149 ëF). A final decoction increases the
mash temperature to about 76 ëC (167 ëF). The mash is then transferred to a lauter tun or a
mash filter. The sweet wort and spargings are collected, ready to be boiled with hops.
Typically, double-mashing uses nitrogen- (`protein-') and enzyme-rich malts and
substantial quantities of maize or rice grits. It also involves the use of three vessels. Most
of the malt grist is mashed into a mash-mixing vessel to give a mash at around 38 ëC
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
(100.4ëF).Thegrits,mixedwithasmallproportionofgroundmaltand/orapreparation
ofmicrobialenzymes,aremashedinaseparatevesselcalledacerealcooker.The
contentsarecarefullyheatedwithmixing,andarestatabout70ëC(158ëF),to100ëC
(212ëF)todispersethestarchandpartlyliquefyit.Theadjunctmashispumpedfromthe
cerealcookerintothemaltmash,withcontinuousmixing,togiveafinaltemperatureof
about70ëC(158ëF).Afterastandthemashisheatedtoabout73ëC(163.4ëF),thenitis

usuallytransferredtoalautertunforwortcollection.
Temperature-programmedinfusionmashingisincreasinglydisplacingoldermashing
systems.Thegristisfinelygroundandthemashismade`thin'toallowittobestirred.
Thegristismashedintoastirredandexternallyheatedmash-mixingvesseltogivean
initialtemperatureof35ëC(95ëF)forapoorlymodifiedmaltor50ëC(122ëF),ormore,
forabettermodifiedmalt.Themashisheated,with`stands'typicallyat50ëC(122ëF),
65ëC(149ëF)and75ëC(167ëC).Thenthesweetwortiscollectedusingalautertunora
mashfilter.
1.7Thehop-boilandcopperadjuncts
Thesweetwortistransferredtoavessel,acopperorkettle,inwhichitisboiledwithhops
orhoppreparations,usuallyfor1±2hours.Hopsarethefemaleconesofhopplants.They
maybeusedwhole,orgroundup,oraspelletsorasextracts.Thechoicedictatesthetype
ofequipmentusedinthenextstageofbrewing.Pelletedpowdersareoftenpreferred.Hops
contributevariousgroupsofsubstancestothewort.Duringboilinganumberofchanges
occurinthewortofwhichthemoreobviousarethecoagulationofproteinas`hotbreak'or
`trub',thegainingofbitternessandhoparomaandthedestructionofmicro-organisms
(Chapters9and10).Evaporationofthewort,reducesthevolumeby,say,7±10%,andsoit
is concentrated. Unwanted flavour-rich and aromatic volatile substances are removed.
When used, sugars, syrups and even malt extracts (copper adjuncts) are dispersed and
dissolve in the wort during the copper boil. During the boil flavour changes and a
darkening of the colour occurs. Caramels may be added at this stage to adjust the colour.
The hop-boil consumes about half of the energy use in brewing.
1.8 Wort clarification, cooling and aeration
At the end of the boil the transparent, or `bright' wort contains flocs of trub (the hot
break) and suspended fragments of hops. If whole hops were used then residual solids are
strained off in a hop back or other filtration device and the bed of hop cones filters off the
trub, giving a clear, hopped wort. However, if powders, hop pellets, (which break up into
small particles), or extracts were used then hop fragments (if present) and the trub are
usually separated in a `w hirlpool tank'. The clear `hopped wort' is cooled to check
continuing darkening and flavour changes and so it can be inoculated (`pitched') with

yeast, and can be aerated or oxygenated without a risk of oxidative deteriora tion. The
heated cooling water is used for various purposes around the brewery. During cooling a
second separation of solids occurs in the wort. This `cold break' is composed mostly of
proteins and polyphenols and some associated lipids. It is often, but not always,
considered desirable to remove this material to give a `bright', completely clear wort. The
wort is aerated or even oxygenated, to provide oxygen for the yeast in the initial stages of
fermentation.
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
1.9Fermentation
Fermentationmaybecarriedoutinmanydifferenttypesofvessel(Chapter14;Boulton
andQuain,2001).Fermentersmaybeopenorcompletelyclosedortheymayallowpart
oftheyeasttobeexposedtotheairforpartofthefermentationperiod.Thevarietyof
fermentersremainsbecauseyeastsworkingindifferentvesselsproducebeerswith
differentflavours.Wortfermentationisinitiatedbypitching(inoculating)thecooled,
hoppedwortwithaselectedyeast.Inafewcasesmixturesofyeastsareused.Brewery
yeastisamassoftiny,single,ovoidcells(Saccharomycescerevisiae,the`sugarfungus
ofbeer').Yeaststrainsvaryintheirpropertiesandtheflavourstheyimpart.Inaveryfew
cases,aswithBelgianGueuzeandLambicbeers,(orsomeAfricanbeers;Chapter16),
fermentation occurs `spontaneously' and a comple x mixture of microbes is involved. The
yeast metabolizes extract substances dissolved in the wort. More yeast cells and `minor'
amounts of many substances are produced, some of which add to the beer's character.
The major products of carbohydrate metabolism are ethyl alcohol (ethanol), carbon
dioxide and heat. The yeast multiplies around 3±5 times. Some is retained for use in
subsequent fermentations, while the surplus is disposed of to distillers or the makers of
yeast extracts.
Traditionally, ales are fermented with `top yeasts' which rise to the top of the beer in
the head of foam. These are pitched at about 16 ëC (61 ëF) and fermentation is carried out
at 15À20 ëC (59À68 ëF) for 2±3 days. Traditional lagers are fermented with `bottom
yeasts', which settle to the base of the ferme nter. These are pitched at lower temperatures
(e.g., 7À10 ëC; 44.6À50 ëF) and fermentations are also carried out at lower temperatures

(e.g., 10À15 ëC; 50À59 ëF), consequently they take longer than ale fermentations. As
wort is converte d into beer the removal of materials (especially sugars) from solution and
the appearance of ethanol both contribute to the decline in specific gravity. The initial or
original gravity, OG, the final or present gravity at the end of the fermentation, FG or PG,
and the final alcohol content, are important characteristics of beers.
Yeasts are selected with reference to:
1. their rate and extent of growth
2. the rate and extent of fermentation
3. the flavour and aroma of the beer produced
4. in older fermentation system s it is imperative that top yeasts rise into a good head of
foam and bottom yeasts sediment cleanly.
Subs tance s (fin ings) may be added to promote yeast separatio n at the end of
fermentation. However, in some modern systems `powdery' yeasts are employed that
stay in suspension until the beer is chilled or until collected by centrifugation.
1.10 The processing of beer
When the main, or `primary' fermentation is nearly complete the yeast density is reduced
to a pre-determined value. The `green' or immature beer (it is not green in colour, but has
an unacceptable, `immature' flavour) is held for a period of maturation or secondary
fermentation. During this process the flavour of the mature beer is refined. Sometimes
`priming' sugar or a small amount of wort is added to boost yeast metabolism and the
`maturation', `conditioning' or `lagering' process. (Lagern is Germ an and means stored
or deposited). In traditional lager brewing the immature beer was stored cold, e.g., at
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
À2 ëC (28.4 ëF), for extended perio ds, sometimes months, when a very slow secondary
fermentation occurred and yeast and cold trub settled to the base of the storage vessel.
Conditioning is carried out in various ways. The primary and secondary fermentations
were carried out in separate, special vessels but increasingly single vessels are used.
Traditionally, ales are run from fermenters into casks or bottles with a little sugar, finings
and a regulated amount of yeast. The secondary fermentation `conditions' the beer in the
container, charging it with carbon dioxide. The ale is dispensed from above a layer of

settled yeast. Such naturally conditioned beers are now made in only small amounts.
These beers are not stable for extended periods and they require careful, intelligent
handling.
Now, after conditioning in bulk, most beers are chilled and filtered or centrifuged to
remove residual yeast. These completely bright beers are then carbonated, that is, their
carbon dioxide content is adjusted, they are transferred into bottles, cans, kegs, or bulk
tanks. Nitrogen gas is sometimes added to the package, so the beer contains both this and
carbon dioxide, but as far as possible air is excluded. Before packaging the beer may be
sterile filtered, a process that avoids flavour damage but it follows that all subsequent
beer movements must be made under rigidly aseptic conditions. More often the beer is
pasteurized, that is, it is subjected to a carefully regulated heat treatment. This may be
applied to the filled bottles or cans or to the flowing beer as it moves to fill a sterile
container. With the notable exceptions of some dark stouts and wheat beers, such beer s
should (a) be brilliantly clear, (b) develop a stable white foam, or head, when poured into
a clean glass, and (c) their flavours and gas-contents should remain steady.
The careful selection of raw materials and processing conditio ns help brewers to
approach these objectives. However, it may be necessary to employ other techniques. For
example, the plant proteolytic enzyme papain may be added to beer, or the beers may be
treated with insoluble adsorbents to remove haze precursors. In addition substances may
be added to reduce the dissolved oxygen content of the beer, to maximize its haze and
flavour stability. Other substances may be added to stabilize beer foam.
1.11 Types of beer
There is no truly satisfactory classification of beers. `Clear, European-style beers' may be
distinguished by the raw materials used in their preparation, the ways in which the
brewing operations are carried out, whether top, bottom or `bulk' fermentation is used,
how the product is conditioned, whether it is chilled and filtered and carbonated or is
conditioned in bottle or cask and how it is packaged. Stouts, porters and wheat beers,
which are produced in conventional ways, are often not transparent. A beer may also be
distinguished by its OG and degree of attenua tion or alcohol content, colour, acidity,
flavour and aroma, by its `body' or `mouth feel', by its head (foam) characteristics and by

its physiological effects. How a drinker perceives a beer is influenced by many factors,
including the manner in which it is served, its temperature, clarity and colo ur, flavour,
aroma and `character', the ambience, and whether or not it is being taken with food and
what has been consumed before.
Within each grouping, `class' or `style', individual beers may be quite distinct and
brewers aim to produce distinctive products. In North America most beer is pale, lightly
hopped and served very cold (often at about 0 ëC; 32 ëF). Many new, small breweries have
been set up and these make a wide variety of beers based on styles from around the world.
In Europe, for about a century, British brewing practices diverged from those of mainland
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
producers,butinrecentyearsconvergencehasstarted.Forexample,inGermanymost
beers(notall)weremadeusingdecoctionmashing,bottomfermentationandlongperiods
ofcoldstorage(lagering).Increasingly,temperatureprogramming,infusionmashing,
bulkfermentationandshorterperiodsoflageringarebeingused.Undermany
circumstancestheuseofadjunctsisstillnotused.AlthoughunderEEClegislationthe
useofadjunctsisallowed,mostGermanbrewersstillabidebytheReinheitsgebotfor
domesticbeers.
ThemaingroupsofbeersaretheverypalePilsentypes,palegolden-brownViennatypes,
andthedarker,richMunichtypes.OtherbeersincludeMaÈrzen,Oktoberfest,wheatbeers,
ryebeersandsmokedbeers.IntheUKlagerwortsareproducedinmanyways,buttheyare
bottomfermented.TheBritish`lagers'areallpalebeers.Alesaretraditionallymadewithan
infusionmashingsystem.Theyaremoderatelystronglyhoppedandatopfermentation
systemisused.Traditionalgroupsarethe(progressivelydarker)paleales,mildales(usually
darker,sweeterandlessstronglyhopped),brownales(darkerformsof`mild'),andstoutsor
`porters'.Thedistinctionsbetweenaleandlagerbreweriesareincreasinglyblurredassome
brewersadoptsimilarwortproductionandfermentationsystems.
Lesscommonproductsincludewheatbeers,low-alcoholandalcohol-freebeers
(whichmaybecarbonatedworts,underfermentedbeersorbeersfromwhichthealcohol
hasbeenremoved),andbeerswithexceptionallyhighalcoholcontents(e.g.,barleywines
andTrappistbeers,with9%ABV,ormore).Inlowcarbohydrate(lite,lightordietetic)

beers,preparedbyusingspecialmashingconditionsandaddedstarch-degrading
enzymes,essentiallyallthestarch-deriveddextrinsaredegradedtofermentablesugars
andareutilizedbytheyeast.Africanopaquebeers(Chapter16)andkvass(Russian)are
distinctproducts.Someunusualbeers,madeinBelgium,includeLambic,Gueuzeand
fruit-flavouredbeers(kriek,flavouredwithcherries;framboise,flavouredwith
raspberries).Theseareallmadeusingspontaneousfermentationswhichinvolvemixtures
oforganisms.
Beerstrengthmaybedefinedinseveralways;bythespecificgravityofthewortbefore
fermentation(theOG),bythealcoholcontentofthefinalbeer(%alcoholbyvolumeor
ABV)orevenbythecontentofhopbittersubstances.Thefermentabilityofextract
dependsonmanyfactors.ThereisnofixedrelationshipbetweentheOGandthealcohol
contentofabeer.InBritainthespecificgravityofawortorbeerisusuallyquotedtimes
1,000so,forexample,waterhasaSGof1000.00andwortwithaspecificgravity(s.g.)of
1.040at20ëC(68ëF)hasaSGof1040.00.Inthepast,extractwascalculatedasbrewer's
poundsperbarrel,andtheexcessweight(inlb.)overwaterwasreferredtoasbrewer's
poundsgravity.Thusabarrelofwater(36imp.gallons,UK)weighs360pounds(lb.),buta
barrelofwortatSG1040weighed374.2lb.Sothisworthadagravityof14.2lb.Outside
theUKconcentrationsareoftenexpressedintermsofconcentrationsofsucrosesolutions
ofthesamegravity(seeappendix).Thus,invonBalling'stablesof1843wortofaspecific
gravity of 1040 is equivalent to a sucrose solution of 9.95% (w/w). Von Balling's tables
were revised by Plato in 1918 and gravity is often expressed as degrees Plato. Increasingly
beer strengths are being given as the concentration of alcohol % ABV that they contain.
1.12 Analytical systems
For both trading and quality-control purposes all the materials used in making beers, the
liquor, the sweet and hopped worts and the beers themselves are analysed. Not all the
methods used are standardized and, regrettably, there are at least four `agreed', but
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
discordant,setsofmethodsinuse.Themethodsusedinthedifferentsetsdiffer
significantlyandgivedifferentresults.Inmanyinstancestherearenovalidorreliable
conversionfactorstointerconvertanalyticalresults.Themostcommonlyusedmethods

arethoseoftheInstituteofBrewing(IoB;nowtheInstituteandGuildofBrewing,IGB),
theEuropeanBreweryConvention(EBC),theAmericanSocietyofBrewingChemists
(ASBC)andthemethodsoftheMitteleuropaÈischenAnalysenKommission(MEBAK).
Themethodsarefrequentlyrevised,successiveversionsbeingdistinguishedbytheir
dates.Inthisbookthemostrecentunitsareusedwhereverpossible.By2005themethods
oftheIGBandtheEBCshouldhavebeenmerged.Thenumberofunitsofmeasurement
inuseislarge.Heremetricunitshavebeenusedwherepossible,withBritish(UK)
equivalentsso,forexample,hectolitresandimperialgallons.Itshouldbenotedthatthe
Americangallon(US)hasonlyabout0.8ofthevolumeofanimperialgallon.Systemsof
unitsandconversionfactorsaregivenintheAppendix.
1.13 The economics of brewing
The economics of brewing are influenced by many factors, including the manning levels
required, the local costs of labour, raw materials, how brewing practices are influenced
by governmental regulations and how the products are taxed. The scales of brewery
operations vary widely, from units that produce ` 10 barrels (imp. brl, approx.16.4
hectolitres, hl) per week to b 30,000 imp. brl (49,092 hl) per week. Thus savings per imp.
brl that are trivial to the small-scale brewer are worthwhile to a larger operator. Breweries
that operate continuously, for 24 hours a day, use their capital investment in plant to the
best effect and they can also make other savings, for example, by using heat-recovery
systems that are not suitable for breweries that operate intermittently. There are strong
and increasing pressures to minimize water use, to minimize the production of wastes and
effluents and the release of heat and odorous gases (such as vapours from hop-boiling),
and `greenhouse gases' such as carbon dioxide and refrigerants, to utilize raw materials as
efficiently as possible, and to utilize fuels and power efficientl y.
In order to use plant at peak efficiency it is necessary to have it well engineered,
instrumented, automated and maintained so that it can opera te nearly continuously. To
make such investment worthwhile the capacity of the plant must be large and, in
consequence, the manpower needed to produce a given volume of beer is lower than is
needed with less sophisticated plant. The personnel needed to operate modern plant
successfully must be highly trained. Such plant is most efficient at making large volumes

of relatively few beers. Smaller, more labour-intensive plants are often better suited for
making a wide variety of beers in smaller amounts. Large brewing companies tend to
produce fewer beers in larger and larger plants. The problems of `product matching', of
trying to make large volumes of one beer in different breweries, are notorious. Smaller
breweries, making smaller volumes, often of more `spe cialist', and even `eccentric'
beers, are appearing all the time. Smaller breweries usually deliver beer over a small area,
and so have lower transportation costs relative to larger breweries, which must deliver to
larger areas to market the larger amounts of beer that they produce.
Energy and water requirements per unit volume of beer produced vary widely. In part
this is due to differences in the efficiencies of production plants, but it also depends on
the production processes used and on how the beer is packaged. Thus decoction mashing
uses more energy than temperature-programmed infusion mashing. Not all breweries
recover heat from the vapours in their mash-c ooker or copper-stacks, and the efficiency
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC
of heat recovery varies with the sophistication of the equipment used. The heat, power
and water usage in bottling and canning halls (which not all breweries have) is high,
because of the amount of washing carried out, the conveying and the heat used by the
pasteurizers.
A widely adopted technique for improving the economics of a brewery is `high gravity'
(HG) brewing, in which concentrated worts are produced and processed. The concentrated
beers produced are diluted for sale. Thus a larger volume of beer is produced, per brew,
than would have been the case had the plant been operated in the conventional way. HG
brewing is a technically sophisticated process. There are difficulties with preparing
concentrated worts unless the addition of sugars or syrups to the copper is allowed. Almost
all the stages of the brewing process have to be adjusted, and the water used to dilute the
HG beer must be very carefully sterilized, deoxygenated and carbonated.
1.14 Excise
Beer is usually taxed. In Britain malt was taxed and the regulations imposed, to maximize
the tax receipts, fossilized the malting and brewing processes. The malt tax was
withdrawn in 1880, but the styles of beers that had been produced using well modified ale

malts were established as `traditional' and continued in use. Only recently have newer
methods of brewing been widely adopted. Next, tax was levied on the gravity and volume
of the brewer's wort, after boiling and cooling. The consequent economic need to convert
as high a proportion of this wort as possible into saleable beer influenced the designs of
fermentation vessels and yeast propagators, the recovery of beer from harvested yeast,
from filters, and so on. At present in the UK, and many other countries, excise is levied
on the volume and alcohol content (ABV) of the beer leaving the brewery. Sometimes
beers are classified according to the alcohol band (range of strengths) in which it falls.
Each band is taxed at a different rate and the tax increases with the alcohol content. There
are countries where the beer is taxed by volume only.
1.15 References and further reading
1.15.1 The systems of malting and brewing analysis
ASBC (1992) The American Society of Brewing Chemists. Methods of analysis (8th edn, revised), ASBC,
St. Paul, Minn.
EBC (1997; 1998) European Brewery Convention. Analytica-EBC (5th edn, with revisions), Fachverlag
Hans Carl, Nu
È
rnberg.
IoB (1997) The Institute of Brewing, Recommended Methods of Analysis (2 volumes, and revisions), The
Institute and Guild of Brewing, London.
MEBAK (1993) Bra utec hnische Analysenmethoden: Methodensammlung der Mitte leuropa
È
ischen
Brautechnischer Analysenkommission (5 volumes).
1.15.2 General
BAMFORTH, C. W. (1998) Beer; tap into the art and science of brewing, London, Insight Press, 245 pp.
BAMFORTH, C. W. (2002) Standards of Brewing: a practical approach to consistency and excellence,
Boulder, Colorado, Brewers' Publications, 209 pp.
BOULTON, C. and QUAIN, D. (2001) Brewing Yeast and Fermentation, London, Blackwell Science, 644 pp.
BRIGGS, D. E. (1998) Malts and Malting, London, Blackie Academic and Professional/Gaithersburg,

Aspen Publishing, 796 pp.
COULTATE, T. P. (2002) Food, the chemistry of its components, (4th edn), Cambridge, The Royal Society
of Chemistry, 432 pp.
Copyright © 2004 Woodhead Publishing Limited and CRC Press, LLC