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Brewing with Brettanomycesthe horse the goat and the barnyard
ChadYakobsonOwner/Brewer
6/16/2011
• Msc.BrewingandDistilling‐ICBD,Heriot‐WattUniversityEdinburgh,Scotland• Dissertationtitled:PureCultureFermentationCharacteristicsofBrettanomycesYeastSpeciesandTheirUseintheBrewingIndustry
• BrewedforOdellBrewingCompany• Sabotuer• Friek• Deconstruction
• OpenedCrookedStaveNovember1st2010• BrewedourFirstBatchJune10th,2011
• 100%Brettanomycesprimaryfermentationinoakbarrels…stillaging!
• WildWildBrett‐Seriesof100%Brettprimaryfermentedbeers• Barrel‐agedSourBeers‐L’Brettd’Or,NightmareonBrettstreet,Reverentia• PetiteSour‐PartialBrettprimaryinspontaneouslysouredwortblendedinlargeoakfoeder
• Surette‐Saisonwildale,mixedhouseculturefermentedentirelyinoakfoeder
Crooked Stave Artisan Beer Project
• Sameorganism,namecanmoreorlessbeusedinterchangeably
• Brettanomyces• Theasexualreproducing(budding)form,known
asananamorph
• Dekkera• Thesexualreproducingform,knownasateleomorph
• Originalnomenclature:– Brettanomycesbruxellensis– Brettanomyceslambicus– Brettanomycesintermedius– Brettanomycescustersii– Brettanomycesclaussenii– Brettanomycesanomalus– thelistgoeson…
Brettanomyces / Dekkera
• Currentnomenclature:– Brettanomycesbruxellensis*– Brettanomycesanomalus*– Brettanomycescustersianus– Brettanomycesnaardenensis– Brettanomycesnanus
andfortheperfectstate(teleomorph)– Dekkerabruxellensis– Dekkeraanomala
Ofthese,BrettanomycesbruxellensisandBrettanomycesanomalusarethetwospeciescurrentlyusedbybrewers,withaBrettanomycescustersianusjuststartingtomakeitswayintouse.
*B.lambicushassincebeenreclassiAiedasaB.bruxellensisandB.clausseniiasB.anomalus.
Brettanomyces / Dekkera
Initial Discovery and Characterization• Theearliestpublishedaccountcamefromapaperpresentedtothe
InstituteofBrewingin1904byN.HjelteClaussen.• HeproposedtheyeastbecalledBrettanomyces(BritishBrewingFungus),asitwasresponsibleforthesecondaryfermentationanddevelopmentofcharacteristic_lavorsandaromasofthe_inestEnglishstockales.
• In1940the_irstsystematicinvestigationwaspresentedbyM.T.J.Custers,andhis_indingson17strainsofBrettanomyces.
• AtthattimeCustersbelievedBrettanomycesyeastswereonlyfoundinEnglishandBelgianbeers,
• Wenowknowitisayeastthatisfoundaroundtheworldandineveryknownwinemakingregion.NOTaBelgianyeast..perse…
• CustersThesis• Fermentationofglucosetoethanoloccurredmorerapidlyunderaerobicconditionsthenanaerobicconditions,Custerstermedthis“negativePasteureffect”.• Thiswasinnomeansacompletefermentationbyabrewersstandards,onlymeasureofhowquicklyfermentationormetabolismstartedunderthestudiesconditions.
• Considerableamountsofaceticacidproducedduringaerobicconditions,whilenoappreciableamountswereformedduringanaerobicconditions.
• Custerstobelievedcellsslowlybecameadaptedtoanaerobicconditionseventuallyresultinginanormalanaerobicfermentation.
Custers Effect• Theterm“Custerseffect”waslaterintroducedinplaceofnegative
Pasteureffectandisbestinterpretedintermsofglycolyticactivity;• ascellsareswitchedfromaerobicconditionstoanaerobic,glycolysis(thebreakdownof
sugarstopyruvate)comestoatemporarystop.ThistransientlagphasewasobservedtolastuptotenhoursbeforetheslowdissimulationofglucoseandsubsequentproductionofCO2resumed.
• Lagphaseduringearlyanaerobicgrowthand/orfermentationisduetothecontinueddrainageofNAD+toNADHthroughanirreversibleconversionofacetaldehydetoaceticacid.
• Thereexistsaninabilityforthecellstorestoretheredoxbalanceviaproductionofreducedmetabolites,speci_icallyglycerol.– Thiscouldbeattributedtotheabsenceofglycerol3‐phosphatephosphataseactivityinsomeorall
Brettanomycesspecies.
• TheproductionofglycerolhasbeenshowntobeimportantinmetabolizingNADHandrestoringtheredoxbalanceduringanaerobicfermentationinotheryeastsincludingbrewersyeasts.• Glycerolproducedbyyeasthasasecondaryroleinenhancingtheperceptionofbodyand
mouthfeelinbeerwhen1‐2g/larepresent.Moreonthislater…
• TheslowadaptationofBrettanomycesyeastsmetabolismduringanaerobicconditionsfollowingthelagphasewasneverunderstood,althoughthe_indingsareinagreementwithmultiplestudiesthathavesuggestedanaerobicfermentationispossiblewithsluggishtoslowactivityinitially.
Fermentation Capabilities• Twouniqueandimportantenzymes.
• αglucosidase• Enzymecapableofhydrolyzing(breakingdown)wortdextrinswithup
to9degreesofpolymerization,amalto‐oligosaccharidecontaining9glucosemolecules.• Enzymefunctionsbycleavingoffaglucosemoleculeformingthenextlowermalto‐oligosaccharide.• BothextracellularandintracellularformsoftheenzymeareproducedbyBrettanomycesyeasts.• EnzymeresponsiblefortheoverattenuationobservedinLambicandSourbeers.
• βglucosidase• Enzymecapableofhydrolyzingmultiplesugarsandglycosidiccompoundsincluding;
• Lactose‐milksugar• Cellobiose‐sugarfromcelluloseinwood/plantmaterial• Glycosides‐presentinvariousHops,FruitandSpices
• EarlystudiesconductedatGuinessinDublinfoundstrainsofBrettanomycesclausseniiwereabletofermentlactoseandcellobiose.
• ResearchintoethanolproductionfoundaBrettanomycescustersiistrainthatwascapableoffermentingcellobiosetoethanol,andexhibitedahigherutilizationofcellobiosethenotherBrettanomycesclausseniistrainsusedinthestudy.
• PresentatvaryinglevelsinonlycertainBrettanomycesspecies.
• InterestinglyBrettanomycesyeastsaremostcommonlyculturedfrombeerconditionedinoakbarrelsandasymbioticrelationshiphasbeenassumedgiventhelongevityoftheirexistenceinthebarrels.
• StrangelyenoughmostoftheBrettanomycesspecieswhichdominateduringLambicbrewingdonotgenerallyhavethenecessaryβ‐glucosidaseenzymepresenttohydrolysecellobiose.
Production of Secondary Metabolites
• Mostsigni_icantaspectofBrettanomycesyeastsistheirabilitytoin_luencethe_lavorandaromaofbeer.
• Manyorganolepticdescriptorsexistincluding;clove,spicy,horsey,barnyard,smokey,medicinal,band‐aide,metallic,crackerbiscuit,goat‐like,catpiss,apple,_loral,tropicalfruitandcitrus.
• ResearchfromtheWineandBrewingindustrieshaveexplainedafewofthesecompounds• Precursorcompoundscomefromrawmaterialswiththeirproductionemphasizedor
limitedthroughbrewingtechniques.• Abilitytoproducevariousaromaticor_lavorcompoundsvariesgreatlybetweenstrains.
StrainDependent!
Volatile Phenolics• Responsibleforsomeofthemostrecognizedaromatic
characteristicsassociatedwithBrettanomyces• 4‐vinylguiacol–Clovelike• 4‐ethylguiacol–Spicy,Clove
• 4‐vinylphenol–Phenol,Plastic,Smokey• 4‐ethylphenol–Spicy,Smoky,Horsy
• 4‐vinylcatechol–Plastic,Bitter,Smoky• 4‐ethylcatechol–Band‐aide,Medicinal,Barnyard
• Appeartohaveasynergisticoradditiveeffectmakingtheirpresenceobservablewhiletheactualcompoundlevelsarebelowrecognizedthresholdlevels.
• Makesidentifyingonecompoundhardastheysharesimilarorganolepticcharacteristicsdependingontheamountpresentinabeer.
• Themechanismresponsibleforthemetabolismofthesevolatilephenolicsisatwoenzymesystem.
• Firstisaphenolic(cinnamic)aciddecarboxylase,• Responsibleforthedecarboxilationofhydroxycinnamicacidsintotherespective4‐vinyl
derivative• PresentinbothBrettanomycesandvariousbrewersyeaststrains
• Second,avinylphenolreductaseresponsibleforthereductionofthe4‐vinylderivativeintoitsrespective4‐ethylderivate.• ThevinylreductaseenzymeisuniquetoBrettanomycesyeasts
Production of Esters• EsterasespresentinBrettanomycesspecieshaveestersynthesizing
activitywithanincreaseofthefollowingestersobservedduringtheperiodBrettanomycesspeciesdominateasactiveyeastsinLambicandSourbeers.
• Ethylacetate‐Fruity,solventy• Ethyllactate‐Fruity,buttery• Phenethylacetate‐Rose_lowerlike
• Theesterasesdecreaseanyisoamylacetatepresent.
• HighconcentrationsofC8toC12fattyacidsaccumulateinLambicaswellduringthesameperiod.• TheseFattyacidsthenbecomeester_iedintotheirrespectiveethylesters.
• RecentlybrewershavetalkedaboutpineappleortropicalfruitlikearomasproducedbyBrettanomycesyeasts.• Unknownwhichcompoundsareresponsibleforthese_lavorsoraromas• Somepeoplehavesuggestedethyllactate,othersethylbutyrate.• Nostudiespreviouslylookedatarangeofestersproducedbypureculturesof
Brettanomycesyeastsbecauseupuntilrecentlyithasalmostexclusivelybeenconsideredaspoilageorganism.
Important Aroma / Flavor Compounds
Threshold Low/NotProduced• Ethylacetate(*onlyonestrain) Ethylacetate• Ethylcaproate‐C6fattyacidester Isoamylacetate
– Sweet,Fruity,Pineapple HigherAlcohols• Ethylcaprylate‐C8fattyacidester Diacetyl
– Musty,Pineapple,Fruity,Waxy Acetaldehyde
• Thingstotakeintoconsideration.
• Fermentationtype• Primaryfermentation• Hybrid/Mixedfermentation• Secondaryfermentation• Bottleconditioning
• RawMaterials• Flabby/Weakmouthfeel• Malt/Adjuncts• Hops• Fruit
• BrewingTechnique• Torestornottorest• Sourmashing/wort• Resttempandtime• Mashthickness• Spargetemp
• Nothingnewright?
How Crooked Stave Makes Brett Beers
AmericanBrettalescanbeverylighttoblackortakeonthecolorofaddedfruitsorotheringredients.Wood‐andbarrel‐agedsouralesareclassi_iedelsewhere.Lighttomoderateand/orfruityandcontributedbytheBrettanomycesyeast.Theevolutionofnaturalaciditydevelopsbalancedcomplexity.Horsey,goaty,leathery,phenolicandlighttomoderateand/orfruityacidiccharacterevolvedfromBrettanomycesorganismsmaybeevident,yetinbalancewithothercharacter.Aciditymayalsobecontributedtobybacteria,butmayormaynotdominate.Residual_lavorsthatcomefromliquidspreviouslyagedinabarrelsuchasbourbonorsherryshouldnotbepresent.Woodvesselsmaybeusedduringthefermentationandagingprocess,butwood‐derived_lavorssuchasvanillinmustnotbepresent.Indarkerversions,roastedmalt,caramel‐likeandchocolate‐likecharactersshouldbesubtleinboth_lavorandaroma.AmericanBrettalesmayhaveevidentfullrangeofhoparomaandhopbitternesswithafullrangeofbody.Esteryandfruity‐estercharactersareevident,sometimesmoderateandsometimesintense,yetbalanced.Diacetylandsweetcornlikedimethylsul_ide(DMS)shouldnotbeperceived.Chillhaze,bacteriaandyeast‐inducedhazeareallowableatlowtomediumlevelsatanytemperature.FruitedAmerican‐StyleBrettAleswillexhibitfruit_lavorsinharmoniousbalancewithothercharacters.OriginalGravity(°Plato)VarieswithstyleApparentExtract/FinalGravity(°Plato)VarieswithstyleAlcoholbyWeight(Volume)VarieswithstyleBitterness(IBU)VarieswithstyleColorSRM(EBC)Varieswithstyle
• BrewersAssociation,2011BeerStyleGuidelines,January10,2011
American-Style Brett Ale
• Ideconstructmybeersfrom_inishtostartbycomingupwiththe_inishedcreationandworkingbackwards.
• OnceIknowwhatIwantthebeertolook,smellandtastelike,it’seasiertochoosetheingredients/brewingtechniquesthatwillhelptocreatethe_inalproduct.
• Ifitis“cleaner”BrettanomycescharacteristicsI’mafter,subtlefruityaromas,orlightclovewithaslighttartness,thenPrimaryfermentationwithBrettwouldbethechoice.
• IfI’mafteramorefunkybeerwithstrongercomplexcharacteristicsgainedthroughextendedaging,secondaryfermentationwouldbethechoice,possiblyinabarrel.
• Amixedfermentationcangivethebestofboth..yeastwithfruityestersfromachosenSaccharomycesstrainsaswellasgoodattentionquicklywhiletheBrettanomycesstraindeliversmoreprimarytypecharacteristicsupfrontaswellasdeliveringonthebackendduringextendedaging.
• It’snotblackandwhiteandtherearemanycombinationstoplaywith.Intheenditwillcomedowntotherawmaterials,BrewingtechniquesandBrettanomycesstrain(s)chosen.
Brewing with Brettanomyces
Quality Control
• Useseparatelymarkeddesignatedequipment• AsyouretireequipmentuseitasBrettanomycesandsourbrewingequipment
• Brettanomycesisnotasuperorganism,itisayeastandcanbecleanedandremovedlikeyeast.Heatkillingorsterilizingwilldothetrick
• Recommendedmediaagars
MYPG(Maltextract)agar WLNagar CuSO4agar
Propagation
• IwouldhighlyrecommendpropagatingupanactivestarterifusingBrettanomycesyeastforprimaryfermentation.• Propercellcountsneededforprimary• Propercellphysiologywillleadtoahealthyactivefermentation• Higherviabilityandvitality
• SametechniquesusedtogrowSaccharomycescanbeusedwithBrettanomyces,onlymoretimeisneeded.• 24hourlagphase• 3daysofexponentialgrowth• 1‐2daylagorslowedgrowth• 2‐3daysofnearexponentialgrowth• Generallytook7‐8daystoreachstationaryphase
• Equipmentneeded• 1litreErlenmeyer_lask• Sterilebreathablefoam/_ilmtocover_lask(stillneedtheexchangeofO2andCO2)• Warmenvironment(80°Fisnice)• Stirplatewillmaximizecellcounts(giveagoodswirldailyoroftenifyoudon’thaveastirplate)• Lightlyhoppedwortof12°Platoor1.048Gravity
Batch Culture Growth Curve
• “Clean”primaryfermentation• Brettprimaryfermentedbeerthatdoesnotuseanysouringorganismorsourmashing.• Fermentationtakesbetween2weeksand1month.Straindependent• Littletonoperceivedtartnessasanaerobicfermentationdoesnottypicallyproducelevels
ofacidsabovethreshold.• CoulddevelopaslighttartnessfromminimalaceticacidproducedbytheBrettaftersome
extendedagingorheavyoxygenatingatknockout.
• “Sour”primaryfermentation• Brettprimaryfermentedbeerthateitherhadasourmash,orsouringorganismswhich
developduringprimaryandwithtimeandaging.• AcidultedmaltisanotheroptionandI’veheardofbrewersusing10%ormoreinthemash• CanbeagoodideaasthereseemstobeasymbioticrelationshipwithBrettandLacticacid
bacteria• Appearstoimproveattenuationandlowerfermentationtime.• Fermentationtimestill10daysto1onemonth.Straindependent• MostpeopleassociateBrettwithtart/sourbeers.
Primary Fermentation
• Iknockoutat68°F(20°C)andletfermentationrampupto72°F(22°C)• Iprefertokeepthefermentationaround70°F(20‐22°C)forastablesustained
fermentation
• Iliketoheavilyoxygenateatknockout‐Alwaysoxygenate!• Estimateddissolvedoxygenof12‐15pmm• IncreasesO2andincreasesaceticacidproduction• Ilikeaslightaceticcharacterasat45‐150ppmaceticisasoftandsweetacid,very
complimentarytothebeer
• Pitchingrateof1×106cell/ml/°Plato• Thisisthestandardruleofthumbpitchingrateforaleyeast
• 14°Plato(1.056)beerattenuatesdownto2.5°P(1.010)in7‐10days
• Fasterfermentationtimewhenre‐pitchingwithsuccessivegenerations• Greaterabilitytofermenthighgravitybeers
• 22°Pbeerattenuateddownto4°Pin10days
Primary Fermentation
• Minuteamountsofoxygenduringfermentationinbene_icialinstimulatingfermentation.
• CanhaveaheavyH2Saromaforsometimeifnotabletobreathe
Oak Barrel Primary Fermentation
• Acidulatedmalt,SourMash,SourWort
• Pre‐souringwortwithlacticacidleadstobetterattenuationinagreaterrangeofBrettanomycesstrains.
• Increases_lavorcompoundsandaddsdepthmaybeevencomplexity• Bothethylacetateandethyllactateincreasedasthelacticacidconcentrationincreased,especiallyethyllactate(go_igure).
• Esterslikeethylcaproateandethylcaprylatesawadecreaseinproductionwhilehigheralcoholsincreasedslightly.
• Anincreaseinhigheralcoholsisprobablyduetotheincreaseinattenuation.
• Conclusion• LacticacidappearstoincreaseattenuationinBrettanomycesyeasts.• Asourmashorsomeacidulatedmaltinthegristcouldbebene_icial.• Toomuchacidandtheestersethylcaproateandethylcaprylatewhichareprobably
responsibleforthefruity,pineapple,_loral,tropicalfruit,andsweetaromas/_lavorsdecrease.
• Inour_irstcommercialbatchwedroppedthepHto4.5tostartprimary,it_inishedinunder3weeks.
• Mostrecentsourwortbatchdroppedfrom10°Pto1.5°Pin9days.Lotsoftropicalfruitaromaand_lavor
• Cautionifmakingsourwort…droppHto4.5beforeKO,KO@120°Fandsustainaround100°forafewdays,DoNotoxygenate…PurgewithCO2throughwort.Pitchaculture..Youcanre‐boilaftertokillthelacto.
Benefits of Pre-soured Wort
Impact of Pre-souring Wort• Furtheranalysisconcentratedonthechangesinfermentationbehavior
duetopre‐souringwortwithlacticacid.Wortwasacidi_iedwithaninitiallacticacidconcentrationof
100mg/l,startingpHof4.55 500mg/l,startingpHof4.051,000mg/l,startingpHof3.75 3,0000mg/l,startingpHof3.08
• ThisisthesameideaaswithSaisonmixedfermentations.• Oneyeastisusedtogetthedesired_lavorsandtheotherforattenuation.
• Saccharomycesprimaryforafewdays,thenpitchBrettanomyceswhiletheactivefermentationisstillgoing.Moresimilartosecondaryfermentation.• CouldalsounderpitchinprimarywithSaccharomycesstrain,thenwhenfermentationslows,rackofftheyeastandtransfertoanothertankwithalargepitchofBrettanomycesto_inishoutfermentation.
• Brettanomycesyeastpitched_irstfortheprimaryandafterpitchSaccharomycesto_inishoutandattenuatethefermentation.• Improvesmouthfeeldependingonthestrainchosen
• Mixedfermentation• PitchbothBrettanomycesandSaccharomycesatthesametimeleteachonedoitsthing..
• RelativelycleanBrettcharacterdevelopsafterafewweeks.
• Oncefermentationiscompleteit’sgoodtorackthebeerofftheyeast(s)andmaturethebeerwithonlytheyeastsinsolution.MostlyBrettasit’snottoo_locculentatroomtemps.
Hybrid/Mixed Fermentation
• MostpopularuseofBrettanomycesisinsecondaryfermentations.
• Canaddmorecomplexityoranewdirectiontoabeer.
• Afewfactorstoconsider• Assesswhatchangesarelikelytotakeplaceandhowitwillaffectthebeer.• Residualsugars
• ResearchconductedonsecondaryfermentationswiththesameeightstrainsofBrettanomyces,showedadecreaseinbothmaltoseandmaltotriose.
• Thebeersstartedwithagravityof2.5°P(1.0093)andsawfurtherattenuationbetween1.8°P(1.0062)and0.9°P(1.003)
• Maltosedecreasedfrom5g/lresidualsugarto<1g/lsometimesaslowas0.1g/l.• Maltotriosedecreasedfrom7g/lresidualsugartobetween4and2g/l.
• Ingeneralit’simportanttohavesomeextradextrinsinthebeeraswellasaspecialtymaltsoradjunctsthatcontributetobodyotherwisethebeercanturnoutwateryand_labby,lackingdepth.
• AtthesametimeI’mnotafanoftakingabadbeerthatdidn’tfermentoutandhadfermentationissuesandtossingBrettanomycesatittoseewhathappens.Won’tmakethebestbeer,onlyforsomethinginterestingatbest…
Secondary Fermentation
• Extractionofpolyphenolsandhydroxycinnimicacidsfromthemash.
• HigherlevelsinSecondaryfermentationsthanPrimaryfermentation.• Hydroxycinnimicacidsarepresentinthecellwallsandcellswhichmakeupthe
aleuronelayerandthehusk.• Proteinrestwillcreatethepre‐cursers.• Excessivehandlingofthemalt/mashcouldimpartsomeofthesecompounds.• Carefulwithoverspargingandspargingtoohot.• Somewillboiloffinthemash,butwhatisleftbehindcanleaveaggressive_lavors
afterSaccharomycesalongandBrettanomycesdotheirthing.• InsecondaryafterusingaPOF+Saccharomycesstrainthe4‐vinylcompoundswill
alreadybepresent.
• Italwaysbeenmyphilosophytolimitthephenoliccharacteristicsofthesebeers.
• Somebrewerslikethem,andpurposelymashtogetthepre‐cursersandcreatespicy,smoky_lavors.• Ferulicacidrestatabout109‐111°For43‐44°C..
Secondary Fermentation
• PitchingrateinSecondaryfermentations
• Brewershavetheirtheorieswhyahighpitchcountproducesmore_lavorandaromaandotherBrewerswilltellyouthatlowerpitchcountswillproducemore_lavorandaromas.
• Researchwitheightstrainsshowedvariabilityfromstraintostrain.Sometimeshigherpitchcountsloweredhigheralcohols,sometimestheyraisedthem.Samewastrueforesters.
• Ihavenotfoundmuchofacorrelatedeffectonoverattenuationeither.
• Don’taddtoomuchBrettanomycesyeastslurryotherwiseyou’rejustblendinginBrettanomyces_lavor,createdduringthepropagation.• HighinAceticAcid.
• Generalcellcountstoaddinsecondarycanbeanywherefrom500,000cells/mlto2,000,000cells/ml.
Secondary Fermentation
• PopulartechniquetogettheBrettcharacterbyaddingtheyeastinthebottlingbucket.Needextrasetsofallgasketsandporousmaterialonthebottle_iller.• Bestpracticeistohaveasecondbottlingunit,unlessyoudon’tmindallyourbeers
possiblyhavingBrett.
• Canbeusedtoputthe_inaltouchonabeerandallowforalightintegratedBrettanomycescharacterinsteadofaBrettbomb.
• Seewhat100,000cells/mlcandotoabeerinbottleconditioning.• Timetoreachthedesiredcharacterwillbestraindependent.NewBelgiumistypicallytwoweeks,otherstake3months.
• CarefulovertimeasautolysisoccursinSaccharomyces,treheloseisreleasedwhichisafermentablesugarforBrettanomycesandfurthercarbonationwilloccur.
• Ithasalsobeensuggestedthatun_ilteredbeerswherethereisalargeportionofSaccharomycesincontactwithBrettanomyceswillproducegoatyaromasduetocaproic,caprylicandcapricacidsreleasedfromthecellwallofSaccharomyces.• Brettanomycescouldturnsthoseacidsintoestersthenovertime.• Wouldneedtositonthebeerafterbottlingtodeveloptheseesters.
• Goodpracticeistoletthebeerdropbrightor_ilterbeforesecondaryunlessyouwantthesearomasand_lavors.
Bottle Conditioning
• DevelopingabeerthatwillbefermentedwithBrettanomycesinvolvesdevelopingarecipethatwillstanduptotheyeast.
• Noonesetsouttomakea_labbybeeroronelackingaromaand_lavor,butcanbethecasewithBrettanomycesfermentedbeers.• Usuallyassociatedwithdrynessduetooverattenuation.
• Notexactlythecase…
• OnereasonwhyBrettanomycesissucha_ickleorganismisduetothelagphaseseenwhenswitchingfromaerobictoanaerobicconditions.ThisisduetotheinabilitytorestoretheredoxbalancebetweenNAD+andNADH.Thisisappearstobecausedbythelackofglycerolproductionduringfermentation,ametabolicstepwhichactstorestorethebalance.
• Glycerolproducedbyyeasthasasecondaryroleinenhancingtheperceptionofbodyandmouthfeelinbeerwhen1‐2g/larepresent.
• Somestudieshaveobservedslightglycerolproductionoccurringunderanaerobicconditionsinavariableamountofstrains.
• Glycerolproductionbetweenstrainscouldindicatetheabilityoftheredoxtoberestoredmorerapidly,inwhichcasestrainswouldlikelybecapableoffullfermentationwithadecreaseinthetimerequired.
RawMaterials
• Bodyandtheoverallbeerpro_ilehavetobebuilttosuittheBrettanomycesyeastsandtheirabilitytooverattenuateaswellasthelackofglycerolproduction.
• Bodycanalsobetakencareofinthebrewhouse.• Mashinginatahighertemp• Lowermashresttime• Bothcouldfavoralongerendtofermentation,Ifyou’relookingtomakeabeerthatisreadyforbottlingsoonerthesetechniquesmightnotbethebest
• Adjuncts• Oats‐IpreferSteel‐cutoats,givesasilky,creamymouthfeel,light_lavorcontribution.
• FlakedWheat‐Addsmorecomplexstarches,highproteinlevel,couldaidheadretention.
• Cara(pils)(hell)(foam)‐supposedtoaidheadretentionaswellasbuildbodyinbeer,little_lavororcolorpick‐up.
• Rye‐canaddanicecharacterat5‐10%ofthegrist.• Spelt‐Suggestedforpuremouthfeeladdition.
• Acidulatedmalt• I’veheardofusagesupto10%whichgiveaverynicelacticacidity.• Aciditycreatesmouthfeel,possibilitiesfornew_lavors/aromas,• Coulddoasourmash,orsourthewort.
RawMaterials
• PrimaryfermentationwithBrettanomycescancreaterelativelycleanbeers.Eachstrainwillhaveitsowncharacteristic_lavorsandaromasbutmuchcanbedonetoenhancetheappealofthosecharacteristicsandenhancetheBrettanomycestypearomas.
• ViennaandMunichmakeanicecontributionontopofthebasemalt.• CaraVienna,CaraMunich,CaraAroma,Carmel,Honey,SpecialB–allthesemaltscanadd
anicecharacterinaBrettbeer.• Carefulaboutaddingmaltswhichincreasethebready_lavor/aromaasBrettanomyceswillcreatetheseonitsown.
• Roastedmalts–I_indadarkBrettbeertobequitecomplex,lotsofaromasand_lavorsdevelop.• ConsiderdebitteredofdehuskedmaltslikeCarafaspecialI,II,orIII.• Toomuchroastedmaltcharacterbringsoutastringencyanddoesn’tworkwellwithsomeBrettnomycesstrainswhichcanhaveametallicastringentcharacter.
• Hops• Brettanomycescandosomeveryinterestingthingswitharomatichopglycosidecompounds.
• Brettaromascanbecomplimentedbyaromatichopswithfruity,spicey,piney,andcitrustypearomas.
Flavor/Aroma Contributed From Malts
• Singleinfusionmash‐notsurethereisanythingtobegainedbyastepmash.
• Ferulicacid‐pre‐curserfor4‐vinylguiacoland4‐ethylguaicol• Wantspicy,smokey,phenoliccharacteristics?
• Ferulicacidrestat43‐44°C(109‐111°F)enzymesreleaseferulicacidandotherhydroxycinnamicacidsintothemash
• MashTemp‐65‐67°C(150‐153°F)adequateconversionwithhighlymodi_iedmalts,largestarchgranulegelatinization.
• Mashrest‐30minutes,enoughtimeforconversion.• Re‐circ(vorlauf)tillsolidsarecleared
• Mashthickness‐Ilike2.5:1liquortogristratio(Liters:Kilograms)• Toohighpromotesdryness.
• Sparging‐Tohotofaspargetempextractshuskandtannin_lavorsaswellasoversparging.• Createsastringencyandthepossibilityforphenolicpre‐curserstobeleachedintothewort
• 168°F(75°C)willdothejob• Finalrunningdependsonthebeerbutdon’tgobelow2‐3°P
Brewing Techniques
Questions?
www.crookedstave.comwww.brettanomycesproject.com