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?

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