Tài liệu Imperial IPA: History, Brewing Techniques, Style Evolution. docx

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ImperialIPA:
History,BrewingTechniques,StyleEvolution.
/>NathanSmith<>
TheBrewingNetworkSundaySession
www.thebrewingnetwork.com
July6
th
,2008
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ImperialIPA‐ Outline
• Introduction
• History
• CommercialExamples
• ExampleRecipes
• Keybrewingpoints
• StyleEvolution
• References
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ImperialIPA
Introduction
•IntenselyhoppyverystrongAmericanPaleAle.
• RelatedtoAmericanBarleywine;withoutbig/deepmaltflavorandsweetness.
•Hopsatalllevels,yetclean,drinkable;notaheavysippingbeer.
•Ashowcaseforhops,especiallynewhighalphaAmericanvarieties.
•“TheSUVofbeers” KevinPratt,BJCPGrandMasterI.
•BJCPcategory14Chighlights:
•Aroma:Intensehoparoma(cirtus,resin,floral,low/nograssy),lowcleanmaltsweetness,low/noesters,
low/noalcohol.Nodiacetyl.

• Appearance:Goldenambertomediumreddishcopper.Cleartohazy.Goodoff‐whitefoamstand.
•Flavor:Strong,complexhopflavor.Hightoabsurdlyhighhopbitternessbalancedwithmaltbackbone.
Lowto
mediumcleanmaltflavor;lowcaramel/toastOK.Nodiacetyl.Low/nofruityesters.Long
lingeringbitternessinaftertaste.Mediumdrytodryfinish.Cleansmoothalcoholflavor.Oakis
inappropriate.SlightsulfurOK,notcommon.
• Mouthfeel:Mediumlighttomediumbody.Nohopastringency.Moderatetohighcarbonation.Medium
to
lowalcoholwarming.
•OG:1.070‐1.090,FG:1.010‐1.020,IBU:60‐120,SRM:8‐15,ABV:7.5‐10%
• AStylethatisstillevolvingandchanging!
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EnglishIPAhistory1800s
•FirstbeerbrewedspecificallyforexporttoIndiabrewedbyGeorgeHodgsonin
London,1790(4).
• Hodgsonmonopolized theIndiaAleexportbusinessuntilapproximately1820(4).
• Accordingtolegend,awreckedcargoin1827offtheportofLiverpoolofBass’
EastIndiaPaleAlewasrescuedand found greatfavorwiththelocalsthusmaking
itavailabletotheEnglishnon‐military.
• IndiaAleHoppingratesprobablyaddedup to45to60IBU's (3).
• Hodgson’sIndiaAlehoppedatarateof10.5oz.PerUS5gallons,approximately70
ouncesperUSbarrel.(4).
• Multiplehopadditions andlimitedcontacttimewerecommon
duringwort
production:hopsonlykeptinwort for30minutesbeforebeingremoved,4
separatechargestotalanda2hourboil.
• IndiaAleinthe1800swasprobablya7 ‐8%beeratthetimeofexporttoIndia.
•Considerableevidenceexistsintheformofsalesreceiptsandstorage
manifests

thattheproductwaswatered downuponarrivalbeforeconsumption.
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Amercan IPAtoImperialIPA
1994‐1999
• FirstmoderncommercialexamplefromVinnieCilurzo.InauguralbrewatBlindPigin
Temecula,CAJune1994.AgedinOakfor9monthsandfirstservedatthebrewery’sfirst
anniversary.Becameanannualanniversarybrewthereafter(10).
•”OurbrewwasalowerABVdoubleIPA,onlylike6.60%,wedoubled thehopsandraisedthemaltbyalittle. Itwasso
bitteritwaslikelickingtherustoffatincan. WithsuchalowABVthehopsreallycamethrough.” – VinnieCilurzo
• RougeI2PAdebutedattheOregonBrewer’sFestivalin1996.
• StoneSecondAnniversaryAle,1998.
• Eugene,OR1998SpringBeerFestivalStyle:ImperialIPA(10).
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Blind Ping 2
nd
Anniversary 1995
Rogue I2PA 1996
Stone 2
nd
Anniversary 1998
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ImperialIPA
GABFCommercialExamples
• 2001GABF:SteelheadHopasaurus Rex‐ Gold,otherStrongAlescategory
• FirstappearedasseparateGABFcategory,40in2003.
• PizzaPortFrank(gold2003‐ silver2004)
• RussianRiverPlinytheElder(GABFgold2005‐2006,Bronze2007)
• Moylan’sHopsickle (gold2007)
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Russian River Pliny the Elder, 2008Pizza Port Frank, 2003
Moylan’s Hopsickle
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ImperialIPA
BJCPexamples
• Firstappearedinthe2004guidelines,Category14C.
• CommercialExamplesfromthe2008guidelines:
•ThreeFloyd’sDreadnaught,AveryMaharaja,Bell’sHopSlam,StoneRuination,GreatDivide
HerculesDoubleIPA,SurlyFurious,RogueI2PA,DogfishHead90Minute,VictoryHop
Wallop.
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Three Floyds Dreadnaught
Dogfish Head 90 Minute
(Original bottle)
Avery Maharaja
Rogue I2PA (current bottle)
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ImperialIPA
ExampleRecipes
• Homebrewtake‐offsonPlinytheElder
• Nathan’srecipe:onthelowerOG/FGendofthestylewithaSummitkick.
– />• McDole’s recipe:onthehigherOG/FGendofthestylewithaNorthern
Brewerkick.
– />• Considerusingtheseasastartingpoint,thenexperimentandmakeit
yourown.
• Adapttoyourownequipment,rawmaterials,techniques,preferences.
• Lotsofroomforcreativity.
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ImperialIPA

BrewingTips–Water
• ExcessMagnesiumcancausenonhop‐derivedastringentbitterness.
• Sulfateinmoderateamountscanlendacrisp,dryfinish.Inhighamounts,
itcanhaveaharsh,saltyflavorandnegativelyimpacthoputilization.
• Highcarbonatewatercangiveanimpressionofharshhopbitterness;not
tomentionnegativecolor
impact,poorprotein/tanninseparation during
hot/coldbreak.Becarefulwithconcentrationsexceeding50ppm.
• Low/moderateChloride(fromCaCl,MgCl)canroundness,fullnesson
palate.Over400ppmCl canhaveapastyflavor,over500ppmitcan
negativelyinfluenceyeastactivity.
• Ifyou’readjustingforCaalready,considerCaSO4,CaCl ora blendofthe
two.
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ImperialIPA
BrewingTips–Maltandmashing
• 70‐80%Basemalt:Domestic2‐rowpalemajority,smallamountsofMaris
Otter,Vienna,Munich,Pils OK.1%WheatOK.
• 5‐10%dextrinmalts:DomesticCrystal10‐40,Briess Carapils,Experiment
with1‐2%Higherkilnedcrystal(60‐80L)ormaybeevenatouchofa
roastedmalt.Otherpossibilities:Victory,
amber,speical roast.
• Only2‐rowmalt,nospecialtymalts:RogueI2PA,Dogfish90minute.
• “Toomuchcrystalmaltmuddiesupthehopflavors,uselower%of crystal
maltsforacrisp,cleanhopflavor.Crystalmaltclasheswithbitterhop
flavors.1%crystalmaltontheElder,0%crystalmalton
theYounger”
(VinnieCilurzo,TBN8/14/20052:01:37).
• 5‐15%Simplesugar(corn,turbinado)todryoutthebeer,consideramash

temperaturethatpromotesbeta‐amylaseenzymeactivity(148‐152F).
• MonitorpHcarefullytoavoidpolyphenol extractionduringmash&
sparge.
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•Hopsatalllevels
• Consider:Mash,Sparge (FWH),Allstagesoftheboil,justbeforecooling(hopback),just
aftercooling,dryhopping(afterfermentation),atserving(dry hoppingintank,Randall).
•Less‐commonmethods
•Mashhoppingand/orFirstWort hopping
•Moresuccessfulinlowhoppedbeersandwithhopsthathaveahighhumulene
content(9).
• Suggestedhopadditionrateforfirstwort hoppingis30%ofthetotalkettle
program(aromaadditions)withoutfurtheradjustment(9).
•TomO’Brien–Oneofthefirsthomebrewers creditedwithhoppingthehotliquor
tank.
ImperialIPA
BrewingTips– Hopadditions
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Hop back, side view
(morebeer.com)
Hop back, top view
(morebeer.com)
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ImperialIPA
BrewingTips–Hopselection
•Americanhighalphaacidrecommendedforalladditions,blendfor
complexityandconsistency.
•Forbittering IBUs– Use70‐80%lowcohumulone suchasWarrior,
MagnumorHorizon;20‐30%roughcitrus,pepperorpinebittering hop

suchasChinook,Columbusforsomecomplexity(VinnieTBN8/13/2005
2:00:32)
•Oilcontentandaromaticqualityimportanceproportionalto
howlatein
theprocessthehopisbeingused.
•Makehopteaofunknownvarietiestoevaluateflavorandaroma
qualities.
•Don’tbeafraidtoexplore.Example:Hersbrucker usedinAlpineBrewing
PureHoppiness.
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ImperialIPA‐ Hoparomaandflavor
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ImperialIPA
BrewingTips– Hopformats
•Flowers–quickdeterioration,toughtostore,lupulin inpurestform–
slowerreleaseofhopoils,“alittlemoresoft,wellrounded” (10).
•Plugs–Middlegroundbetweenflowersandpellets.Veryfew,ifany
varietiesavailablecommonlytohomebrewers.
•Pellets–Stable,lowoxygen,goodstorage,pressureduringproduction
createsheat,oxidizessomecompounds,oil
loss.Rupturedlupulin glands,
alittlemoredirect&Inyourface.Quickreleaseofacidsand potential
volatilizationofoils.Pellethopscanoxidizemorerapidlythanwhole(9).
Non ruptured Lupulin Glands (14) Ruptured Lupulin Gland (14)
Whole Flower, Split (14)
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ImperialIPA
BrewingTips– Hopextract

•HopextractsAdvantages:reducedcost,storedatroomtemperature,increased
utilization,consistency,downstreamapplications(post fermentation),micro
stability.Andwithmodifiedhopextracts,improvedfoamcharacteristicsandlight
stability(9).
•Hopextractsdisadvantages:flavormatching,wholehopcharacter (aroma)canbe
difficult(9).
•WorldProduction%breakdown,2005 estimate:35%extracts,
35%pellets,10%
wholehops,25%isomerized and reducedproducts(13).
Geir Ove Grønmo, Oslo, Norway

CO2 hop extract from

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ImperialIPA
BrewingTips–DryHopping
• Dryhopping=extractionofhopoils.EssentialfortheImperialIPAstyle.
• Multipledryhops,uselessateachdryhoppingstage,butdryhopmorefrequently
•Biggeraroma,Longerlastingaroma,Closerto“stickingyourheadinabagoffreshhops”
(7).
• PlinytheYounger–Onenewdryhopaddedeachweek,4dryhopstotalovera4week
period(7).
• Dryhopafterpullingtheyeast.
• Dryhopwarm(60‐68F).
• RussianRiver–Blendofpelletandflowers,flowersusedmorecommonlyatthe
endofthedryhoppingprocess(7).
• Recirculationorrousingthefermenter duringdryhoppingtohelppromote
extractionofoils(7).
•Useolderhopsforhotsideandnewerhopsforcoldside(9).
•Pullthehopsoutofthebottomoftheconeinaconicalateach dryhoppingstage

(7).
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ImperialIPA
BrewingTips–DryHopping
•Youcandefinitelyoverdryhop:Harsh,vegetative,tannicflavorsandaromas(7).
•Morearomaticswithashortercontacttime5‐7daysmaxiumum (7).
•FirestoneWalkeronlydry‐hops5daysmaximum,RussianRiver=5daydryhop
minimum(7).
•FordryhoppingsuggestedthatT‐45pelletsgivelowervegetative
matterandthe
necessarycontacttimeisreduced(9).
•FirestoneWalkertheoryondryhopping:
• selectionofbest(newcropyear)aromavarieties;
• blendinghopsforconsistencyandcomplexity;
• extractionisbetteratelevatedtemperatures;
•emphasisonlowdissolvedoxygen(DO);
•removalofyeastplugpriortodryhopping;
• rousingwithCO2tohelpcontrolDO;shortcontacttime(3‐4days);sanitarytechnique;
• blendingof
beersatfinish(9).
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ImperialIPA
Brewingtips–Dryhopping
•Dryhoppinginthekeg
• Screenorfilterontheendofthediptube.
•Hooksorhandlesontheinsideoftheservingtanktoholdahop bag:RussianRiver
Youngerishoppedintheservingtankusingthismethod.
•Post‐kegdryhopping=Randall.EastCoastvs.WestCoast

rivalryamongstprofessional
brewers.
– BuildyourownfromGeir Ove Grønmo,Oslo,Norway
• />Corny Keg Lid with hop bag
hook (morebeer.com)
Carboy hop weight
Randall
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ImperialIPA
HopChemistry
•Aromaticcompoundsboundtoglucosewhichmaybereleasedlater. Thisprocessreferred
toasglucanization.ResearchbyTomShellhammer atUCDavis.
• Hopscontainthousandsofchemicals:DuringGaschromatographyanalysisofhopsat45
minutesofretentiontimetheprocessisstillidentifyingcompounds(Colin,BrewingNetwork
wethopshow10/21/2007
1:13:00).
• MaximumIBUfora5%beer=120ppm=80IBU(12).
• Asalcoholandunfermentedcarbohydrateinthebeerincreases,sodoestheabilityofthe
beertocarrymoreIBU.Somebarleywinesmayhaveover100IBU. (12),MitchSteele.
• Otherconsiderations:LargeamountsofIsoalpha acidadherestothe
yeastcell;measured
IBUgoesupwhilepercieved bitternessgoesdownduetodissolutionofalphaacids(9).
• 5.4pHforwort andsubsequentbeerdeterminedasoptimalpHforbestbitternesscharacter
(5.2foroverallstability).
• After90minutesofboling,iso‐alphaacidsstarttobreakdowntoHumulonic acid(9).
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ImperialIPA
HopOils:FlavorsandAromas
• Monoterpenoids (associatedwithfreshdryhoparoma)(9)

•Myrcene:spicy,petroleum
• Linalool:floral,citrus
• Geraniol:floral,rose
• Limonene:citrus,fruity
• Terpineol:woody,resinous
• Nerolidol:rose,apple,woody
•Beta‐Pinene:spicy,piney
•Cirtral:citrus,lemon
• Cadinene:citrus
• Sesquiterpenoids (whenoxidized,associatedwithnoblehoparoma),
woody,resin‐like.(9)
• Alpha‐Humulene
•Beta‐Caryophyllene
•Beta‐Farnesene
• Humulene Epoxide
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ImperialIPA
FermentationConsiderations
• YeastSelection:Clean,neutralCaliforniaAleyeastrecommended.
– Wyeast 1056orWhiteLabs001.
• Hop‐likefermentationbyproducts:
– Appleester:Ethylalcohol+aceticacid=ethylacetate(13).
– Pearester:Hexyl alcohol+aceticacid=hexyl acetate(13).
– Pineappleester:Ethylalcohol+butyricacid =ethylbutyrate(13).
• LimonenefromhopsandH
2
Sfromfermentationgivesadistinctgrapefruit 
aroma.Limonenecontent=grapefruitaromaintensityinthefinished
beer.SierraNevadaBrewingCompany(14).

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ImperialIPA
FermentationSchedule
• Example:RussianRiverWLP001Fermentationanddryhopschedule(7).
– WhiteLabs0016‐7daysprimary68F,sealup thetank,sitfor24hours.
– diacetyl restat68F,dropthetemperatureto52Ffor2daystopullthe yeast
out.001hastroubledroppingoutattemperaturesabove52F.
– Directcorrelationonmorearomaandlessyeastinsolution
when dry
hopping.
– Pullasmuchyeastashasflocculatedoutofthe bottomoftheconical,dothe
firstdryhop.
– shutoffglycoltoletthetemperatureslowlyrisebackupto68F.
– 12daydryhoptotalonPlinytheElder;RRIPA=6dayswarm,
Elder=10days
warm.
– 2daysbeforetransferring,temperaturedroppedto32Ftogetthehopsto
settleout(IPAandESBthishappensatday8,Elder,thishappensatday12)
(7).
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ImperialIPA
Evaluation
• Freshconsumptioncriticaltoinsurethatthevolatilehoparoma andflavor
ispresent.
• Don’tletthisbeersitwarm,beverycarefulwithlightandO2exposure.
• MikeMcDole’s 6weekuntilpeakrecommendation.
• Minimumof100mLtogetaccuratehopinterpretationtobeableto
discernadhumulone/cohumulone bitterness;Corvalis Hop
convention/summit(Colin

Kaminski.,10/21/2007TBNshow).
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ImperialIPA
StyleEvolution‐ What’snextforhoppybeers?
• SmallIPAs
– McDole’s TinyPliny
– 21
st
AmendmentBitterAmerican.3.6%ABV,40IBU
• Herb/spicechemicalcompoundflavormatching
• Rosemary:myrcene,pinene
• GrainsofParadise:caryophyllene,humulene,linalool
• Coriander:limonene,pinene,linalool
• NewUShops(RalphOlson,HopUnion,Hopshort a geTBNshow9/2007):
•Glacier(Fuggle‐like)– Willammette,Tettnang,Styrian Golding5.5%AA,Lowcohumulon e, good
yield,highMyrcene.
• Sterling– Saaz andMt.Hoodhybrid.Saaz‐likereplacement.6‐9%AA.
• Apollo– Unknown
• Palisade(MildCascade‐like)‐ YakimaChiefproprietary5.5‐9.5%AA,lowmyrcene,20%
humulene.
•OthernewhopsoutoftheSimcoe/Ahtanum programatYakimaChief?
• Nontraditionalyeast‐ BelgianAleYeast
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References
1. 2008BJCPguidelines,www.bjcp.org
2. Brewer’sAssociation />3. LondonandCountryBrewer,SecondEdition. PrintedforMelliurs FoxattheHalfMoonandSeven
Stars,WestminsterHall,1736.
4. PaleAle,SecondEdition.TerryFoster,Brewer’sPublications,1999.

5. KevinPratt,Emailconversations.
6. PorterMythsandMysteriesBreweryHistory112pp.31‐40‐
/>7. TheBrewingNetwork6/26/2005VinnieCilurzo dryhopping
lecturefromtheBaltimore,MDNHC
2005.
8. VinnieCilurzo,Emailconversations.
9. TheNewBrewerVolume23,Number6.“TheEternalQuestfortheUltimateHopImpact” byMatthew
R.Brynildson (p.22‐29)
10. TheNewBrewerVolume21,Number1.“DoubleIPAs CreateAWholeNewCatego ryIntheHumulone
Derby” byJimParker(p.28‐33)
11. />12. “FortheLoveofHops” StanHieronymusAllAboutBeerMagazine,Volume24Number6,January
2004 />13. “Humulus Lupulus:HoppingforFlavorandAroma” MatthewR.Brynildson, MichiganBrewersGuild
andMBAADistrictMichiganWinterConference
25DOZEStyleTalk‐ ImperialIPA‐ 6/30/2008