1. DARK SIDE IMPERIAL
STOUT
Lab Report #3
Dane Hoffman
FTEC 460

2. Name ofBrewer: Dane Hoffman
Name ofBeer: Dark Side Imperial Stout
Style of Beer: Imperial Stout
Brew Date: November6th
, 2015
KeggingDate/ Tapping Date: December2nd
, 2015
Batch Volume:40 Liters
Original Gravity = 18.2
Final Gravity = 3.96
Section#1 Calculations
Calculation#1 IBU’s
IBU = [W(grams) xAA(%) x U (%) x 1000]/ Volume (liters) Foreach hop edition
11.3 IBU’s= 21.0 g * (.11) * (.24) * 1000/ 49L
Calculation#2 ABV= (OG (plato) – FG (plato)) * .516
7.35 % = (18.2 -3.96) *.516
Calculation#3 Yeast Pitch Volume
(1.8*10⁷*49 Liters)/(1.2* 10⁹) = 73.5 L
Calculation#4 Apparent Attenuation= OG-FG/OG
18.2-3.96/18.2 = 78.24%

3. Section#2 Bill of Materials
Bill of Materials
Water Treatments
Name Amount
CalciumChloride
11.00 g @ 3:05
PM
Grist Bill- MashInTime 3:06 PM
Name Amount (kg) Type % of GristBill
Pale Malt 2-row 14.00 Malt 84.59%
RoastedBarley 0.83 Adjunct 5.02%
BrewersMalt 0.60 Malt 3.63%
Chocolate Malt 0.42 Malt 2.54%
Dark Chocolate 0.13 Malt 0.79%
FawcettDark Crystal 0.57 Malt 3.44%
Total 16.55 100.00%
Hops
Name Amount (g) IBUs AA%
Target
26.8 g @ 4:20
PM 11.30 11.00%
Yeast - Pitched@ 5:47 PM
Name Amount (L)
Fat Tire .68 L
Other Materials
Name Amount Type Step In Process
RaspberrySyrup 60 grams Flavor SecondaryFermentation
Cocoa Nibs 450 grams
Kettle
Adjunct AfterKnockout@ 5:46
Whirlfloc 1 Tablet@ 5:10 Fining Boil

4. Section#3 Procedure
Pre Mash-in/Mash-in3:06 PM
Sanitation of the Chill Wizard
Before the mashinprocess,waterwas addedtoboth the hot liquortank. The cleaningcycle forthe Hot
LiquorTank and the ChillWizard plate heatExchangerwascompleted.Thiswasachievedby heating
waterto the strike temperature of 75°C.The hot liquoristhencirculated throughthe PHEuntil the
waterruns clearto eliminateanycontaminantsinthe line.
The studentsmashedinat 3:06 PM at a temperature andpH of 68°C and 5.45, respectively.The mash-in
technique wassingle infusionisothermal mash A single infusionmashimpliesmashinginandwort
separationoccurin the same vessel.Anisothermal mashoccurswhenthe brewerholdsthe mashat
single temperature forthe durationtoaccomplishsaccharification,proteinsolubilization,ect..The
maltedbarleypreviouslyweighedand milledbyatworoll hand crank mill were addedtothe mashtun
of the SABCOsystem. Figure 1describesthe SABCOBrewMagicSystemandidentifieskeyfeaturesthat
allowforease of process.
Figure 1. SABCOBrewMagicSystem
The brewsystemconsistsof three vessels.The mashtunacts as both a wort extractionandwort
separationvessel.Inthe bottomof the mashkettle isa false bottomtoholdthe grain bedforwort

5. separation.Onthe right,the hot liquortankismeantto holdsparge water,sanitationtopumpthrough
the systemandso on. The boil kettle onthe leftisa vessel meanttoholdwortwhenit hasbeen
separatedfromthe spentgrain.All three vesselsare heatedviadirectflamefromgasfuel.Gasis
directedbya pipe andvalve system.Liquidsare circulatedalsobyapipe andvalve systemseparate from
gas loop.To encourage flowandcirculation,the SABCOreliesonapumplocatedonthe rightside of the
system.The pump,alongwiththe temperature sensorsare monitoredandcontrolledbyaProgram
Logic Controller(PLC) locatedinside the counsel.Studentscankeeptrackand control systemthrough
interactionwiththe monitorinthe frontof the counsel.
Holdingthe mashat thistemperature favorsβ- amylase activity.β- amylaseisahydrolyticenzyme with
a primaryfunctionof creatingmaltose frommodifiedbarleystarch(amylose and amylopectin)
beginningfromthe non-reducingendsatan optimumtemperatureandmashpH of 64°C and 5.5;
respectively.Itfunctionsbyhydrolyzingevery2ndα-1,4glycosidicbondfromthe non-reducingendsof
amylose andamylopectin.β- amylase cannothydrolyze α-1,6bondsthatamylopectin(α-1,41,6 D-
glucopyranose).Since barleymaltusuallyconsistsof 25% amylose (α-1,4D-glucopyranose) and75%
amylopectin,the mashtemperature andpHalsoneedstobe in the optimumrange forthe enzyme α-
amylase (64-75, 5.2). The α-amylase enzyme isahydrolyticenzymethatworksbyhydrolyzingα-1,4
glycosidicbondsinarandom fashion.The endresultopensupthe restof the starch granule forβ-
amylase tohydrolyze bycreatingnewnonreducingendsaswell asa limitedamountof fermentable
sugars (glucose,maltose,maltotriose).Together,the actionsof these twoenzymesaccomplishthe
processof saccharification.
Vourlauf- 3:26PM
The class initiatedthe vourlauf (orrecirculation) processtoredistributethe sugars throughthe
suspension.Thisalsoiscritical inclarifyingthe wortandreducesthe chance of stickingof the mash and
reducingextractyield.Thiswasachievedbyopeningthe mashtopumpvalve (valve 4) andthe pumpto
mash valve (valve 5);producinga circulationloop.
Runoff- 3:36 PM
The lauteringprocess(spargingandrunoff) beganwiththe initial runoff.Runoff wasachievedby
filteringthe extractthroughthe maltandadjuncthusk,throughthe false bottom,andto the boil kettle
(throughvalve 2).The brewkettle wasfilledfromthe topwhichmayincrease oxygenatingthe wort.
Oxygenationof the wortcancause flavorvolatilizationandshelf stabilityissues.
Sparge- 3:48 PM
The spargingprocessconsistedof openingvalve2to beginrunoff.Then,approximately22.6litersof hot
liquor(at80°C) was circulated tothe mashtun throughvalve 3 (hotliquortomash tun) locatedonthe
rightside of the mashtun.The mashwas not agitatedduringthe wortseparationprocess. Thismay
have had a negative effectonfermentable sugarextractionandflow rate.The purpose of the sparging
the mash isto increase extractyieldbyusingthe hotsparge wateras an extractingagent.The waterfalls
throughthe spacesin betweenthe nearlyspentgrainsanddissolvesanyremainingsugarsintosolution.
The rest of the extractwasrunoff and the boil wasinitiated. Sparge andrunoff endedat4:20 PM.

6. Boil/ Boil Hop Addition- 4:20 PM
Pre-boil volume was 49 liters. The boil wasinitiatedat4:20 PM
The boil kettle wasa directflame systemburningpropanegaswithnoexhaustcollectionsystem. Direct
fire boilingcanhave a negative effectsonheatingvessels.Directflamecontactwiththe bottomof the
vessel cancause foulingof heatingsurfaces.Foulingoccurswhenwortmaterialsare essentially“baked”
ontothe sidesof the heatingvessel.Thesematerialshave theirownheatcoefficientthatthermal
energyhasto pass throughto heatthe wort alongwiththe heatcoefficientof the stainlesssteel.Over
time,foulingcanreduce the efficiencyof the boilerandthe overall brew.Directfire boilscancause heat
stresscrackingof the equipmentaswell if heatisappliedtooquicklyandattoo highof an initial
temperature.
Target hoppelletswere addedatthe beginningof the boil.Targetbecame one of the more popularhop
varietiesinEnglandafteritsreleasein1972. Eventhoughitis regardedasa highalphaacid hop, ithas
poor shelf life.The figure below showsthe total lupulinglandprofile.
Figure.TargetLupulinGlandProfile
Consistentboilinghelpsinthe extractionandisomerizationreactionsof alphaacidshumulone,
cohumulone,andadhumulone.Inthisreaction,the alphaacidsare heated.Iso-alphaacidsare
exceedinglymore soluble inwaterincomparisontoalphaacids. Thissolubilizationbetterstabilizesthe
wort microbially.The figure belowshowsthe reactionoverheat.
Figure.
Anotherobjectiveof the hopboil istoformulate trub.The increase intemperature initiatesthe
interactioninbetweenproteinsandpolyphenols.Theybothdissociateandcome outof solution.Metal
divalentcationsalsodissociate outof solutiondue tothe temperature increase andthe pHreduction.
Colorcompoundsare alsocreatedthroughMaillardreactionsinducedbywortboiling.Theses
compounds(caramelsandmellanoidins) are createdwhenheatisappliedtoreducingsugarsand
alpha acid % 9.5-12.5 total oil % 1.2-1.4
beta acid % 4.3-5.7 cohumulone % 35-40
myrcene % 45-55 % farnesene % <1%
humulene % 17-22 caryophyllene % 8.0-10.0

7. compoundswithanaminogroup (usuallyproteins).Thiscreatesabrowningeffectinafoodproduct or,
inthiscase, a wort solution.
WhirlflocAddition- 5:10 PM
The whirlflocwasaddedtothe boiledworttoinduce the hotbreak (trub). The Whirlflocconstitutesof a
blendof Irishmossand carrageenan;bothknowntobe kettle finingstoaidintrub formation.Whirlfloc
isformedof negativelychargedparticlesthatprecipitatehighmolecularweightproteinoutof solution.
Thishelpsclarifythe boiledwort.
Flameout/Whirlpool- 5:20PM
The heatingof the wortconcludedwith the lasthopedition.A secondspecificgravitymeasurementwas
takento determine the original gravityThe boiledwortwasbroughtintoastate of whirlpool.The
Whirlflocaddedpreviouslytothe solutionaidedasa catalystto the protein/polyphenol interaction,
causingthe trub constituentstoflocnearthe top of the wort.The mainpurpose of the whirlpoolisto
pull formedtrub,usingcentripetalforce,tothe middle of the kettletosettle andbe collectedatthe
bottomof the tank.Otherequipmentthatcouldbe usedforthisprocesswouldbe a whirlpool tank,a
wort settlingtank,ahopback, or a decantercentrifuge.Thisclarificationprocessisalsowhere syrups
(alsoknownaskettle adjuncts) mightbe addedtomanipulate concentration.
Start Knockout/ Heat Exchange- 5:32 PM
The hot break(containinghighmolecularweightprotein/polyphenol complexes,hopdebris,divalent
cations,some lipidmaterial) iseithercroppedoff orcollectedinthe initial stagesof wortcoolingbefore
the chiller.If the material isnotremoved:proteinmaybe lefttosolubilize backintosolution(causes
filtrationissueslateron),polyphenolsmaycome backintosolution(undesirable dryingcharacteristics
and can alsocause chill haze),metal divalentcationsmaycause shelf stabilityissuesthroughoxidation,
and lipidmaterial maycause unevenfermentation.Atequinox,the trubwascollectedinthe beginning
fromthe bottom.Once the trub wascollected,boiledwortwastransferredthroughaplate heat
exchangerand injectedwithoxygen toreduce the temperature to15°C and to oxygenate the wort.
Reducingthe temperature allowsoxygentobe more soluble intothe wortsolutionandprovidesthe
yeastan environment suitable toperformprocesses suchasglycolysis,proteindigestion,and
fermentation.Itisnecessarytooxygenate the wort,especiallyatthe beginningof fermentation,for
yeastto synthesizesterolsandunsaturatedfattyacidsproducedduringthe aerobicphase of
fermentation. These lipidswillbe usedto create cellularmembranesfornew yeastcells(growthphase).
The figure belowisanimage of the ChillWizardplate heatexchangerusedtoreduce the wort
temperature.
Figure ChillWizardPHE

8. End Knockout/ YeastPitch 5:46 PM
A brewercancontrol manyaspectsof sensoryperceptionjustbymanipulatingthe yeastpitchrate.By
increasingthe pitchrate,yeastgrowthwill decrease because of competitionfornutrients.The
productionof isoamyl acetate andhigheralcoholswill decrease aswell asfermentationtime.However
ethyl acetate productionwillincrease.Bydecreasingthe pitchrate,yeastgrowthwill increase byvirtue
of more lesscompetitionfornutrients.Flavorssuchasestersandisoamyl acetate will increase.Hop
aroma and fermentationtime will alsoincrease.
Duringfermentation,yeastundergofourphases:lagphase,growthphase,fermentation,and
flocculation.Inthe lagphase of fermentation,yeastconsumeoxygengivenfromoxygenatedwortto
produce lipidsnecessaryforcellularmembrane productionfornew yeastcells.Yeastalsosynthesize
enzymessuchas(blank) tosupportgrowth. Afterthe lag phase,the yeaststartthe growthphase.Cells
start to budand create daughtercells.The populationincreaseslogarithmicallyandincreasesvessel
temperature.Fermentationbeginswhenyeaststartto metabolizethe sugarspresentinthe wort.
COP
Afterthe worthad beentransferredfromthe mashtunto the brew kettle,the mashtunwas detached
fromthe SABCOsystemtobe cleaned.The spentgrainswere removedfromthe mashtunand
transferredtoa bucketto be usedfor animal feed.The mashtunwastakenapart and rinsed.Itwas then
returnedandattachedto the SABCOsystemforCIP.
Once the boiledwortwastransferredtothe fermenter,the boil kettle wasdetachedfromthe heat
exchangerandrinsedout.Rinsedouthopsedimentswere addedtothe animal feedbucket.Whenthe
rinse wascomplete,the brewkettlewasalsoreturnedandattachedtothe SABCOsystem.
CIP
The CIP systemonthe SABCObrewingsystembeganwithfillingthe liquortankwitha cleaningsolution
valves3 and 5 were openedtoallowforfull circulationthroughthe liquidline.The pumpwasturnedon
alsoto allowforcirculation. Asthe liquortankwas depletedof itscleaningsolution,the tankwasrinse d
out withhose water.Valve three isthenclosedandcleaningsolutionisfocusedonthe mashtun and
boil kettle partof the system.Valve 4and the drainin the SABCObox are openedtocirculate the
cleaningsolutionthroughthe mashtun.Then, the idophorsanitizeriscirculatedthroughthe mashtun,

9. throughthe heat exchanger,intothe SABCOpumpandbackto the mashtun. The mash tunis emptied
intoa collectionbuckettoremove sanitizer.The remainingsolutionisrinsedoutwithwatertoremove
residual sanitizer.
Primary Fermentation11/6/15 – 12/3/15
Duringthe primaryfermentationyeastbegantometabolizethe wort.There are three mainobjectivesto
fermenting.Toharvestethanol,CO₂,andflavorcomponentsexcretedbyyeastduringglycolysis. Yeast
usuallyfavorrespirationoverfermentation,however,due tocarboncatabolite suppression,yeastwill
favorfermentation. Certainnutrientsare necessaryforyeastto ferment.Primarynutrientrequirements
include anitrogensource anda carbon source (providedbymaltedbarley,gelatinizedadjuncts).Yeast
alsorequiresmolecularoxygenforlipidproduction(creationof cellularmembranes).Mineralssuchas
Zincand Magnesiumact as cofactors forenzymesinthe fermentationcycle (alcohol dehydrogenaseand
pyruvate decarboxylase)andare alsorequiredforhealthyyeastfermentation.
Fermentable Sugar Uptake by Yeast Cells
To beginfermentation,sugarscreatedinthe mashingstepmustbe takenintothe cell.The following
figure showsthe uptake of sugarintothe yeastcell.The figure below showsthe breakdownanduptake.
Three sugar transportenzymesallowforfermentable sugarstopassthroughthe cell envelope:glucose
permease,maltosepermease,andputativemaltotriosepermease.Sucrose invertase iscovalently
attachedto the cell wall. The sucrose invertase breaksthe glycosidicbondinbetweenfructose and
glucose tocreate separate molecules.These glucoseandfructose moleculesare thentakenintothe
yeastcell byglucose permease. Intracellularmaltase breaksdownglycosidicbondsinbetweenmaltose
and maltotriose sothe sugarsmaybe used forglycolysis.
Glycolysis
A keycomponentof fermentationisthe yeast’sabilitytoconvertglucose andfructose intoenergyand,
subsequently,ethanol andCO₂asbi-products.The figure below providesasimple representationof the
Embden-Meyerhof-Parnaspathwayof glucose metabolism.
Figure.SimplifiedRepresentationof Glycolysis

10. The processbeginswithglucose beingphosphorylatedbyATPbythe enzyme hexokinasetoyielda
glucose 6-phosphate.Thisisisomerizedbyphosphoglucose isomeraseintofructose 6-phosphate.This
compoundisphosphorylatedagaintoyieldfructose 1,6biphosphate byphosphofructokinase.This
compoundishydrolyzedbythe enzyme adolase togive two,three carbonphosphates (glyceraldehyde
3-phosphate and3-phosphoglycerone).Triosephosphate isomerase isomerizesthe latter(reaction
favors3-phosphoglycerone) toglyceraldehyde 3-phosphate.Thisisoxidizedinareactionthatis
mediatedbyadehydrogenase andaNAD⁺as a cofactor.The endresultis1,3 biphosphoglycerate.The
hydrolysisof the phosphoesterlinkageatthe 1st
carbon of thisproductreleasesalarge amountof
energy(viaphosphoglycerokinase).Thisenergyisusedtosynthesize ATP.Since twomoleculesof
glyceraldehyde 3-phosphateare metabolizedforeachglucose molecule enteringthe pathway,the two
ATP consumedinthe processare restored.Lastly,the enzyme phosphoglyceromutase converts3-
phosphoglycerate to2-phosphoglycerate.The removal of waterbyenolaseyieldsphosphoenol
pyruvate.
Pryruvate iscarbon isremovedinthe formof CO₂ by the enzyme pyruvate decarboxylase yielding
ethanol.Hydrogenisthenremovedbythe enzymealcohol dehydrogenase withNAD⁺asa cofactor
yieldingethanol.The figure belowshowsthe conversionof pryruvate toethanol.
Figure

11. Yeasttendto flocculate whenthe targetalcohol contenthasbeenachieved.The brewerappliesfreezing
temperaturestothe fermenterto“coldcrash” the yeast.Yeastisthencollectedoutof the cone.The
figure belowshowsthe fermenter.Thisprocessoccursbefore conditioning.
Figure.GiffordVCF
Conditioning
A total of 2.3 volumesof CO₂were addedtothe Imperial Stout.The TA’sdidthisbyaddinga corn syrup
and watersolutiontothe beer.218.58 grams of corn syrupwas usedtoachieve the correctamount of
carbonation. The three purposesof maturationisflavormaturation(VDKreductionandacetylaldehyde
reduction),carbonation,andclarification.
Viscinal diketoneandacetyl aldehyde formationoccurnaturallyinmaturation. Diacetyl occursnaturally
inbay oil and butterandis usedas a flavoranttoconveybutterypropertiesinpopcornandmargarines
etc.Diacetyl isalsoa productof nitrogenmetabolism.Asacarbonyl compounditis formedfroma-
acetolactate whichisinvolvedinaminoacidproduction.Itislatterdecarboxylatedandreducedto
acetoinand2,3-butanediol.Essentiallythe keyintermediate productof mainstreammetabolism
(pyruvate) isconvertedtoa-acetolactatewhichfeedsvaline andothermetaboliteformation.Anyexcess
a-acetolactate issecretedfromthe yeastcell whereitcanthenbe spontaneouslydecarboxylatedinto
diacetyl.Yeastcellsreabsorbthe diacetyl (undersuitable conditions) wherebyitcanbe metabolizedinto
acetoinandbutanedione. The figurebelow describesthe formationof diacetylandthe conversionof
the diacetyl to2,3 butane diol.

12. Clarificationincludesthe settlingof yeastandchill haze.Chillhaze iscausedbyacidicproteins
interactingwithpolyphenolsviahydrogenbonding.These compoundsoxidize and polymerize tocreate
tannoids.Tannoidsthemselvescanfurtherpolymerize andformcovalentbondswithothertannoids,
producingchill haze.
Section#4 Complete BJCP SensoryEvalutaiton
Beer Style- Imperial Stout
Aroma- 10/12 Initial aromaverymaltyto roastednotes.FruityEsterssubtle,notpronounced.A little
prunyon the end.
BJCP- Rich and complex,withvariable amounts of roasted grains, maltiness,fruityesters,hops,and
alcohol.The roasted malt character can take on coffee,dark chocolate,or slightlyburnt tonesand can
be lightto moderatelystrong. The malt aroma can be subtle to rich and barleywine-like,dependingon
the gravity and grain bill.May optionallyshow a slightspecialtymalt character (e.g.,caramel),but this
shouldonly add complexityand not dominate.Fruity estersmay be low to moderatelystrong, and
may take on a complex,dark fruit(e.g.,plums,prunes, raisins) character. Hop aroma can be very low
to quite aggressive,and may contain any hop variety. An alcohol character may be present,but
shouldn’tbe sharp, hot or solventy.Aged versionsmay have a slight vinousor port-like quality,but
shouldn’tbe sour. No diacetyl.The balance can vary with any of the aroma elementstakingcenter
stage. Not all possible aromas describedneedbe present;many interpretationsare possible.Aging
affectsthe intensity,balance and smoothnessof aromatics.
Appearance 3/3
BJCP- Color may range from verydark reddish-brownto jetblack. Opaque. Deeptan to dark brown
head. Generallyhasa well-formedhead,althoughhead retentionmay be low to moderate. High
alcohol and viscositymay be visible in“legs” whenbeerisswirledin a glass.
Actual- Headhas a reddishbrowntint. Low headretention.Colorof bodyis darkbrownto mahogany.

13. Flavor 15/20
BJCP- Flavor: Rich, deep,complexand frequentlyquite intense,withvariable amounts of roasted
malt/grains, maltiness,fruityesters,hop bitternessand flavor, and alcohol.Mediumto aggressively
high bitterness.Medium-lowtohighhop flavor (any variety).Moderate to aggressivelyhighroasted
malt/grain flavors can suggestbittersweetor unsweetenedchocolate,cocoa,and/or strong coffee.A
slightlyburnt grain, burnt currant or tarry character may be evident.Fruityestersmay be low to
intense,andcan take on a dark fruit character (raisins,plums,or prunes).Malt backbone can be
balanced and supportive to rich and barleywinelike,andmay optionallyshow some supporting
caramel, bready or toasty flavors.Alcohol strength shouldbe evident,butnot hot,sharp, or solventy.
No diacetyl.The palate and finishcan vary from relativelydry to moderatelysweet,usuallywith some
lingeringroastiness,hopbitternessand warming character. The balance and intensityofflavors can
be affectedbyaging, with some flavors becomingmore subduedovertime and some aged,vinousor
port-like qualitiesdeveloping
Actual- Intial raspberryflavorpresent,maymix withfruityesters.Some lingeringbitterness.Alcohol
notesapparent.Cocoanibsgive sweeteraftertaste andcombine withsomeof the maltnotesfromthe
gristbill.
Mouthfeel- 4/5
BJCP- Full to very full-bodiedandchewy,witha velvety,luscioustexture (althoughthe body may
decline withlong conditioning).Gentle smoothwarmthfrom alcohol shouldbe presentand
noticeable.Shouldnot be syrupy and underattenuated.Carbonationmay be low to moderate,
dependingonage and conditioning.
Actual- Warmth fromalcohol present.Mediumbody.A little bitof creaminess.Adequate carbonation.
Overall Impression-8/10
BJCP- An intenselyflavored,big,dark ale.Roasty, fruity, and bittersweet,witha noticeable alcohol
presence.Dark fruit flavors meldwith roasty, burnt, or almost tar-like sensations.Like a black
barleywine witheverydimensionofflavor coming into play.
Actual- The dark ale leavesnothingtobe desired;bringingcomplexityin flavor,aroma,andappearance.
Mouthfeel wasexceedinglypleasant.
Total- 40/50
Section#5 Results and Discussion
The beerwas verymediuminbody.Thiswassurprisingfromanimperial stoutthatusuallyhasa
commandinglyfullbody.Thisfactcouldsuggestthe lackof higheralcohols(e.g.glycerol) wasnot
producedduringfermentation.Thisobservance couldalsosuggest thatadequate attenuationwas
achieved,since asyrup-like viscositywouldbe yieldedfromunderattenuation.

14. The sensoryevaluationobservedfruityestersfromthe aromaand the flavor.These flavorswere
enhancedand/orwere complementedbythe blackraspberrysyrupaddedduringsecondary
fermentation.The esterformationcouldhave beendue tothe
References:
1. http://www.alcbevtesting.com/wp-content/uploads/2009/05/DiacetylNewsWORKCopy.pdf