Degree of Roast.docx

Degree of Roast.docx

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DegreeofRoast

DegreeofRoast,Temperature,Description

ThiscoffeewasroastedonmyProbat12kilosoIcouldtakeadvantageofthesampletrier. Ignorethetimes,andtakethetemperaturesasaballparkfigure.

Theimportantthingishereistoseethetransformationthecoffeegoesthroughasitroastsandwhatlook, color, beansize and surface texture, correspondstothedegreeofroast.***（seenotefromhomeroasterGeorgeSteinertbelow）.

Roastingismoreaboutexceptionsthanrules.Ihave thispage aboutbeancolorvs.groundcoffeecolorthatmightbehelpful.Sogettoit.

（clickonpreviewforfullsizeimage）

Note:

Theaboveimageisnottheexactsamebeanspicturedbelow.Thegraystripsoneithersideofthisimageareaphotographic18%graycard.

1.Greenunroastedcoffee0:

00-75f

Thisisawetprocessed,CentralAmericancoffee,aaccidentalblendIhavehadsittingaround.EachphotoherearedifferentcoffeeseedsfromthebatchIroastedso sizeandshapewillvary seedtoseed.

Clickonimageforlargephoto,or here formulti-beanphoto

2.Startingtopale 4:

00-270f

Drumroasterstakealongtimetotransferheattocoffeesothereislittlechangeinthefirstfewminutes.Inanairroastercoffeegetstothisstagesomuchfasterbecauseoftheefficientheattransferenceoftherapidmovingairstream,sothewholewarm-upphasecanbeasfastastwominutes.

Oddlookingseeds-thenearonemightbeaKonaTypicaandthefartheroneperhapsthetraditionalBourboncultivarorMundoNovo. Clickonimageforlargephoto,or here formulti-beanphoto

3.Earlyyellowstage 6:

00-327f

Atthispointthecoffeeisstilllosingwaterintheformofsteamandnophysicalexpansionofthebeanhastakenplace.Thecoffeehasaveryhumid,hay-likesmellatthispoint.Allofthesewarm-upstagesleadinguptofirstcrackarepartofanendothermicprocess,asthecoffeetakesonheat,leadingtothefirstaudibleroastreaction,theexothermic1stcrack.

Clickonimageforlargephoto,or here formulti-beanphoto

4.Yellow-Tanstage 6:

30-345f

Theroastisstartingtoassumeabrownercolor,andamarblingappearanceisstartingtoemerge.Nobeanexpansionyet.Thefirst"toasty"smells（toastedgrain,bread）canbedetected,andabitlesswet,humidaircomingoffthecoffee.Notethatsomecoffeesturnabrighterandmoredistinctyellowatthistime,suchasCostaRicanandMexicancoffees.

Clickonimageforlargephoto,or here formulti-beanphoto

5.LightBrownstage 8:

00-370f

Firstcrackisdrawingnearatthispoint.Somebeanexpansionisvisibleasthecentralcrackinthecoffeehasopenedslightly.Thecoffeereleasessomesilverskinorchaff.

Clickonimageforlargephoto,or here formulti-beanphoto

6.BrownStage 9:

00-393f

Nowwearerightatthedooroffirstcrack.Thecoffeehasbrownedconsiderably,whichispartlyduetobrowningreactionsfromsugars,butlargelyduetoanotherbrowningreactioncalledtheMaillardReaction（whichalsoisresponsibleforbrowningofcookedbeef!

）

Clickonimageforlargephoto,or here formulti-beanphoto

7.1stcrackbegins 9:

20-401f

Atthispoint,theveryfirstpoppingsoundsoftheFirstCrackcanbeheard.Thissoundcanbesimilartopopcornpops（indistinctiontothesoundoftheSecondCrack,whichhasashallowersound,morelikeasnap）.Atthepointoffirstcracktheinternalbeantemperaturewouldbearound356f.

Clickonimageforlargephoto,or here formulti-beanphoto

8.1stcrackunderway 10:

00-415f

Asfirstcrackcontinuesthecoffeestillappearsmottledandunevenincolor.Thecoffeestartsexpandinginsizeandshowsvisiblecracks.Theamountofchaffinthecreaseoftheseedisnoticeablyless.

Firstcrackisanexothermicreaction;thebeansaregivingoffheat.Butthenthebeansquicklybecomeendothermic,meaningthataroasterthatisnotaddingenoughheattotheprocesswillstalltheroastatthispoint...notagoodthing.Oncecaramelizationbegins（340-400degreesinternalbeantemperature）aroastthatloosesheatwilltaste"baked",perhapsduetothedisruptiononlong-chainpolymerization.Themeltingpointofsucroseis370fandcorrespondstothiswindowoftemperatureswhencaramelizationbegins.

Clickonimageforlargephoto,or here formulti-beanphoto

9.1stcrackfinishes 10:

40-426f

Thisisconsidereda CityRoast.Firstcrackisdoneandtheroastisstopped.

Noticethebeansurfaceissmoothersomewhatfromexpansionbutstillhasdarkermarksinthecoffee,likeafinelyetchedpattern.Theedgesoftheseedarestillfairlyhard.Atthispointthecoffeestartsgivingoffcarbondioxide.

Clickonimageforlargephoto,or here formulti-beanphoto

10. City+roast 11:

05435f

City+meansthecoffeehasclearedfirstcrack,andtimeisallowedforanevenbeansurfaceappearancetodevelop.

Thereareonlyverysmallchangesbetweenthe#9pictureaboveandthisone,notablytheedgesofthebeanareabitsofter.Thewholestagebetweenthefirstandsecondcrackisashortperiod（15to30seconds）wherealotishappeningchemicallytothebeans.Thecoffeegainsheatonceagainuntilitswoodycellulosematrix,thebeanstructureitself,beginstofracture...thatis,theSecondCrack.

Clickonimageforlargephoto,or here formulti-beanphoto.Checkhereforthe wholebeanvs.groundcoffeecomparisonphotos ora MacrophotosofasingleCity+bean.

11. FullCityroast 11:

30-444f

Onthevergeof2ndcrack

ThisimagerepresentsaFullCityroast;thecoffeeisonthevergeof2ndcrack.Thismightbehardtojudgethefirstfewtimesyouroast;afterawhile,youwillhaveafeelforit.Thebeansarehaveaslightsheenofoilandtheedgesaresofter.

Theinternalbeantemperatureforsecondcracknormallyis446degreesfarenheit.Butinfactsecondcrackisabitlesspredictablethanfirstcrack,inmyexperience.Why?

ItcouldbeduetothefactthatfirstcrackisthephysicalexpansionofthecoffeeseedaswaterandcarbondioxidesplitandCO2outgassingstarts.SecondCrackisthephysicalfracturingofthecelllosematrixofthecoffee.Thismatrixisbothorganizedcellulosethatreactsreadilytoheat,andnot-so-organizedcellulosethatdoesnot.Sinceeverycoffeeisphysicallydifferentinsizeanddensityduetothecultivar,origin,altitude,etc.,itmakesensethattheparticularcellmatrixisdifferenttoo,andnotasuniversallyconsistent.

Clickonimageforlargephoto,or here formulti-beanphoto Checkhereforthe wholebeanvs.groundcoffeecomparisonphotos ora MacrophotoofasingleFullCitybean

12. FullCity+roast 11:

50-454f

Firstaudiblesnapsof2ndcrack

ThedarkersideofaFullCityroastisFullCity+,wherethecoffeehasbarelyentered2ndcrack.Afewsnapsareheard,andtheroastisthenstopped.Secondcrackmaycontinueintothecoolingphase-thisiscalled"coasting".Themoreeffectiveandrapidyourcooling-thebetteryourabilitytostoptheroastatthedegreeyouwant.

ComparethefullsizeimagesfromtheFullCityroastandthisone,andIthinkitiseasytoseeadifference.Well,maybenoteasy,buttheFullCity+roastisabitfuller,moresmallcracksontheface（orflatside）ofthebean.

Clickonimageforlargephoto,or here formulti-beanphotoor 

aMacrophotoofasingleFullCity+bean

13. Vienna-LightFrenchroast12:

15-465f

2ndcrack isunderway

（Thisismy darkest espressoroast）

TheViennastage（alsocalledContinental）toLightFrenchstageiswhereyoubegintofind OriginCharacter eclipsedby RoastCharacter.Adarkorheavyroastisatoddswithbuyingcoffeeforitsdistinctoriginqualities.Darkroastcoffeestendtotastemorelikeeachother-asthedifferencesduetodistinctoriginsareobscuredbythecarbonyroastflavors.Nontheless,somecoffeesareexcellentatthisstage（ourPuroScuroblendisengineeredforthisroastrange）.

Bytheway;Espressoisnotaroast.ButNorthernItalianstyleespressoisusuallyroastedto440-446internalbeantemperature.SouthernItalian（Scura）isgenerallyaLightFrenchRoastorataddarker.

Clickonimageforlargephoto,or here formulti-beanphoto. Checkhereforthe wholebeanvs.groundcoffeecomparisonphotos ora macrophotoofasingleFrenchroastbean.

14. FullFrenchroast 12:

40-474f

2ndcrack isveryrapid,nearingitsend.

Sugarsareheavilycaramelized（readasburned）andaredegraded;thewoodybeanstructureiscarbonizingandtheseedcontinuestoexpandandloosemass.Thebodyoftheresultingcupwillbethinner/lighterasthearomaticcompounds,oils,andsolublesolidsarebeingburnedoutofthecoffeeandrisinguptofillyourhousewithsmoke.474iswellbeyondanyroastIdoontheProbat.Iwillgoashighas465onacoupleblends,andthat'smylimit.

Noticehowfastanddramaticthechangeisfromthepreviousphoto-allthathappenedinlessthan30seconds!

Clickonimageforlargephoto,or here formulti-beanphoto

15.Fullycarbonized 13:

00-486f

SomecallthisItalianorSpanishroast,aninsulttoeither!

Atthisstage,thecoffeecanbeover25%ash;itiscarbonized,dead,charcoal.

Clickonimageforlargephoto,or here formulti-beanphoto

16.Imminentfire... 13:

30-497f

Thisbeanisrightatthevergeoffire-infactyoucanactuallystartafirewithalargebatchonceyoudumpthecoffeeoutoftheroastdrumintothecooltray.Thesuddenrushofoxygenmightbetheneededingredientfor cafedelfuego.Kids,grabyourmarshmallows!

 Hopeyoulike'emsmokey!

Needlesstosay,thisroastlevelisfull-oncarbonandyoucanwriteyournamewithacoffe