Research Library Research Library

Bulletins 4000 - Research Publications

8-2013

Effect of smoke in grape and wine production Effect of smoke in grape and wine production

Kristen Brodison

Follow this and additional works at: https://researchlibrary.agric.wa.gov.au/bulletins

Part of the Viticulture and Oenology Commons

Recommended Citation Recommended Citation Brodison, K. (2013), Effect of smoke in grape and wine production. Department of Primary Industries and

Regional Development, Western Australia, Perth. Bulletin 4847.

This bulletin is brought to you for free and open access by the Research Publications at Research Library. It has been accepted for inclusion in Bulletins 4000 - by an authorized administrator of Research Library. For more information, please contact library@dpird.wa.gov.au.

Bulletin 4847ISSN 1833-7236

Department ofAgriculture and Food

Effect of smoke in grape and wine production

Supporting your success

2

AcknowledgementsWe acknowledge the assistance and contributions of:

• GlynnWard,DianaFisher,RichardFennessy, AndrewTaylor,PeterGardiner,ArtDiggleand RosalieMcCauleyfromDAFWA

• MichaelRentonandMichaelAireyfromTheUniversity of Western Australia

• JohnWhitingfromtheDepartmentofPrimaryIndustries,Victoria

• CoryLouisfromAdvancedTechnologyProducts.

ThepublicationofthismaterialwassupportedbytheGrapeandWineResearchandDevelopmentCorporation(GWRDCProjectDAW0901).

DisclaimerTheChiefExecutiveOfficeroftheDepartmentofAgricultureandFoodandtheStateofWesternAustraliaaccept no liability whatsoever by reason of negligence orotherwisearisingfromtheuseorreleaseofthisinformationoranypartofit.Recommendationswerecurrentatthetimeofpreparationofthismaterial(2013).Inrelyingonorusingthisdocumentoranyadviceorinformationexpresslyorimpliedlycontainedwithinit,youacceptallrisksandresponsibilityforloss,injury,damages,costsandotherconsequencesofanykindwhatsoever resulting directly or indirectly to you or any otherpersonfromyourdoingso.Itisforyoutoobtainyour own advice and conduct your own investigations andassessmentsofanyproposalsthatyoumaybeconsideringinlightofyourowncircumstances.

©WesternAustraliaAgricultureAuthority2013

For copyright enquiries please contact the Department of Agriculture and Food, Western Australia.

Copiesofthisdocumentareavailableinalternativeformatsuponrequest.

3Baron-HayCourt,SouthPerthWA6151

Tel:+61(0)893683333Email:enquiries@agric.wa.gov.auWebsite: agric.wa.gov.au

Sources of further informationFurtherinformationontheeffectsofsmokeongrapeand wine production and current research can be obtainedfromtheGrapeandWineResearchandDevelopmentCorporation(GWRDC)at gwrdc.com.auandtheAustralianWineResearchInstitute(AWRI)atawri.com.au

3

Effect of smoke in grape and wine productionKristen Brodison (nee Kennison), Viticulture Research and Development Officer

Bulletin 4847August 2013

ISSN 1833-7236

4

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Seasonal sensitivity to smoke uptake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Effectofsmokeonvarieties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Implicationsofsmokedensityandduration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Potentialcarry-overofsmoke. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Effectonwineproduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Smoke effect reduction system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

SmokeTaintRiskcalculator(STAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Vineyardlocationmapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Timingofkeygrowthstages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Calculationofsmokeriskfactors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Smokedetectioninthefield(nephelometers). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

In case of a smoke event in the vineyard … . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Ifasmokeeventisimminent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Ifasmokeeventhasoccurred . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

5

IntroductionSmokeexposureofgrapevinesandthedevelopmentofsmoke-relatedcharacteristicsintheresultingwinesisanincreasingissueforthewineindustry.AsAustraliafacesawarmingclimatewithmorebushfires,smokeexposureinvineyardsisbecomingmoreregular.

Winesmadefromgrapesexposedtosmokeduringsensitivegrowthstagescanexhibitaromasandflavoursresemblingsmokedmeat,disinfectant,leather,salamiandashtrays.Whereunfavourablesmokecharacteristicsaredetectedbyconsumersathighconcentrationsthewinemaybeunpalatable.Unsalablewinesresultinfinanciallossesforproducerswithcostsflowingontowinebrands,marketpresenceandfuturesales.

Fewtoolsandtechniquesarecurrentlyavailabletoremedytheproblemofsmokeeffectingrapesandwine,howeverasignificantadvancementhasbeenthedevelopmentoftheSmokeTaintRiskcalculator.Theriskcalculator(knownasSTAR)wasdevelopedbyresearchersattheDepartmentofAgricultureandFood,WesternAustralia(DAFWA)andTheUniversityofWesternAustralia(UWA)andpredictstheseasonalsensitivityofgrapevinestosmokeuptakeandsmokeflavourdevelopmentinwine.

UseoftheSTARcalculator,withotherpostharvesttechniquesprovidesopportunitytoeffectivelyreduceunwantedsmokeeffectsingrapesandwine.Thisbulletindetailskeyinformationonsmokeeffect,toolsandtechniquesforsmokereductioninvineyardsandwineriesandtheSTARcalculator.

6

BackgroundTheissueofsmokeeffectingrapeandwineproductionisrelativelyrecent.OneoftheearliestreportsresultedfromtheCanberrabushfiresof2003.ThesefirescosttheAlpineValleywineindustryanestimated$4millionandcausedsmokedamagetovineyardsinnorth-eastVictoriaandsouth-easternNewSouthWales.

TheAustralianWineResearchInstitute(AWRI)beganinvestigationsintothenatureandameliorationofsmokeeffectafterreceivingnumerousenquiriesfromproducersnoticingsmoke-relatedsensorycharactersinfruit,juiceandwine(Højetal.2003).

Sincethistime,furthersignificantfireshaveresultedinsmokedamagetowinegrapesandincluded:

• 2004,lossestovineyardsintheManjimupandPembertonregionsofsouth-westernWesternAustralia

• 2007,lossof15,000tonnesoffruitintheKingandAlpineValleys,Victoria

• 2009,theBlackSaturdayfiresinVictoriawereestimatedtocost$299millioninlostrevenue.

Consequently,researchinvestigatingsmokeeffectson grape and wine production has increased significantly.Thishasfocusedontheeffectofsmokeexposureonvinesandthesubsequentsmoke-relatedcharacteristicsingrapesandwine.Furtherresearchhasinvestigatedtheimpactofthesmoketiming,density,durationandassimilationbygrapevines.

7

Seasonal sensitivity to smoke uptake

Figure 1 Smokegenerationandapplicationapparatusincludingatentstructuretosurroundvines.

berries,beginningofbunchclosure,veraison,grapeswithintermediatesugar,berriesnotquiteripe,andharvest)tounderstandthelevelofsmokeeffectinthefinalwine(Kennisonetal.2011).Resultsshowedthethreekeyperiodsofvinesensitivitytosmokewere:

• Shoots 10 cm long to flowering: low sensitivity

• Pea-size berries through to three days post-veraison:variable(lowtomedium)sensitivity

• Seven days post-veraison to harvest: highly sensitive(seeFigure2).

To investigate when grapevines are sensitive and susceptibletosmokeuptake,apparatuswasdesignedandtestedtoapplysmoketofield-grownvines(Figure1).Thisconsistedofasteel-framedtenttosurroundvinestoapplysmokefromasmokedrum.WorkwasconductedonbothDAFWAandcommercialproperties.

ResearchwasconductedwithMerlotvinesoverthreeseasons,duringwhichtheywereexposedtosmokeatkeygrowthstages(10cmshoots,flowering,pea-size

8

Smokeexposurecanalsoresultindelayedripeningoffruit.Onsomeoccasions,studieshaveshownfruitfromsmoke-exposedvinestocontainlowersugarthanfruitfromunsmokedvines(Kennisonetal.2009).Thedelay in ripening is thought to be related to the effect of smokeonthefunctioningofthegrapevine,withfurtherstudies investigating the photosynthetic response of grapevinestosmokeexposure.

Effect of smoke on varietiesTheeffectsofsmokeuptakeinwinevarydependingonthevariety.PreviousstudiesfocusedonMerlotonly.Thesecomprehensivestudieswereconductedoverthreeyears.FurtherstudieshaveinvestigatedtheeffectofsmokeonothervarietiesincludingCabernetSauvignon,ChardonnayandSauvignonBlanc.Thesefoundthetimingofsmokeuptakevarieswithvariety.Forexample,somevarietiesmaybemoresensitivetosmokeuptakeearlierthanothers.

Thedifferencemaybeduetoanumberoffactorsincludingseasonalweatherconditionsandvinehealth.Wine grape varieties can differ in plant structure and inaspectssuchasberryskinthickness,whichmayaffectsmokeuptake.Winemakingtechniquescanalsoinfluencesmokecharacteristicsinthefinalwine.Generally,winefromwhitegrapevarietieshasfewersmoke-relatedsensoryandchemicaleffectsduetothereducedcontacttimeonskinscomparedwithredwineproduction.Allofthesefactorswereconsideredindevelopingthesmokeriskreductionmodel(STAR).

Implications of smoke density and durationExtensivefieldresearchwasconductedbyDAFWAtoestablishthequantityofsmokeexposureneededto

Figure 2 Keyperiodsofsensitivitytosmokeexposureanddevelopmentofsmoke-relatedaromasandcompoundsinwine,derivedfromthreeyearsofresearchofsmokeonfield-grownMerlotgrapevines.

Grapevine growth stagePotential

for smoke uptake

Shoots10cmlong

Low

Flowering Low

Pea-sizeberriesVariable(lowtomedium)

Beginning of bunch closure

Variable(lowtomedium)

Onsetofveraisonto three days post-veraison

Variable(lowtomedium)

Fromsevendayspost-veraison

to

Harvest

High

9

causeeffect.Thisusedfield-basedsmokedetectingequipment(nephelometry)tomeasurethedensityanddurationofsmokeappliedtograpevines.

Thedevicemeasuredsmokeinunitsofobscurationpermetre(%obs/m).Thisrelatestotheimpairmentofnormalvisionoveradistanceof1metre.AvisualdescriptionofsmokeobscurationpermetreandtheassociatedviewingdistanceisprovidedinFigure3.Smokewasappliedtovinesatvariousdensities(2.5,5,10,20and30%obs/m)anddurations(fiveto80minutes)duringgrowthperiodsdefinedassensitiveforsmokeuptake.

Theresultsshowedasingleheavysmokeexposure(30%obs/m)for30minutesatasensitivestageofgrowth(fromsevendaysafterveraisontoharvest)was

sufficienttocreatesmoke-relatedaromas,flavoursandcompoundsinwine(Kennisonetal.2008).Lowersmokedensities for shorter periods also applied at a sensitive vine growth stage can create differences detectablebyconsumers(Kennisonetal.2012).

Smoke-likearomasandflavoursarepronouncedinwinesproducedfromhighsmokedensities(20%obs/m)forshortdurations,andlowsmokedensities(2.5%obs/m)forlongdurations.Itisimportanttonotethatgrapeharvesting,handlingandwinemakingtechniquescaninfluencesmokeeffect.Techniquestoreducetheeffectsaredetailedfurtherinthisdocument.

The effect of repeatedsmokeapplicationstothesamevineswasalsoinvestigated.EightapplicationsweremadetothesameMerlotvinesthroughoutthe

Smoke obscuration

(%obs/m)

0.01

0.1

1

Viewing distance (m)

Figure 3Viewingdistance(inmetres)inrelationtothelevelofsmokeobscuration(%obs/masdeterminedbynephelometry).

10

growingseason.Sensoryandchemicalanalysisshowedthesmoketohaveacumulativeeffectonthelevelsofsmoke-relatedcompoundsandaromasinresultantwines(Kennisonetal.2008).Therefore,repeatedsmokeexposureorexposureforalongperiodresultsinaccumulationofsmokearomasandcompoundsinthefinalwine.

Potential carry-over of smokeGrapevineswereexposedtoeightsmokeapplicationsfromveraisontoharvest(Kennisonetal.2011).Winefromthisfruitcontaineddistinctaromasofsmokedmeat,burntrubber,leatheranddisinfectant/hospital.Oneyearlaterfruitfromthesamevineswasharvested,madeintowineandevaluated.Smoke-relatedaromasandflavourshadnotcarriedovertothenextseason.However,fruityieldwasconsiderablylower(6.4kilograms)thanvinesthatwerenotexposed(12.9kg).Repeatedsmokeexposurewasthereforelikely to affect grapevine function and its reproductive capability.

Effect on wine productionWineproductionwithsmoke-exposedfruitcanrequireadditionaltoolsandtechniquestoreducethedevelopmentofsmoke-likecharactersthroughoutthewinemakingprocess.Smoke-relatedvolatilephenolshavebeenshowntoaccumulateinmustduringfermentationandfurtheraccumulateaftermalolacticfermentation(Kennisonetal.2008).

Generally,therateoffermentationofgrapemustsisacceleratedwithsmoke-affectedgrapesandthesmoke-relatedvolatilephenolsfurtheraccumulateinthebottleovertimeandduringstorage(Kennisonetal.2008).

Thesephenolscanbereducedduringwinemaking,depending on how the fruit is handled and the wine fermentation.Techniquessuchashandharvesting,excludingleafmaterial,wholebunchpressing,separationofpressfractions,yeastselectionandreverseosmosishaveallbeenfoundtoreducesmoke-relatedaromas,flavoursandcompoundsinwine.TechniquestoreducesmokecharactersinwinearedetailedinTable1.

11

Smoke effect reduction system

Smoke Taint Risk calculator (STAR)Acomprehensivecomputer-basedsoftwaretoolhasbeendevelopedbyDAFWAandUWAtoreducetheincidenceandseverityofsmokeexposureongrapesandwine.Thetoolcanpredicttheseasonalvinephenological stage and associated susceptibility of the vinetosmokeuptakeandeffectonwine.Thistoolcanalsobeappliedinprescribedburningdecisions.The

SmokeTaintRiskcalculator(STAR)isavailableontheDAFWAwebsiteatagric.wa.gov.au(exampleshowninFigure4).

STARincorporateselementsincludingvineyardlocationmapping,knowledgeofseasonalgrowthstages,smokeriskfactors,in-fieldsmokedetectingequipmentandaninteractivesoftwareinterface.Ithas unrestricted access and the website also contains informationonhowtousethesoftware.

Figure 4ExampleofsmokeriskprofileproducedbySTARforMerlotinthePembertonregion2011–12.

12

Vineyard location mappingVineyardsoccuroverdiverselandscapesandlargegeographicalareas.TheyarepredominantlyinrecognisedGeographicalIndications(GI)regionsthatareformallyestablishedtoencompass regional wine grapeproduction.Ingeneral,mostproductionisinrecognisedGIregions,howeversomevineyardsmaybeoutsidethem.

Wineproductioncancoverlargeareasadjacenttootheractivitiessuchashorticulture,agriculture,forestryandurbandevelopment.Aspartofthesmokeriskreductionmodel,itisimperativetoknowwhere vineyards are located and their heaviest concentrations.Thisisofkeyimportancetomanagecompetingactivitiesandscheduleprescribedburnstoavoidconflictswithwinegrapeproduction.

Knowledgeofvineyardlocationsisessential where ownersneedtobecontactedifsmokeorbiosecurity

issuesarise.Whenfiresdooccur,thespreadofsmokecan be tracked by aerial photography to see if it correspondswithwineproductionareas.

DAFWAhasdevelopedaprocesstocaptureandmapvineyardlocations.ThishasbeenpilotedinWAandcanbereproducedelsewhereinAustralia.ItincludessourcingaerialmapsfromLandgatethatareinspectedtoidentifyareasthatcontainvineyards(Figure5).

Eachvineyardisidentifiedanditsownerscontactedandprovidedwithahardcopymapoftheirpropertytoconfirmwinegrapeproduction.Allownersarerequestedtoprovidecontactdetails,areasofwinegrapeproductionandvarieties.Thisinformationisenteredintoacomprehensiveandsecuredatabase.Thelocationsofvineyardsareusedforcommunicationonpotentialsmokeeventsandinplanningprescribedburning.

Figure 5Exampleofaerialmapshowingawinegrapeproperty.

13

Timing of key growth stagesResearchhasshowntheriskofsmokeuptakeanddevelopmentvariesdependingonthevinegrowthstage.Therefore knowledge of the true phenological growthstagecandeterminethepotentialrisks.Timingofgrowthanddevelopmentishighlydependentontemperature,withvariabilityofstagesduetoclimate,region,seasonalconditionsandvariety.

In order to gain a greater understanding of seasonal variabilityofgrowthstages,apilotstudywasconductedinWA.Researchersobtainedhistoricalphenologicalrecordsfromproducersandseasonalrecordsfrom2011to2012.Resultsshowedthetimingof key growth stages varied greatly between regions andevenwithinaregion.Thisinformationisimportantandneedstobeconsideredateachsitetodeterminethetruetimingofgrapevinesensitivitytosmokeuptake.

Calculation of smoke risk factorsSmokeriskfactorsincorporatedintotheSTARmodelhavebeenbasedonfieldresearchandgeneratedfromboththechemicalandsensorysmoke-relatedpropertiesofwine.ItcoverskeyvarietiesincludingMerlot,CabernetSauvignon,ChardonnayandSauvignonBlanc.Thenumberofvarietieswillincreaseasresearchprogressesinthisfield.

Smoke detection in the field (nephelometers)Understandingthetimingofsmokeexposureanditsassociateddensityanddurationprovidesinformationonthelikelihoodoftaintinthefinalwine.Inorderto

identifyifsmokehasbeenpresentinthevineyard,smokedetectionequipmentcanbeemployed.

Anumberofreliableunitsareavailable,includingparticulatemonitors,atmosphericgasdetectors,nephelometersandvisualmonitors(webcameras),allwithavarietyoffunctions.

InrecentDAFWAresearch,nephelometerequipmenthasbeenusedreliablytoquantifysmokepresenceinthevineyard(Figure6).Nephelometersusealightdetectortomeasuresuspendedparticlesintheatmosphere,withthedensityoftheseparticlesrelatedtotheirlightreflectance(Figure3).

Foranysmokedetectionequipmentinthefielditisimportanttoconsideritsfunction.Cost,portability,weatherstability,powersource,datadownloadcapability and data interpretation also need to be considered.

Figure 6Exampleofportablenephelometerusedtodetectsmoketiming,densityandduration.

14

In case of a smoke event in the vineyard …damagingtowinegrapeproduction.However,firescanstillconflictwithgrapeproduction,especiallyduring later seasons when fruit production coincides withautumnfires.

Stateforestmanagementdepartmentsmayconductmanagementactivitiesthatproducesmoke,includingprescribedburning.InWA,theDepartmentofEnvironmentandConservation(DEC)conductsyearlyprescribedburnsinspringandautumn.Theseareundertaken for a variety of purposes that include:

• reductionofforestfuelloadstominimisewildfires

• protectionoflife,propertyandthecommunity

• enhancementofbiodiversityvalues

• torehabilitatevegetationaftertimberorminingactivities

• toresearchfireeffectsandfireinteractionwiththeenvironment.

Smokeeventscanbefrequentandarisefromanumberofsources.Itwouldbeidealtoavoidsmokeexposureofgrapevinesduringthegrowingseason,howeverthisisnotpossibleintheAustralianlandscape.Itisthereforeimperativethatactionsandtechniquestopracticallyreducethenegativeeffectsofsmokeexposureofwinegrapesaredeveloped.Theseactionscanbeusefulifasmokeeventisimminent,ifafuel-reductionfireisplanned,oraneventhasoccurred.

If a smoke event is imminent

Seasonal prescribed burn informationFirescanbeplannedorunplanned.Plannedfires,orprescribedburns,maybeconductedbyforestmanagementagencies,localshires,localandvolunteerbushfirebrigadesandlandholders.Lightingfiresisrestrictedduringsummerwhensmokeismost

15

DECusesaMasterBurnPlaninordertoidentifytheareasrequiringprescribedburningforthecomingyearand to indicate the burning schedule for three years ahead.Informationonthetimingofprescribedburnsiscommunicatedwidelytoindustryandthecommunity.ThisinformationisreadilyavailablefromtheDECwebsite at dec.wa.gov.au or by phoning +61(0)864675000.Inotherstates,contactyourrelevantforestmanagementdepartment.

Registration of sensitive sites‘SensitiveSitesWA’isaDAFWAservicedesignedtohelplocatesensitiveagriculturalproductionsystemswithin theagriculturalregions.AsensitivesiteisdefinedasapropertywhoseownerandDAFWAbelievemaybesensitivetoimpactfromactivitiesonnearbyland.Thisserviceaimstoassistwithriskassessmentandriskmitigationplansforongoingproduction and to help protect sensitive agricultural productionsystems.

Examplesofasensitivesitemayincludeproductioncertifiedasorganicand/orbiodynamicandviticulture.Specificexamplesofactivitiesonneighbouringlandsthatareknowntoimpactonwinegrapeproductioninclude:

• Smokeeffectingrapesandwinefromplannedandunplannedfires

• Off-targetspraydriftdamage

• Eucalyptuscharacteristicsinwinefromadjoiningbluegumplantations

• Pestanddiseaserisksfromneglectedvineyards.

Propertiesidentifiedassensitivesitesaredefinedonamapthatisaccessibleat agric.wa.gov.au/PC_94554.html?s=1295170843.

If you wish to register interest to include your property emailsensitivesites@agric.wa.gov.au or phone +61(0)893683333.

Formalising end of harvest datesInordertoreducepotentialconflictsbetweensmokeevents and wine grapeproduction,manystrategiescanbeemployed.Producerscancommunicatekeyvinegrowthstagesregularlytoforestmanagementagenciesandlocalshires,particularlyripeningtiming,toreducepotentialconflicts.

Ideally,centralcommunicationpointscouldbeestablishedineachregiontodisseminateinformation,wherebothformalandinformalcommunicationcanbeemployed.Thesestrategieswouldbeindividualtoeach region and could include:

• Regionalwineproducinggroupstoregistertheirinterestincommunicatingendofharvestdateswithlocalshiresandforestmanagementagencies

• Organisationofacentralcommunicationpointwithin each agency involved

• Wineproducerstoprovideregular(weekly)feedbackontheprogressandtimingofharvestdates to their regional association

• Centralcommunicationpointstocollectendofharvesttimingfromgrapeproducersandcommunicatethesetoforestmanagementagencies and local shires

• Centralcommunicationpointtoprovideregularfeedbackandcommunicationbetweenforestmanagementagencies,localshiresandwinegrapeproducers.

16

If a smoke event has occurred

Sampling, sending and testing of grapesFollowingasmokeevent,oneoptionistohavesamplestestedforthepresenceofthesmoke-relatedmarkercompoundssuchasguaiacol,4-methylguaiacol,cresolsandsyringols.

Samplescanincludegrapeberries,grapejuice,leavesandwine.Testingofgrapesandjuicecanindicatewhetherthefruithasbeenexposedtosmoke.Lowlevelsofthesecompoundscanbenaturallypresentinfruit,withtheselevelselevatedinsmoke-exposedfruit.

Guaiacoland4-methylguaiacoldetectioninfruitcannotbeusedasadeterminantofthesmoke-effectintensityinthefinalwineasthisisinfluencedbyfruithandlingandprocessing.Ifyouareconcernedthatgrapesmayhavebeenaffectedbysmoke,samplingisbestdoneasclosetoharvestaspossible.Testingmaybeineffectiveongrapessampledearlier.

Testinglaboratoriesmayinterprettestresultshowevera‘bench-top’or‘small-lot’fermentationofgrapespriortoharvestissuggestedtoindicatesmoke-effectintensityinthefinalwines.Researchisongoingtodeterminemoreeffectiveanalysisofgrapesforthepresenceofsmoke-relatedcharacters.

Whentakingsamples,collectionoffruitandvinematerialshouldbedoneearlyinthedaypriortohightemperaturesandvinestress.Samplesshouldbetaken across the entire vineyard area and be collected randomly.Samplesshouldbekeptcool,andfrozeniftobepostedinterstate.

PlantHealthCertificatestofacilitatequarantinerequirementsformovementofgrapevinematerialinterstateareoftenrequiredandcanbeobtainedfromtherelevantStateDepartmentsofAgriculture/PrimaryIndustry.Forinstance,aPlantHealthCertificateisrequiredformovementofplantmaterialfromWAtoeasternAustraliaandcanbeobtainedfromQuarantineWAbyphoning+61(0)893341800.

Anumberoflaboratoriesoffertestingforthepresenceofsmoke-relatedcompoundsingrapevinesamples.ManyareineasternAustraliaandincludeTheAustralianWineResearchInstitute,+61(0)883036600andVintessentialLaboratories,1300652342.

Additionallaboratoriesmayanalysesmoke-relatedcompoundsandtheseservicesvaryinlocation,costandtype.Incasesofextremesmokeexposureofanentireregion,acentralcollectionpointisoftenorganisedbystategovernmentstomovematerialfortestinginterstate.

Techniques to reduce smoke effectAftersmokeexposureoffield-growngrapevines,anumberoftechniquescanbeemployedinboththevineyard and winery to reduce the concentration of smoke-relatedaromas,flavoursandcompoundsinthefinalwine.ManyaredetailedinTable1andaremoreeffectivewhenusedincombinationratherthanalone.

17

Table 1 Techniquestoreducesmoke-relatedaromas,flavoursandcompoundsduringhandlingandprocessinggrapesandwine.

Technique Details

Hand harvest fruit Minimisebreakingorrupturingofskinsaslongaspossible1,2

ExcludeleafmaterialLeafmaterialcancontributesmoke-relatedcharacteristicswhenincontactwithfruitandjuice1,2

Wash grapevinesCanopyleafpluckingfollowedbyhigh-pressurecoldwaterwashinthevineyardcanremoveash7,howeverwashingtheentirecanopy(includingleaves)canaccentuatesmokecompoundsinfruit8

Maintainstructureofharvested fruit

Fruitmacerationandskincontactwithjuicecanleadtohigherconcentrationsofsmoke-relatedcompounds2

KeepfruitcoolFruitprocessedat10°Chadlessextractionofsmoke-relatedcompoundsthanfruitprocessedat25°C1,2

Whole bunch pressThishasbeenshowntoreduceextractionofsmoke-derivedcompoundsparticularlyin whites1,3

Separate press fractionsSmokecharacterscouldbeminimisedinthefirst400L/twhencombinedwithfruitcooling.Free-runjuicecancontainfewersmokecharacters1,2,3

Conductfiningtrialsbeforefermentation

Carbon,PVPPandisinglasshaveshownvariableeffectivenessinreducingsmokecharacteristicsbutarenotselective.Fermentationmanagementrequiresfurtherconsiderationafterfining1,2,3

ConsideryeastselectionSomeyeaststrainscanaltersmoke-relatedaromas,flavoursandchemicalcompositionofwine4

Minimisefermentationtimeon skins

Fermentationthatreducesskincontacttimecanreducesmokearomasandflavours1,4,5

Consideradditionofoakchips and tannin

Oakchipscanreduceintensityofsmokecharacteristicsthroughincreasedwinecomplexity4

ReverseosmosisofwineReverseosmosiscanbeeffectiveinsmokereduction,howevertaintwasfoundtoreturninthewineovertime6

Marketwineforquicksale Smoke-relatedcharacteristicscanevolveinbottleaswineages1,3,6

1Simos2008,2WhitingandKrstic2007,3Ulrich2009,4Ristic2011,5Kennisonetal.2008,6Fudgeetal.2011, 7Højetal.2003,8Kennison2009.

18

Management of fire-damaged grapevinesDuringafire,grapevinesmaybephysicallydamagedbyflamesand/orbyradiantheatfromthefire.Oftenboththephysicaldamage(Figure7)andradiantheatdamage(Figure8)mayappearsimilarandrangefromslightscorchingofleavestocompletedestructionofthevine.

Firemaydamageallgrapevinestructuresandresultininjuryordeathofleaves,leafpetioles,budsoncanesandshoots(includinglatentbuds),floweringand fruit production organelles and the vascular system.Dependingonthedegreeofdamage,vinesmayrecovertofullfruitproductionorbeirrevocablydamagedanddie.

Atanygivenvineyardsite,firedamageisofteninconsistentandhighlyvariable.Weatherconditions,fireferocityandthegrowthstagecanallcontributetothedegreeofvinedamage.Alimitednumberofinvestigationsofgrapevinesfollowingfirehavefocusedonassessingtheimmediatedamageandapplyingpruningtreatments.Usefultechniquesforassessmentofgrapevinesafterfiredamageinclude:

• Visual vine assessment: To be conducted immediatelyafterthefireandincludeassessingdamagethatmaybe‘nil’(novisibledamage),‘low’(suchasminorleafscorch),‘medium’(damagetoleaves,inflorescence/fruit)or‘high’(severescorchinganddamagetoallplantpartsfromcontactwithflames).Visualassessmentshould

Figure 7PhysicalfiredamagetoChardonnayvines. Figure 8Radiantheatdamagetograpevines.

19

be based on individual varieties and record the locationofvinedamagewithinablock.

• Cambium assessment:Asmallknifeincisioninthetrunkcanbemadetoinvestigatethecolourofthecambiumtissue.Healthytissueismoistandgreen,damagedtissueisdryandpale,whiledeadtissueisdryandbrown(Whiting2011).

• Trunk staining: This was investigated by Scarlett etal.(2011)wheretransectsectionsoftrunkarecutandstainedwithmethyleneblue.Ifthesegmentisbrightbluethenthetissueis‘viable’,ifthetrunksegmentisadirtyblueorbrownthenthetissueis‘unviable’.Thismethodisdestructivetothevines,howeverprovidesanimmediateindicationofthefire’seffect.

• Bud dissection:Canprovideindicationofviabilityand potential fruitfulness of buds within cane material.Withamicroscope,dissectionofbudsindicateswhethertheyarealive(green)ordead(brown/black).Dissectionisbestconductedpriortowinterpruninginordertoprovideinformationontheoptimalnumberofbudstoretainonthevineandtheirpositionwithinthecanopy.

Aftercomprehensiveassessmentofgrapevinesafterfiredamage,anumberofmanagementtechniquescanbeemployedtoaidrecovery.Techniquesdependontheseverityofdamagethatincludes:

• No damage:Continuevinemanagementasusual,payingattentiontograpevinehealth,andapplyadditional irrigation to vines that show heat stress symptomsfromthefire.

• Low damage:Continuevinemanagementasusual,applyingadditionalirrigationafterthefire,and consider a pruning strategy to investigate (buddissection)andretainviablebudsduringvinedormancy.

• Medium damage: Apply irrigation as soon as possibleafterfire.Monitorvinesforstressandfurthersignsofdecline,andinvestigatehealthstatusofcambiummaterialintrunks.Investigatebudfruitfulnesspriortodormantpruningasadditionalbudsmayneedtoberetainedtoencouragegrowthandfruitfulness.Vinefruitfulnessmaybeimpactedinthefollowingseasonandadditionaltrainingofreplacementvineshoots,arisingfromthecrownandcordon,mayberequired.

• High damage:Likelihoodofsurvivalislow.Vinesshouldbeirrigatedtoencouragerecovery,howeverdestructivemethodsofsurvivalassessment(trunkstaining)wouldprovideanimmediateindicationofviability.Grapevinesmaybeminimallyprunedtoencourageshootgrowthin viable buds and further assessed for survival inthefollowingseason.Replantingorgraftingofunproductivevinesmayberequired.

Applyingirrigationisacommontreatment,howevermaybedifficultifirrigationlineshavebeendamagedfromthefire.

20

ReferencesFudge,AL,Ristic,R,Wollan,D&Wilkinson,KL2011,Ameliorationofsmoketaintinwinebyreverseosmosisandsolidphaseadsorption.Australian Journal of Grape and Wine Research17(2),S41–S48.

GWRDC2009,Smokeeffectsingrapesandwine:managingqualityinachangingclimate.GrapeandWineResearchandDevelopmentCorporation,SouthAustralia.

Høj,P,Pretorius,I&Blair,R(eds)2003,TheAustralianWineResearchInstituteAnnualReport,Adelaide, pp.37–39.

Kennison,KR2009,Bushfiregeneratedsmoketaintingrapesandwine.FinalreporttoGrapeandWineResearchandDevelopmentCorporation,RD05/02–3.

Kennison,KR,Gibberd,MR,Pollnitz,AP&Wilkinson,KL2008,Smoke-derivedtaintinwine:thereleaseofsmoke-derivedvolatilephenolsduringfermentationofMerlotjuicefollowinggrapevineexposuretosmoke.Journal of Agricultural and Food Chemistry56, 7379–83.

Kennison,KR,Wilkinson,KL,Pollnitz,AP,Williams,HG&Gibberd,MR2009,Effectoftiminganddurationofgrapevineexposuretosmokeonthecompositionandsensorypropertiesofwine.Australian Journal of Grape and Wine Research15,228–237.

Kennison,KR,Wilkinson,KL,Pollnitz,AP,Williams,HG&Gibberd,MR2011,Effectofsmokeapplicationtofield-grownMerlotgrapevinesatkeyphenologicalgrowthstagesonwinesensoryandchemicalproperties.Australian Journal of Grape and Wine Research17(2),S5–S12.

Kennison,KR,Williams,HG&Gibberd,MRinpreparation,Thedensityanddurationofsmokeexposuretograpevinesinfluencesthedevelopmentofsmoke-likecompounds,flavoursandaromasinresultantwine.

Ristic,R,Osidacz,P,Pinchbeck,KA,Hayasaka,Y,Fudge,AL&Wilkinson,KL2011,Theeffectofwinemakingtechniquesontheintensityofsmoketaintinwine.Australian Journal of Grape and Wine Research17(2),S29–S40.

Scarlett,N,Needs,S&Downey,MO2011,Assessingvineyardvariabilityafterbushfire.The Australian and New Zealand Grapegrower and Winemaker564,January21–25.

Simos,C2008,Theimplicationsofsmoketaintandmanagementpractices.Australian ViticultureJan/Feb77–80.

Ulrich,T2009,Whenthesmokecleared:Californiawinemakersfacetoughpre-bottlingdecisionsfor2008wines.Wines and VinesJuly46–52.

Whiting,J2011,Grapevinerecoveryfromfiredamage.PosterabstractinProceedings of the 14th Australian Wine Industry Technical Conference,Adelaide,3–8 July2010,RBlair,TLee,SPretorius(eds).

Whiting,J&Krstic,M2007,Understandingthesensitivitytotimingandmanagementoptionstomitigatethenegativeimpactsofbushfiresmokeongrapeandwinequality–scopingstudy.DepartmentofPrimaryIndustries,Knoxfield,Victoria.

2013

3408

-07/

13

DepartmentofAgricultureandFood,WesternAustralia

3Baron-HayCourt,SouthPerth,WesternAustralia

Postaladdress:LockedBag4,BentleyDeliveryCentreWA6983

Tel:+61(0)893683382Fax:+61(0)893677389

agric.wa.gov.au