Processing-of-Green-Tea

商务部援外项目,绿茶加工技术ProcessingofGreenTea,ByZhangYanliDepartmentofTeaSicence,TeaCollege,绿茶是一种未经发酵的茶叶，品质特点为“清汤绿叶”。Greentea,onekindofnon-fermentedtea,bearsthecharacteristicsofclearteasoupandgreenleaves.,珠茶Gunpowdergreentea,蒸青绿茶Steamedgreentea,机器采摘pluckedbyMachine,人工采摘pluckedbyHands,嫩度匀度新鲜度,Tip,One-tipone-leave,One-tiptwo-leave,One-tipthree-leave,鲜叶分级机Machineforfreshtealeavessorting,离体鲜叶保持原有理化性状的程度，称为新鲜度，它是鲜叶质量的重要指标之一。Freshness,oneoftheimportantqualityindexesoffreshtealeaves,referstothedegreeoforiginalphysicalandchemicalpropertiesoffreshtealeaves.,一般而言，鲜叶新鲜度高，毛茶质量好。因此，生产上要求鲜叶现采现制或较短的时间内付制。Ingeneral,iftealeavesareinhighfreshness,thequalityofprimaryteaissuperior.Therefore,itsrequiredthatthemomenttheyareplucked,thefreshtealeavesshouldbeprocessedintime.,红变鲜叶Bad,正常鲜叶Fresh,TurningRed,鲜叶新鲜度的感观评判标准：一看叶色有无红变，即使只有少量红变，也表明该批鲜叶有劣变。二嗅香气，新鲜度好的鲜叶具有兰花清香或清爽香；若嗅到浓气味，说明鲜叶新鲜度中等；若嗅到酒精味，恶气、腐料气味则表明新鲜或变质。,Thesensorycriteriaoffreshnessoftealeaves:1)Lookatthecoloroftealeaves.Ifthetealeavesturnslightlyred,itshowsthattheyaredeteriorating.2)Smellthefragranceoftealeaves.Thetealeavesinhighfreshnesssmelllikeorchidorrefreshing.Iftheysmellstrongodor,itindicatesthatthetealeavesareinmediumfreshness.Iftheysmelllikealcoholorfoulodor,itshowsthattealeavesaredeteriorating.,鲜叶从茶树上采下后，其内含物仍进行着激烈的理化反应，如Vc含量减少，多酚类化合物的氧化，碳水化合物的呼吸消耗。Aftertheyarepluckedfromteatrees,theinclusionsoffreshtealeavesarestillengagedinastateofintensebiochemicalreactions,suchasthereductionofVitaminCcontent,theoxidationofpolyphenolcompounds,therespiratoryconsumptionofcarbohydrates.,在大规模生产的高峰期，鲜叶很难做到现采现制，鲜叶就要贮藏保鲜，特别是夏季，气温高，鲜叶因保管不善而腐烂，或者降级处理造成的经济损失是常见的事。因此，鲜叶的贮藏保鲜技术是十分重要的。Sinceinthepeakperiodofmassproduction,itsquitedifficulttoprocessallthefreshtealeavespluckedintime,storageandpreservationoffreshtealeavesshouldbecarriedout,especiallyinsummer.Itscommonthatfreshtealeavesarerottenordegraded,whichwouldbringabouteconomiclossduetothebadpreservationoftealeaves.Therefore,thetechnologyofmaintainingtealeavesinfreshnessisofgreatimportance.,Themainfactorsoffreshtealeavesdeterioration:,Poorventilation,HighTemperature35,Mechanicaldamage,Techniquesforkeepingtealeavesinfresh:,2.炒青茶初加工PartII.RoastedGreenTeaPrimaryProcessing,杀青是绿茶初制的第一道工序，是形成和提高眉茶品质关键性的技术措施，其目的是利用高温破坏鲜叶中酶的活性，阻止茶多酚的酶促氧化以及叶子内含物质不必要的变化，使叶质变软，便于揉捻成条，同时散失部分水分，促进香气的形成。,Fixation,the1stprocessingreenteaprimaryprocessing,isancriticaltechnicalmeasuretoformandimprovethegreenteasquality.Anditaimstodestroytheenzymeactivityoffreshtealeaveswithhightemperature,topreventtheenzymaticoxidationofteapoly-phenols,aswellastopreventunnecessarychangesofleaveinclusions.Inthisway,thetealeaveswillbesoftenedtorollintostrips.Atthesametime,partialmoisturewillevaporate,andthenthefragrancewillbeformed.,1.杀青方法FixationMethods（1）锅式杀青PanFixation,锅温PanTemperature,杀青温度切忌忽高忽低。Thetemperatureshouldbestableinsteadofgoingupanddownabruptly.,在一般正常操作下，晴天嫩叶下锅后有炒芝麻响声。Usually,whentenderleavesareputintothepanonsunnydays,thereisasoundlikesesameisfried.,老叶下锅后有较响爆炸声。雨水叶，露水叶表面水多，锅温必须在260270以上。Whenoldtealeavesareputintothepan,thereisaloudexplosivesound.Astherearemoremoistureonthesurfaceoftealeaveswhicharepluckedinrainyordewydays,thepanningtemperatureshouldbeabove260270.,如锅温高，投叶量可适当多些，使锅温下降，反之则少些，雨露水叶比晴天的叶子少些，老叶则比嫩叶少些。Forinstance,ifthepantemperatureishigh,wecanincreasethequantity.Ontheotherhand,ifthetemperatureislow,weshouldreducetheamount.Besides,iftealeavesaretooold,weshouldreducethequantity.Andiftealeavesaretender,wecanputmoreinit.,投叶量Thequantityoffreshtealeaves,在正常锅温的条件下，投叶量一般掌握在57kg范围内，但应根据锅温，原料老嫩，叶表面水多少等条件灵活掌握。Undernormalpantemperature,thetealeavesquantityrangesfrom5to7kg.However,thequantityshouldbeflexibleaccordingtothepantemperature,therawmaterialconditions,thewatercontentontheleafsurfaceandsoon.,时间Time,杀青要求高温快速，在杀匀、杀透的原则下，尽可能缩短时间，才能提高杀青叶的质量。Itsrequiredthatfixationshouldbecarriedoutfastunderhightemperature.Thefixationtimeshouldbeshortenedasmuchaspossibletoenhancethequalityoffixation.,杀青时间长短受锅温、投叶量、炒法、原料等各种因素的影响。一般晴天嫩叶78min，老叶56min，雨露水叶10min左右。Thefixationtimeisrelatedtothefollowingfactors:thepantemperature,therawmaterialquantityandsoon.Ingeneral,thefixationoftendertealeavestakes78min,oldtealeaves56min,thetealeaveswithdewaround10min.,杀青时间长，杀青叶的色泽、香气都受到影响。因此，在生产实践中，必须正确掌握好锅温高低和投叶量多少，以保证杀青叶质量。Iffixationtimeistoolong,thecolorandfragranceoftealeavesareaffected.Therefore,wemustcorrectlyregulatethepantemperatureandthetealeavequantity,toensurethefixationqualityinpractice.,杀青方法FixationMethods,在一般情况下，晴天嫩叶下锅后先透气再焖炒12min。当看到大量水蒸气从锅里冒出来，即进行透炒至适度。Generally,onsunnydays,thefreshleavespluckedshouldbespreadoutafterbeingputintothepan,andbeclosingfriedfor12min.Whenmassivesteamisevaporatedfromthepan,thoroughfryingcanbecarriedoutmoderately.老叶和摊放时间长的叶子，下锅焖杀3min左右再透炒。Iftealeavesareoldorspreadoutforalongtime,theyshouldbeclosingfriedforabout3minbeforebeingfriedthoroughly.,细嫩茶叶，雨水叶则全程透炒。Forthetenderonesandthetealeaveswithdew,theyshouldbefriedthoroughlyfromthebeginningtotheend.表面水不多的露水叶，先透炒23min待水分蒸发一部分后，焖杀11.5min，再透炒至适度。Iftherearenotsomanydropsofdewontheleafsurface,theyshouldbefriedthoroughlyfor23mintoevaporatepartialmoisture.Andthenclosingfryingcanbecarriedoutfor11.5min.Finally,thoroughfryingcanbecarriedoutagainmoderately.,（2）瓶式杀青机Bottle-typedfixationmachine,200,（3）滚筒杀青机Cylinder-typedfixationmachine,筒体cylinder,炉灶stove/cookingrange,输送Feeding/conveying,筒体内部导板cylinderinternalguideplate,杀青叶质量的好坏，是决定眉茶品质的重要环节。Thegreenteaqualityisaffectedbythefixationtealeafquality.杀青叶适度的判断方法：Themethodsofjudgingfixationdegree:一是以杀青叶外观叶象来表示，二是以杀青叶减重率或杀青叶含水量来表示。1)Havealookattheappearanceoftealeaves.2)Judgefromtheweight-lossrateorthewatercontentoffixationtealeaves.,2.杀青程度FixationDegree,杀青叶适度的主要标志是：Mainfeaturesfortealeaveswithmoderatefixationareasfollows:叶色暗绿，叶面失去光泽，叶质柔软，萎卷，折梗不断，手捏成团，松手不易散开，略带有粘性，青草气消失，清香显露。Tealeaveslookdeepgreenwithoutlusterontheleafsurface.Theybecomesoftandwithering.Theycanberolledintoaball,andwhenweopenourhands,theyarenotliabletospread.Theyareslightlystickywithdelicatefragrancebutwithoutgreenodor.经过杀青后，叶子含水量一般在60%左右，但因叶片老嫩程度存在差异，杀青叶水分可有一定的差异，一般要求杀青后老叶含水量控制在6062%，嫩叶在5860%。Thereisabout60%watercontentleftafterfixation.Howeverthemoisturearedifferentfortenderfixationtealeavesandoldones.Itsrequiredthat,afterfixation,themoistureofoldtealeavesshouldbecontrolledbetween6062%,whiletenderonesbetween5860%.,Freshleaves,Afterfixation,Afterfixation,二、揉捻（Rolling）,杀青叶出锅后，应立即抖散薄摊于干净的场所冷却，或者用冷风迅速吹冷。Afterfixation,theleavesshouldbespreadoutthinlyoncleanplacesforcoolingorcooledbycoldwind.经过冷却后再揉捻的叶色翠绿，香高味醇。Iftealeavesarecooledbeforerolling,theywilllookbrightlygreenwithstrongfragranceandmellowtaste.,1.揉捻的目的RollingObjectives,揉捻是塑造外形的重要工序，常在揉捻机中进行。Rollingisacrucialprocessforshapingtheappearance.Itisoftencarriedoutinarollingmachine.揉捻的目的有二：Therearetwoobjectives:卷紧茶条，缩小体积，为炒干成条打好基础；Totightenteastripsandnarrowthesize,inordertolayagoodfoundationforfryingintostrips.适当破坏叶组织，既要茶叶容易泡出，又要耐冲泡。Todestroythetissueoftealeavessothatthesoluteoftealeavescanbebrewedout.,Roller,2.操作技术与要点OperationTechniques,眉茶揉捻时，要求五要五不要：Therearefiverequirementsforgreentearolling:一要叶条，不要叶片；1)Stripsonly,noblades;二要圆条，不要扁条；2)roundstrips,noflatones;三要直条，不要弯条；3)straightstrips,nocurvedones;四要紧条，不要松条；4)tightstrips,nolooseones;五要整条，不要碎条。5)completestrips,nobrokenones.同时，要求叶色翠绿，不泛黄，香气清高，不低闷。Atthesametime,tealeavesshouldlookbrightlygreeninsteadofyellowish.Andtheyshouldsmellfragrantinsteadofstuffy.投叶量、时间和压力，是揉捻工序的主要技术因子。Thetealeavequantity,durationandpressure,aremajortechnicalfactorsduringrolling.,（1）投叶量Thequantityoffreshtealeaves,各种型号的揉捻机，都有一定的投叶适量范围。Thereisaquantityrangeforvarioustypesofrollingmachines.投叶量的多少，直接关系到揉捻质量的工效。Thequantityisdirectlyrelatedtotherollingefficiency.如揉捻叶过多，则出现下列情况：Ifthereareexcessivetealeaves,thenthefollowingsituationswilltakeplace:,开动揉捻机时，往往由于叶子翻转冲击揉盘，或由于离心力的作用，叶子因过满而甩出桶外，甚至发生事故；Whenrollingmachinesstarttowork,tealeavescouldbethrownoutofthecylinderduetocentrifugalforce.Sometimes,accidentsmaytakeplace.叶子过多，叶子在揉桶内翻转困难，揉捻不均匀，不仅条索揉不紧，还会造成松散条和扁碎多；Itsdifficultfortealeavestoturnoverinrollingcylinder,whichleadstounevenrolling.Asaresult,thestripsarenottight.Itwillresultinloosestripsandflatorbrokenones;因叶子与叶子、叶子与揉桶、叶子与揉盘之间摩擦增大，发热，不仅影响外形，也会影响内质。Thereisanincreasingfrictionbetweentealeavesandtealeaves,tealeavesandrollingcylinder,whichwillgiveoffheat.Asaresult,theappearanceandqualityofteawillbeaffected.,如揉捻叶过少，叶间相互带动力减弱，不易翻转，也起不到揉捻的作用。However,ifthereareinsufficienttealeaves,themutualdriveforcebetweentealeaveswillbeweakened,andthenitsnoteasyfortealeavestoturnover.因此，必须根据揉捻机的型号，确定投叶量，一般装到比揉桶浅34cm处即可。Therefore,thequantityoftealeavesshouldbebasedonthemodelofrollingmachines.Ingeneral,thereshouldbe34cmofspaceleftintherollingcylinder.,（2）揉捻时间和加压Rollingdurationandcompression,关于加压的具体方法，应按“先轻后重，逐步加压，轻重交替，最后不加压”，即“轻-重-轻”的原则，即：Specificcompressionmethods:lightcompressionfirstandheavycompression,andthencompressgradually,alternatewithlightcompressionandheavyones,finallynocompression.在揉捻开始阶段，一般不加压，通过轻轻的搓揉，使叶片能逐步沿着叶子主脉初步卷成条胚；Atthebeginningofrolling,onlylightrollingisallowedwithoutcompression,sothatbladescanberolledintoinitialstripsalongthemainveinoftealeaves.,当叶子在揉桶内能上下滚动，此时可开始加压。Whentealeavesarerolledupanddownincylinder,thecompressioncanbedone.加压的轻重，应视叶子的老嫩而定，嫩叶应以无压柔捻为主，中间适当加轻压；Compressiondegreeisbasedonthetendernessoftealeaves.Iftealeavesaretender,rollingshouldbenon-pressure-orientedwithsuitablelightcompressionduringtherolling.老叶要加重压，但应逐步加重，开始无压，中间加压，最后又松压。Iftealeavesareold,heavycompressionshouldbecarriedoutwithincreasingpressuregradually,thatisnocompression,compressionandde-compressionfinally.,中等嫩叶：共揉3040min：轻10min，重压1525min（中间松压23次），松压5min后下机。Mediumtenderleaves:rollingfor3040minintotal:lightrollingfor10min,heavycompressionfor1525minwithde-compressionfor23timesduringtherolling,5minafterde-compression,tealeavescanbeputout.,揉捻时间一般为RollingDuration：嫩叶：共揉2025min：轻10min，加压510min，解压后再揉5min。Tenderleaves:rollingfor2025minintotal:lightrollingfor10min,compressionfor510min,afterthecompression,rollingagainfor5min.,老嫩混杂叶：开始按嫩叶要求进行，然后用11cm筛子进行抖筛筛分，筛下叶子进行干燥，筛面叶子视情形复揉。Mixedleaveswithyoungonesandoldones:atthebeginning,themethodisthesameasthatoftendertealeaves.Andthentheyshouldbescreenedbyasifter.Thetealeavessievedoutofthesiftercanbedried,andthetealeavesleftonthesiftercanbere-rolledagain.,（3）热揉与冷揉Heatedrollingandcoldrolling,热揉的叶色易变黄，并有水闷气。Thetealeaveswithheatedrollingareliabletoturnyellowandsmellstuffy.因此，较嫩叶子，应冷揉；对较老叶子，应热揉。Therefore,coldrollingissuitablefortendertealeaves;whileheatedrollingforoldones.,热揉是指杀青叶不经摊凉即趁热揉捻，冷揉指杀青叶经摊凉一段时间后再揉捻。Heatedrollingreferstocarryoutrollingwhenfixationtealeavesarestillhotwithoutcooling,whilecoldrollingreferstocarryoutrollingafterfixationtealeaveshavebeenspreadoutforcooling.,对一般的一芽二、三叶，属中等嫩度，应用温揉。Asforone-tiptwo-leafandone-tipthree-leaf(mediumtenderness),mediumrollingwouldbecarriedout.,3.揉捻程度RollingDegree,Evenrolling,above90%oftendertealeaveshavebeenrolledintostrips,morethan60%ofthelow-leveledoldleaveshavebeenrolledintostrips.,Cellbreakingrateliesbetween45-60%.Ifitismorethan70%,tipsandleavesarebrokenseriously.Asaresult,thefinishedproductstastebitterandastringentwithturbidliquorcolor.Andtheinfusiontimescanbealsoreduced.However,ifitislessthan40%,althoughtherearemanytimesofinfusion,theyareloosely-strippedandtheliquortasteweakandlight.,Thereisteajuiceadheringtotheleafsurface.Whenwetouchtealeaves,wecanfeelthattheyarestickyandhumidified.,三、干燥（Drying）,干燥是决定眉茶品质的最后一道工序，是眉茶整形、固定茶叶品质、发展茶香的重要工序。Drying,thefinalprocessdecidingthequalityofgreentea,isacrucialprocesstoshapetheappearance,fixthequalityanddevelopthefragrance.由于揉捻后叶子水分含量仍然很高，因此干燥时一般采用多次干燥，中间结合摊凉的方式进行。Sincetherearestilllotsofmoistureleftintealeavesafterrolling,dryinghastobecarriedoutmanytimes,duringwhichtealeavesshouldbespreadoutforcooling.眉茶的干燥一般分为三个阶段，即二青、三青（毛火）和足干（辉锅或足火）。Therearethreedryingstagesforgreentea,thatisthe2nddrying,3rddryingandthefinaldrying.,1.干燥的目的DryingObjectives,继续蒸发水分，使毛茶充分干燥，其水分含量要求6%以下，以防止霉变，便于贮藏；Themoisturecontinuestoevaporate,sothatprimaryteacanbefullydriedwithlessthan6%moistureleft,inordertobeconvenientforstorageandpreventfromgoingbad.彻底破坏叶中残余酶活性，保持绿叶清汤的品质特征，继续散发青臭气，促进一些内含成分的变化，巩固和发展茶香，增进滋味醇浓；Theleftenzymeactivitycanbethoroughlydestroyed,sothatthecharacteristicsofclearliquorandgreenleavescanbeensured.Andtealeavescancontinuetogiveoffgreenodortopromoteanumberofchangesintealeaveinclusions.在揉捻成条的基础上，进一步做成紧结、圆直、匀整的外形。Whentheyarerolledintostrips,dryingenablestealeavestobetightened,roundstraight,neatlyeveninappearance.,2.干燥技术与要点DryingTechniques,一般用烘干机烘二青，三青除了个别地区仍用瓶式炒干机（滚三青）外，大多数地区都用锅式炒干机（炒三青）。辉锅方法更不统一，有用瓶式炒干机辉锅的，也有用锅式炒干机的。Generally,the2nddryingiscarriedoutinabaker.The3rddryingisdoneinapan-typedfryingmachineinmostareas,andinbottle-typedfryingmachineinrarearea.Therearevariouswaysforthefinaldrying,forexample,inbottle-typedfryingmachine,inpan-typedfryingmachine.,干燥工艺：烘二青炒三青滚足干Dryingprocess:the2nddryingiscarriedoutbybaking.the3rddryingisfinishedthroughfryingthefinaldryingisdonebyfrying.,烘二青The2nddrying烘二青不能烘太干，否则二青叶一旦定型后，就很难再炒紧条索，但也不能太潮，否则也达不到二青的作用，二青叶下锅后仍会粘紧成团。Thereshouldbesomemoistureleftduringthe2nddrying.Iftheyaredriedwithoutanymoistureleft,itsdifficultfortealeavestobefriedintotightstripsagainoncetheirdesignsarefinalized.However,ifthereistoomuchmoistureleft,theywillsticktoeachotherwhentheyareputintopan.,进风口风温120130，摊叶厚度2cm，烘15min，至含水量在40%左右时下机。Theairtemperatureshouldbecontrolledbetween120130atairinlet.Tealeaves,spreadout2cmthick,shouldbebakedfor15minuntilthereisabout40%moistureleft.Andthentheycanbeputoutofthebaker.烘后的二青叶较潮，应及时摊凉散热。Thereisstillsomemoistureleftinthetealeavesafterthe2nddrying,sotheyshouldbespreadoutforcooling.,烘二青时，失水要适当，一般掌握在二青叶含水量在3040%为宜，烘后的二青叶，手捏有弹性，不易捏成团，但又不松散，稍有粘性。Dehydrationshouldbecontrolledappropriatelyduringthe2nddrying.Generally,thereshouldbe3040%moisturelefti