(42)--10.2 二次发酵：常被遗忘的青春之泉.pdf

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1、Secondary RefermentationThe Forgotten Fountain of Youth Scott J.BrittonASBC President 19-20Research&Development Scientist二次发酵：常被遗忘的青春之泉二次发酵：常被遗忘的青春之泉Secondary RefermentationThe Forgotten Fountain of Youth Scott J.BrittonASBC President 19-20Research&Development ScientistClick to Add TitleClick to add

2、 textProduction ProcessIngredientsthermal load,oxygen ingress,etc.TimeEstersIsohumulones&TerpenesAldehydes&KeytonesFlavor Stability is Impacted by a Myriad of FactorsTemperatureTimeSunlightClick to Add TitleClick to add text原料原料Ingredients热负荷、氧气进入等热负荷、氧气进入等thermal load,oxygen ingress,etc.Time酯类酯类Est

3、ers异葎草酮和萜烯异葎草酮和萜烯Isohumulones&Terpenes醛类和酮类醛类和酮类Aldehydes&Keytones风味稳定性受到诸多因素的影响风味稳定性受到诸多因素的影响Flavor Stability is Impacted by a Myriad of Factors生产工艺生产工艺Production Process温度温度Temperature时间时间Time日日光光Sunlight时间时间Click to Add TitleClick to add textOverview of Compounds Increasing in StorageCompoundOrig

4、inThreshold(ppb)DescriptionFurfuralMaillard15,000 15,157Caramel,breadyFurfuryl alcoholMaillard3,000,000Caramel,breadyDiacetylMaillard,yeast metabolism17 150Buttery2,3 pentanedioneMaillard,yeast metabolism900Buttery,cheesyAcetaldehydeOxidation of HA1,114 25,000Green Apple2-methylpropanalStrecker,Oxid

5、ation of HA86Grainy,Fruity3-methylbutanalStrecker,Oxidation of HA56 600Malty,Cherry,AlmondPhenyl acetaldehydeStrecker,Oxidation of HA105 600Hyacinth,Flowery,RosesBenzaldehydeStrecker515 2,000Almond,Cherry StoneMethionalStrecker4.2Cooked Potato,WortyTrans-2-nonenalFatty Acid Oxidation0,03 0,11Cardboa

6、rd,PaperyEthyl-2-MethylbutyrateAutolysis,Hop Oxidation7 27Fruity,Sweet,CandyEthyl-3-MethylbutyrateAutolysis,Hop Oxidation18 91Fruity,Sweet,CandyClick to Add TitleClick to add text贮藏过程中增加的化合物的概述贮藏过程中增加的化合物的概述Overview of Compounds Increasing in Storage化合物化合物Compound来源来源Origin阈值阈值Threshold(ppb)描述描述Desc

7、ription糠醛糠醛Furfural美拉德美拉德Maillard15,00015,157焦糖味、烤面包味焦糖味、烤面包味Caramel,bready糠醇糠醇Furfuryl alcohol美拉德美拉德Maillard3,000,000焦糖味、烤面包味焦糖味、烤面包味Caramel,bready双乙酰双乙酰Diacetyl美拉德、酵母代谢美拉德、酵母代谢Maillard,yeast metabolism17 150黄油味黄油味 Buttery2,32,3-戊二酮戊二酮2,3pentanedione美拉德、酵母代谢美拉德、酵母代谢Maillard,yeast metabolism900黄油味、奶

8、酪味黄油味、奶酪味 Buttery,cheesy乙醛乙醛Acetaldehyde正己醇的氧化正己醇的氧化Oxidation of HA1,114 25,000青苹果味青苹果味 Green Apple2 2-甲基丙醛甲基丙醛2-methylpropanalStrecker降解反应降解反应、正己醇的氧化正己醇的氧化Strecker,Oxidation of HA86木头味、水果味木头味、水果味Grainy,Fruity3 3-甲基丁醛甲基丁醛3-methylbutanalStrecker降解反应降解反应、正己醇的氧化正己醇的氧化Strecker,Oxidation of HA56 600麦芽味、樱

9、桃味、杏仁味麦芽味、樱桃味、杏仁味Malty,Cherry,Almond苯乙醛苯乙醛Phenyl acetaldehydeStrecker降解反应降解反应、正己醇的氧化正己醇的氧化Strecker,Oxidation of HA105 600风信子味、花香、玫瑰味风信子味、花香、玫瑰味Hyacinth,Flowery,Roses苯甲醛苯甲醛BenzaldehydeStrecker降解反应降解反应Strecker515 2,000杏仁味、樱桃核味杏仁味、樱桃核味Almond,Cherry Stone甲硫基丙醛甲硫基丙醛MethionalStrecker降解反应降解反应Strecker4.2煮土豆

10、、麦汁味煮土豆、麦汁味Cooked Potato,Worty反反-2 2-壬烯醛壬烯醛Trans-2-nonenal脂肪酸的氧化脂肪酸的氧化Fatty Acid Oxidation0,03 0,11纸板味纸板味Cardboard,Papery2 2-甲基丁酸甲甲基丁酸甲Ethyl-2Methylbutyrate自溶、酒花氧化自溶、酒花氧化Autolysis,Hop Oxidation7 27水果味、糖果味水果味、糖果味Fruity,Sweet,Candy3 3-甲基丁酸乙酯甲基丁酸乙酯Ethyl-3Methylbutyrate自溶、酒花氧化自溶、酒花氧化Autolysis,Hop Oxidat

11、ion18 91水果味、糖果味水果味、糖果味Fruity,Sweet,CandyClick to Add TitleClick to add textTime Conversion of aldehydes into less flavor active alcohols (Saison et al.2011)Scavenging of residual oxygen(Ahrens et al.2018)Production of sulfite(Chen et al.2011)AntioxidantTraps carbonyls in non-volatile adducts TimeExp

12、loiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add text时间时间Time 醛转化为风味较差的醇类醛转化为风味较差的醇类Conversion of aldehydes into less flavor active alcohols (Saison et al.2011)排除残留的氧气排除残留的氧气Scavenging of residual oxygen(Ahrens et al.2018)亚硫酸盐的产生亚硫酸盐的产生Production of sulfite (Chen et al.2011)抗氧化剂抗氧

13、化剂Antioxidant在在不不挥发性加合物中捕获羰基挥发性加合物中捕获羰基化合物化合物Traps carbonyls in non-volatile adducts 时间时间Time开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add textSaison et al.2011Exploiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add textSaison et al.201

14、1开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging表表1 鲜啤酒和相应的老化啤酒鲜啤酒和相应的老化啤酒a中几种不同的老化化合物的浓度（中几种不同的老化化合物的浓度（ppb）乙醛乙醛阈值阈值鲜啤酒鲜啤酒老化啤酒老化啤酒化合物化合物反反-2 2-壬烯醛壬烯醛反反-2 2，4 4-癸二烯醛癸二烯醛2 2-甲基丙醛甲基丙醛2 2-甲基丁醛甲基丁醛3 3-甲基丁醛甲基丁醛苯乙醛苯乙醛甲硫基丙醛甲硫基丙醛糠醛糠醛5 5-羟甲基糠醛羟甲基糠醛乙酰基呋喃乙酰基呋喃双乙酰双乙酰2 2-乙基糠基醚乙基糠基醚-大马酮大马酮乙酸异戊酯乙酸

15、异戊酯a 在在20环境下贮存环境下贮存6个月形成老化啤酒（不进行其它的老化操作），另外加入个月形成老化啤酒（不进行其它的老化操作），另外加入TFDS08和和BFDS02酵母，接酵母，接种量为种量为1106个细胞个细胞/mL，经过二次发酵后，加入相同的酵母菌株，经过二次发酵后，加入相同的酵母菌株RF TFDS08和和RF BFDS02。Click to Add TitleClick to add textSaison et al.2011Exploiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add textSaiso

16、n et al.2011开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging3-甲基丁醛甲基丁醛糠醛糠醛苯乙醛苯乙醛2-甲基丙醛甲基丙醛酵母细胞酵母细胞/mL老化老化老化老化100，0000100，0000老化老化老化老化100，0000100，0000Click to Add TitleClick to add textSaison et al.2011Exploiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add textSaison e

17、t al.2011开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging图图1：拉格啤酒：拉格啤酒40环境下老化处理环境下老化处理3周，随后加入不同数量的蔗糖（周，随后加入不同数量的蔗糖（0、1、2、3和和5g分别对应分别对应S0、S1、S2、S3和和S5）以及接种）以及接种1106个个TFDS08酵母细胞酵母细胞/mL，在，在20下二次发酵三周的感官结果。品尝者的平均分数显示在下二次发酵三周的感官结果。品尝者的平均分数显示在y轴上。轴上。纸板味纸板味溶剂味溶剂味茶藨味茶藨味马德拉酒味马德拉酒味硫磺味硫磺味总分总分老化强

18、度老化强度老化老化美拉德美拉德老化老化Click to Add TitleClick to add textSaison et al.2011Exploiting Yeast to Slow Down Beer AgingClick to Add TitleClick to add textSaison et al.2011开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging图图1：拉格啤酒：拉格啤酒40环境下老化处理环境下老化处理3周，随后加入不同数量的蔗糖（周，随后加入不同数量的蔗糖（0、1、2、3和和5g分别对应

19、分别对应S0、S1、S2、S3和和S5）以及接种）以及接种1106个个TFDS08酵母细胞酵母细胞/mL，在，在20下二次发酵三周的感官结果。品尝者的平均分数显示在下二次发酵三周的感官结果。品尝者的平均分数显示在y轴上。轴上。纸板味纸板味溶剂味溶剂味茶藨味茶藨味马德拉酒味马德拉酒味硫磺味硫磺味总分总分老化强度老化强度老化老化美拉德美拉德老化老化Click to Add TitleClick to add textExploiting Yeast to Slow Down Beer AgingSaison et al.2011Click to Add TitleClick to add text

20、Saison et al.2011开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging纸板味纸板味溶剂味溶剂味溶剂味溶剂味纸板味纸板味马德拉酒味马德拉酒味马德拉酒味马德拉酒味硫磺味硫磺味硫磺味硫磺味美拉德美拉德美拉德美拉德茶藨味茶藨味茶藨味茶藨味总分总分 老化强度老化强度总分总分 老化强度老化强度老化老化老化老化图图2 鲜拉格啤酒（初始）以及同种啤酒在鲜拉格啤酒（初始）以及同种啤酒在20下不加酵母老化下不加酵母老化6个月，经过二次发酵个月，经过二次发酵（RF）后，接种后，接种1106个细胞个细胞/mL的的BFDS02（

21、下面（下面酵母）或酵母）或TFDS08（上面酵母）的感官结果。（上面酵母）的感官结果。品尝者的平均分数显示在品尝者的平均分数显示在y轴上。轴上。初始初始初始初始老化老化老化老化Click to Add TitleClick to add textExploiting Yeast to Slow Down Beer AgingSaison et al.2011Click to Add TitleClick to add textSaison et al.2011开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging纸板味纸

22、板味溶剂味溶剂味溶剂味溶剂味纸板味纸板味马德拉酒味马德拉酒味马德拉酒味马德拉酒味硫磺味硫磺味硫磺味硫磺味美拉德美拉德美拉德美拉德茶藨味茶藨味茶藨味茶藨味总分总分 老化强度老化强度总分总分 老化强度老化强度老化老化老化老化图图2 鲜拉格啤酒（初始）以及同种啤酒在鲜拉格啤酒（初始）以及同种啤酒在20下不加酵母老化下不加酵母老化6个月，经过二次发酵个月，经过二次发酵（RF）后，接种后，接种1106个细胞个细胞/mL的的BFDS02（下面（下面酵母）或酵母）或TFDS08（上面酵母）的感官结果。（上面酵母）的感官结果。品尝者的平均分数显示在品尝者的平均分数显示在y轴上。轴上。初始初始初始初始老化老化老

23、化老化Click to Add TitleClick to add textSugarEtOH+CO2Low pHTemperatureNutrient ScarcityEthanol stressCO2PressureHarsh Conditions make Survival ChallengingClick to Add TitleClick to add textSugarEtOH+CO2低低pHLow pH温度温度Temperature营养不足营养不足Nutrient Scarcity乙醇压力乙醇压力Ethanol stressCO2压力压力CO2Pressure恶劣的环境使生存成为

24、挑战恶劣的环境使生存成为挑战Harsh Conditions make Survival Challenging糖糖乙醇乙醇+CO2Click to Add TitleClick to add textExploiting Yeast to Slow Down Beer AgingDekoninck et al.2013Click to Add TitleClick to add textDekoninck et al.2013开发酵母用于减缓啤酒老化开发酵母用于减缓啤酒老化Exploiting Yeast to Slow Down Beer Aging活力（活力（%）活力（活力（%）时间（天

25、）时间（天）时间（天）时间（天）图图3 接种酵母接种酵母TD04（A）和）和TD05（B）的啤酒二次发酵过程中）的啤酒二次发酵过程中酵酵母活力母活力（%）随时间的变化曲线。啤酒类型：随时间的变化曲线。啤酒类型：=啤酒啤酒A；=啤啤酒酒B；=啤酒啤酒C；=啤酒啤酒D；=啤酒啤酒E。表表1 五种参考啤酒最初的指标特征五种参考啤酒最初的指标特征酒精（酒精（%，v/v）啤酒啤酒A 啤酒啤酒B 啤酒啤酒C 啤酒啤酒D 啤酒啤酒EClick to Add TitleClick to add textContentsBROUWERIJ DUVEL MOORTGATBROUWERIJ LIEFMANSBROU

26、WERIJ DE KONINCKBRASSERIE DACHOUFFEBERNARD BREWERYBREWERY OMMEGANGBOULEVARD BREWING COMPANYFIRESTONE WALKER BREWING COMPANYBROUWERIJ t IJJARR KOMBUCHABIRRIFICIO DEL DUCATOGlobalizationTotal Annual Volume 2.2 Million HectolitersClick to Add TitleClick to add textContentsBROUWERIJ DUVEL MOORTGATBROUWE

27、RIJ LIEFMANSBROUWERIJ DE KONINCKBRASSERIE DACHOUFFEBERNARD BREWERYBREWERY OMMEGANGBOULEVARD BREWING COMPANYFIRESTONE WALKER BREWING COMPANYBROUWERIJ t IJJARR KOMBUCHABIRRIFICIO DEL DUCATO全球化全球化Globalization年度总产量年度总产量2.2亿升亿升Total Annual Volume 2.2 Million HectolitersClick to Add TitleClick to add tex

28、tSugarEtOH+CO2Low pHTemperatureNutrient ScarcityEthanol stressCO2PressureHarsh Conditions make Survival ChallengingGoal:Discover Long-Living YeastClick to Add TitleClick to add textSugarEtOH+CO2恶劣的条件使酵母生存充满挑战恶劣的条件使酵母生存充满挑战Harsh Conditions make Survival Challenging营养不足营养不足Nutrient Scarcity乙醇压力乙醇压力Eth

29、anol stress温度温度Temperature低低pHLow pHCO2压力压力CO2Pressure糖糖乙醇乙醇+CO2目标：发现长寿酵母目标：发现长寿酵母Goal:Discover Long-Living YeastClick to Add TitleClick to add textFlocculationSugar utilization Temperature toleranceEthanol toleranceFlavor NeutralScreening a Diverse PopulationGenetic Screening of 170 Diverse Strains

30、Click to Add TitleClick to add text絮凝性絮凝性Flocculation糖利用率糖利用率Sugar utilization 耐温性耐温性Temperature tolerance乙醇耐受性乙醇耐受性Ethanol tolerance风味中性风味中性Flavor Neutral筛选不同的种群筛选不同的种群Screening a Diverse Population170170个不同菌株的遗传筛选个不同菌株的遗传筛选Genetic Screening of 170 Diverse StrainsClick to Add TitleClick to add text

31、FlocculationSugar utilization Temperature toleranceEthanol toleranceFlavor NeutralScreening a Diverse PopulationGenetic Screening of 170 Diverse Strains10 ml Green Duvel+1,5%EtOH+0.2P glucose+2x106cells/ml Click to Add TitleClick to add text絮凝性絮凝性Flocculation糖利用率糖利用率Sugar utilization 耐温性耐温性Temperatu

32、re tolerance乙醇耐受性乙醇耐受性Ethanol tolerance风味中性风味中性Flavor Neutral筛选不同的种群筛选不同的种群Screening a Diverse Population170170个不同菌株的遗传筛选个不同菌株的遗传筛选Genetic Screening of 170 Diverse Strains10mL嫩啤酒嫩啤酒10 ml Green Duvel+1.5%乙醇乙醇+1,5%EtOH+0.2P蔗糖蔗糖+0.2P glucose+2x106个细胞个细胞/ml+2x106cells/mlClick to Add TitleClick to add te

33、xtFlocculationSugar utilization Temperature toleranceEthanol toleranceFlavor NeutralScreening a Diverse PopulationGenetic Screening of 170 Diverse Strains10 ml Green Duvel+1,5%EtOH+0.2P glucose+2x106cells/ml Methylene Violet StainingTime-Lapse MicroscopyMetabolic ActivityGrowth50 daysat 30CClick to

34、Add TitleClick to add text絮凝性絮凝性Flocculation糖利用率糖利用率Sugar utilization 耐温性耐温性Temperature tolerance乙醇耐受性乙醇耐受性Ethanol tolerance风味中性风味中性Flavor Neutral筛选不同的种群筛选不同的种群Screening a Diverse Population170170个不同菌株的遗传筛选个不同菌株的遗传筛选Genetic Screening of 170 Diverse Strains10mL嫩啤酒嫩啤酒10 ml Green Duvel+1.5%乙醇乙醇+1,5%EtO

35、H+0.2P蔗糖蔗糖+0.2P glucose+2x106个细胞个细胞/ml+2x106cells/ml50 daysat 30C新陈代谢活动新陈代谢活动Metabolic Activity亚甲基紫染色亚甲基紫染色Methylene Violet Staining时间间隔显微镜时间间隔显微镜Time-Lapse Microscopy生长生长GrowthClick to Add TitleClick to add textFlocculationSugar utilization Temperature toleranceEthanol toleranceFlavor NeutralScreen

36、ing a Diverse PopulationGenetic Screening of 176Diverse Strains10 ml Green Duvel+1,5%EtOH+0.2P glucose+2x106cells/ml Methylene Violet StainingTime-Lapse MicroscopyMetabolic ActivityGrowth50 daysat 30Cn=1762 replicatesClick to Add TitleClick to add text絮凝性絮凝性Flocculation糖利用率糖利用率Sugar utilization 耐温性耐

37、温性Temperature tolerance乙醇耐受性乙醇耐受性Ethanol tolerance风味中性风味中性Flavor Neutral筛选不同的种群筛选不同的种群Screening a Diverse Population170170个不同菌株的遗传筛选个不同菌株的遗传筛选Genetic Screening of 170 Diverse Strains10mL嫩啤酒嫩啤酒10 ml Green Duvel+1.5%乙醇乙醇+1,5%EtOH+0.2P蔗糖蔗糖+0.2P glucose+2x106个细胞个细胞/ml+2x106cells/ml50 daysat 30C新陈代谢活动新陈代

38、谢活动Metabolic Activity亚甲基紫染色亚甲基紫染色Methylene Violet Staining时间间隔显微镜时间间隔显微镜Time-Lapse Microscopy生长生长Growthn=176两次重复两次重复2 replicates亚甲基紫染色确定活力亚甲基紫染色确定活力（部分细胞）（部分细胞）显微镜确定活力显微镜确定活力（部分细胞）（部分细胞）Click to Add TitleClick to add textViability Evolution during RefermentationClick to Add TitleClick to add text二次发

39、酵过程中活力的变化二次发酵过程中活力的变化Viability Evolution during Refermentation0天天1周周2周周4周周密度密度密度密度密度密度密度密度生长率（生长率（AU）生长率（生长率（AU）Click to Add TitleClick to add textGrowth RatesViableDeadIndividual viabilitiesGrowth Rates:Distinguish“Live”and“Dead”CellsClick to Add TitleClick to add text生长率生长率Growth RatesViableDead单个

40、细胞活力单个细胞活力Individual viabilities生长率：区分生长率：区分“活活”和和“死细胞死细胞”Growth Rates:Distinguish“Live”and“Dead”Cells死细胞死细胞活细胞活细胞Click to Add TitleClick to add textR=0,64 p 2e-16A few survived showed considerable promiseClick to Add TitleClick to add textR=0,64 p 2e-16一些幸存一些幸存的酵母细胞的酵母细胞显示出可观的希望显示出可观的希望A few surviv

41、ed showed considerable promise通过显微镜观察活力通过显微镜观察活力（部分细胞）（部分细胞）亚甲基紫染色确定活力（部分细胞）亚甲基紫染色确定活力（部分细胞）Click to Add TitleClick to add textR=0,64 p 2e-16A few survived showed considerable promiseClick to Add TitleClick to add textR=0,64 p 2e-16A few survived showed considerable promise通过显微镜观察活力通过显微镜观察活力（部分细胞）（部

42、分细胞）一些幸存一些幸存的酵母细胞的酵母细胞显示出可观的希望显示出可观的希望A few survived showed considerable promise亚甲基紫染色确定活力（部分细胞）亚甲基紫染色确定活力（部分细胞）Click to Add TitleClick to add textT im e of m easurin g(days)T em p eratu re(C)010455366819311407243518Exploiting Natural Diversity to Stop Beer AgingRefermentationCold MaturationTransit

43、Simulation30 strains(Biological Triplicate)Endpoint Only Superior Survival YeastsClick to Add TitleClick to add textT im e of m easurin g(days)T em p eratu re(C)010455366819311407243518利用自然多样性阻止啤酒老化利用自然多样性阻止啤酒老化Exploiting Natural Diversity to Stop Beer Aging二次发酵二次发酵Refermentation低温成熟低温成熟Cold Maturat

44、ion运输模拟运输模拟Transit Simulation3030个菌株（三次生物重复）个菌株（三次生物重复）仅端点仅端点幸存的优越酵母幸存的优越酵母30 strains(Biological Triplicate)Endpoint Only Superior Survival YeastsClick to Add TitleClick to add textExploiting Natural Diversity to Stop Beer AgingCFU5%Viable0.5%Viable0.1%ViableClick to Add TitleClick to add textCFU5%V

45、iable0.5%Viable0.1%Viable利用自然多样性阻止啤酒老化利用自然多样性阻止啤酒老化Exploiting Natural Diversity to Stop Beer Aging活力（活力（%）活力（活力（%）时间（天）时间（天）时间（天）时间（天）菌株菌株活力活力0.1%活力活力0.5%活力活力5%Click to Add TitleClick to add textBeing analyzed.SupernatantFuture ResearchPelletClick to Add TitleClick to add textBeing analyzed.上清液上清液Su

46、pernatant未来的研究未来的研究Future Research菌体菌体PelletClick to Add TitleClick to add textKey Take-Away Messages Flavor stability is impacted by a myriad of factors,including time.Globalization has amplified the need for brewers to enhance product freshness in order to compete in foreign markets.Refermentation

47、 and/or yeast can be exploited to reduce the perception of“aging compounds”in beer.Conventional strains have a limited lifespan once packaged.However,our lab has identified several strains that maintain viability for an extended period under harsh storage conditions.Click to Add TitleClick to add te

48、xt要点要点Key Take-Away Messages风味稳定性受到诸多风味稳定性受到诸多因素的影响因素的影响，包括时间。，包括时间。Flavor stability is impacted by a myriad of factors,including time.全球化加剧了全球化加剧了酿酒师酿酒师提高提高啤酒啤酒新鲜度新鲜度的需求，的需求，以便以便能在能在国外市场国外市场有竞争力有竞争力。Globalization has amplified the need for brewers to enhance product freshness in order to compete in

49、 foreign markets.利用二次发酵以及利用二次发酵以及/或酵母减少啤酒中对或酵母减少啤酒中对“老化化合物老化化合物”的感知。的感知。Refermentation and/or yeast can be exploited to reduce the perception of“aging compounds”in beer.传统传统菌株包装后使用寿命有限菌株包装后使用寿命有限。但是，我们的实验室已经确定了但是，我们的实验室已经确定了几种在恶劣的几种在恶劣的贮存贮存条件下条件下可以可以长期保持活力的菌株。长期保持活力的菌株。Conventional strains have a limited lifespan once packaged.However,our lab has identified several strains that maintain viability for an extended period under harsh storage conditions.