Pub Date : 2022-09-02DOI: 10.1080/03610470.2022.2110819
Campbell P. Morrissy, Margaret A. Halstead, Michael Féchir, D. Carrijo, S. Fisk, Vern Johnson, H. Bettenhausen, T. Shellhammer, P. Hayes
Abstract Understanding the role barley variety plays in the overall flavor profile of beer is an area of research of interest to barley breeders, maltsters, and brewers. Here we build on previous research on the effect of barley variety on beer flavor by focusing on commercial-type malts and beers. A selection of three winter-habit, elite malting lines – two released varieties and one experimental – were grown in three locations across Oregon and California and harvested in summer 2020. Each was malted to the specifications of Pilsner-style malt. Beers were produced to mimic offerings of the industry partner and utilized a small portion of specialty malt and higher hopping rates than previous work. All beers underwent descriptive sensory analysis and Projective Mapping (Napping®) to characterize and determine the magnitude of separation between samples. Malting and brewing performance differed among the nine entries, but sensory outcomes showed only minor separation and few significant differences in the descriptive analysis. The results here showed that there is correlation between malt modification and sensory outcomes and ultimately confirmed that barley variety and growing location contributes to beer flavor. However, the overall contributions are nuanced, particularly in commercial-ty3pe malts and beers.
{"title":"Barley Variety and Growing Location Provide Nuanced Contributions to Beer Flavor Using Elite Germplasm in Commercial-Type Malts and Beers","authors":"Campbell P. Morrissy, Margaret A. Halstead, Michael Féchir, D. Carrijo, S. Fisk, Vern Johnson, H. Bettenhausen, T. Shellhammer, P. Hayes","doi":"10.1080/03610470.2022.2110819","DOIUrl":"https://doi.org/10.1080/03610470.2022.2110819","url":null,"abstract":"Abstract Understanding the role barley variety plays in the overall flavor profile of beer is an area of research of interest to barley breeders, maltsters, and brewers. Here we build on previous research on the effect of barley variety on beer flavor by focusing on commercial-type malts and beers. A selection of three winter-habit, elite malting lines – two released varieties and one experimental – were grown in three locations across Oregon and California and harvested in summer 2020. Each was malted to the specifications of Pilsner-style malt. Beers were produced to mimic offerings of the industry partner and utilized a small portion of specialty malt and higher hopping rates than previous work. All beers underwent descriptive sensory analysis and Projective Mapping (Napping®) to characterize and determine the magnitude of separation between samples. Malting and brewing performance differed among the nine entries, but sensory outcomes showed only minor separation and few significant differences in the descriptive analysis. The results here showed that there is correlation between malt modification and sensory outcomes and ultimately confirmed that barley variety and growing location contributes to beer flavor. However, the overall contributions are nuanced, particularly in commercial-ty3pe malts and beers.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"404 - 415"},"PeriodicalIF":2.0,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44576051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-30DOI: 10.1080/03610470.2022.2109380
Alexandre Dusart, J. Ryckaert, S. Collin
Abstract Red and brown Flemish sour beers form a distinct class of Belgian beers obtained by mixed (yeast/lactic bacteria) microbial fermentation and often resulting from blending a 1-to-2-year-old beer with a younger one to obtain a balance between acidic character and sweetness. A detailed composition in volatiles (phenols, lactones, esters, alcohols, acids, …) of three beers representative of the red and brown subcategories is presented. GC data were obtained after different extraction procedures, including solvent-assisted flavor evaporation (SAFE) and headspace. The first results showed the influence of Brettanomyces yeast on the phenol and ester contents. An efficient Brettanomyces activity in the red sour beers (especially in Rodenbach Vintage) was observed, favored by long maturation in wooden casks. This was organoleptically perceived by the horsey flavors brought by 4-ethylguaiacol and 4-ethylphenol, and the solvent-like ethyl acetate through esterase activity. The brown Flemish sour beer (produced in stainless steel fermenters) showed significantly more unreduced 4-vinylguaiacol and 4-vinylphenol, although traces of 4-ethylguaiacol and 4-ethylphenol were also detected (most probably here issued from torrefied malts, as suggested by the opposite substituted phenol/guaiacol ratio).
{"title":"Comparative Investigation of Flavors in Red and Brown Flemish Beers: Key-Role of Brettanomyces and Torrefied Malts in Ethylphenols Occurrence","authors":"Alexandre Dusart, J. Ryckaert, S. Collin","doi":"10.1080/03610470.2022.2109380","DOIUrl":"https://doi.org/10.1080/03610470.2022.2109380","url":null,"abstract":"Abstract Red and brown Flemish sour beers form a distinct class of Belgian beers obtained by mixed (yeast/lactic bacteria) microbial fermentation and often resulting from blending a 1-to-2-year-old beer with a younger one to obtain a balance between acidic character and sweetness. A detailed composition in volatiles (phenols, lactones, esters, alcohols, acids, …) of three beers representative of the red and brown subcategories is presented. GC data were obtained after different extraction procedures, including solvent-assisted flavor evaporation (SAFE) and headspace. The first results showed the influence of Brettanomyces yeast on the phenol and ester contents. An efficient Brettanomyces activity in the red sour beers (especially in Rodenbach Vintage) was observed, favored by long maturation in wooden casks. This was organoleptically perceived by the horsey flavors brought by 4-ethylguaiacol and 4-ethylphenol, and the solvent-like ethyl acetate through esterase activity. The brown Flemish sour beer (produced in stainless steel fermenters) showed significantly more unreduced 4-vinylguaiacol and 4-vinylphenol, although traces of 4-ethylguaiacol and 4-ethylphenol were also detected (most probably here issued from torrefied malts, as suggested by the opposite substituted phenol/guaiacol ratio).","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"357 - 365"},"PeriodicalIF":2.0,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43603230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-29DOI: 10.1080/03610470.2022.2104060
M. Vinje, J. Walling, C. Henson, S. H. Duke
Abstract Disproportionating enzyme (D-enzyme) is a 4-α-glucanotransferase (EC 2.4.1.25) that disproportionates α-glucans and maltooligosaccharides and preferentially disproportionates maltotriose into maltopentaose and glucose. Maltotriose is a maltooligosaccharide that accumulates in barley malt and wort without being digested further by starch degrading enzymes. Furthermore, not all brewer’s yeast strains can ferment maltotriose. This research was undertaken to determine if D-enzyme is expressed in developing and/or malting barley grains and thus providing evidence of an inherent enzymatic mechanism capable of disproportionating maltotriose into maltopentaose that can be further degraded into fermentable sugars by amylolytic enzymes such as β-amylase. A partial genomic sequence of barley disproportionating enzyme 1 (DPE1) was obtained that was comprised of 16 exons and 15 introns totaling 4680 bp. The 5’ region of the DPE1 gene was recalcitrant to Sanger sequencing owing to its localization in a highly repetitive region of the barley genome. The DPE1 gene is expressed during grain development and the protein stored in the mature grain. Additionally, the DPE1 gene is de novo expressed during malting in both a 2- and 6-row malting cultivar with significant variation observed amongst 13 elite malting cultivars representing spring and winter growth habits. During grain development, DPE1 mRNA levels peak at 17 days after anthesis, which coincides with a large increase in proteins that react to anti-DPE1 polyclonal antibodies. These proteins appear as a doublet on immunoblots during initial stages of malting and as a singlet as malting progresses indicating proteolytic processing (e.g., transit peptide removal) or differential isoform/splice variant expression.
{"title":"Temporal Expression Analysis of Barley Disproportionating Enzyme 1 (DPE1) during Grain Development and Malting","authors":"M. Vinje, J. Walling, C. Henson, S. H. Duke","doi":"10.1080/03610470.2022.2104060","DOIUrl":"https://doi.org/10.1080/03610470.2022.2104060","url":null,"abstract":"Abstract Disproportionating enzyme (D-enzyme) is a 4-α-glucanotransferase (EC 2.4.1.25) that disproportionates α-glucans and maltooligosaccharides and preferentially disproportionates maltotriose into maltopentaose and glucose. Maltotriose is a maltooligosaccharide that accumulates in barley malt and wort without being digested further by starch degrading enzymes. Furthermore, not all brewer’s yeast strains can ferment maltotriose. This research was undertaken to determine if D-enzyme is expressed in developing and/or malting barley grains and thus providing evidence of an inherent enzymatic mechanism capable of disproportionating maltotriose into maltopentaose that can be further degraded into fermentable sugars by amylolytic enzymes such as β-amylase. A partial genomic sequence of barley disproportionating enzyme 1 (DPE1) was obtained that was comprised of 16 exons and 15 introns totaling 4680 bp. The 5’ region of the DPE1 gene was recalcitrant to Sanger sequencing owing to its localization in a highly repetitive region of the barley genome. The DPE1 gene is expressed during grain development and the protein stored in the mature grain. Additionally, the DPE1 gene is de novo expressed during malting in both a 2- and 6-row malting cultivar with significant variation observed amongst 13 elite malting cultivars representing spring and winter growth habits. During grain development, DPE1 mRNA levels peak at 17 days after anthesis, which coincides with a large increase in proteins that react to anti-DPE1 polyclonal antibodies. These proteins appear as a doublet on immunoblots during initial stages of malting and as a singlet as malting progresses indicating proteolytic processing (e.g., transit peptide removal) or differential isoform/splice variant expression.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"396 - 403"},"PeriodicalIF":2.0,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48349285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-22DOI: 10.1080/03610470.2022.2110645
M. Cottrell
Abstract Identifying beer spoilage microbes is readily accomplished using PCR analyses targeting specific types of microbes, but the general classification of wild yeast versus brewing yeast using cultivation independent molecular methods has remained challenging. The approach presented in this study utilized genetic fingerprint matching to determine if an unknown yeast isolate matches the fingerprint of catalogued brewing yeast strains. Interdelta Next Generation Sequencing (NGS) fingerprints were produced using PCR amplification of delta elements, also known as long terminal repeat sequences of transposons of yeast. Fingerprints identifying different yeast strains were generated by processing reads produced by NGS of the interdelta PCR amplicons using open source software. The interdelta NGS fingerprint comprises DNA sequences that can be recorded, compared, and utilized as a fixed reference for yeast strain identification. Interdelta NGS fingerprints were shown to be reproducible and capable of distinguishing between strains of brewing yeast and wild yeast. Experimental yeast contamination demonstrated the utility of the approach for identifying in-house brewing yeast cross contamination versus foreign wild yeast contamination.
利用针对特定类型微生物的PCR分析很容易完成啤酒腐败微生物的鉴定，但利用培养独立的分子方法对野生酵母和酿造酵母进行一般分类仍然具有挑战性。本研究中提出的方法利用遗传指纹匹配来确定未知酵母菌分离物是否与已编目的酿造酵母菌菌株的指纹匹配。利用酵母转座子长末端重复序列(delta element)的PCR扩增，获得了delta Next Generation Sequencing (NGS)指纹图谱。利用开源软件对三角间PCR扩增子NGS产生的reads进行处理，生成识别不同酵母菌株的指纹图谱。三角洲间NGS指纹图谱包括可记录、比较和用作酵母菌株鉴定的固定参考的DNA序列。三角间NGS指纹图谱具有可重复性，能够区分酿酒酵母和野生酵母菌株。实验酵母污染证明了该方法在鉴别内部酿造酵母交叉污染和外来野生酵母污染方面的实用性。
{"title":"Fingerprinting Saccharomyces cerevisiae Strains Using Next Generation Sequencing of PCR Amplicons Generated from Delta Elements","authors":"M. Cottrell","doi":"10.1080/03610470.2022.2110645","DOIUrl":"https://doi.org/10.1080/03610470.2022.2110645","url":null,"abstract":"Abstract Identifying beer spoilage microbes is readily accomplished using PCR analyses targeting specific types of microbes, but the general classification of wild yeast versus brewing yeast using cultivation independent molecular methods has remained challenging. The approach presented in this study utilized genetic fingerprint matching to determine if an unknown yeast isolate matches the fingerprint of catalogued brewing yeast strains. Interdelta Next Generation Sequencing (NGS) fingerprints were produced using PCR amplification of delta elements, also known as long terminal repeat sequences of transposons of yeast. Fingerprints identifying different yeast strains were generated by processing reads produced by NGS of the interdelta PCR amplicons using open source software. The interdelta NGS fingerprint comprises DNA sequences that can be recorded, compared, and utilized as a fixed reference for yeast strain identification. Interdelta NGS fingerprints were shown to be reproducible and capable of distinguishing between strains of brewing yeast and wild yeast. Experimental yeast contamination demonstrated the utility of the approach for identifying in-house brewing yeast cross contamination versus foreign wild yeast contamination.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"374 - 382"},"PeriodicalIF":2.0,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42913885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-02DOI: 10.1080/03610470.2022.2093091
Nobuyuki Hayashi, Ritsuko Arai, Toshiko Minato, Y. Fujita
Abstract Growth tests in beers supplemented with specific chemical substances were conducted to investigate the growth control method of beer-spoilage bacteria. Lactobacillus brevis and Pectinatus frisingensis were inoculated into beers in which the pH was set and chemical substances had been added to form a matrix. Supplementation of the beer with hop bitter compounds (iso-α-acids, α-acids, or SO2), had an inhibitory effect on the growth of the tested strains in beer. Furthermore, the growth inhibiting compounds had a synergistic effect when used simultaneously. Two-way repeated measures analysis of variance showed that the interaction effects of combinations of iso-α-acids and α-acids in addition to α-acids and SO2 on the growth of L. brevis and P. frisingensis in beer were highly significant. To verify the contribution degree of pH, iso-α-acids, α-acids, and SO2 on the growth of L. brevis and P. frisingensis, growth test results using a combination of these factors set at different levels were subject to stepwise regression. The contributions of undissociated α-acids, undissociated SO2, and multiplications of undissociated α-acids and undissociated SO2 were especially high in the control of L. brevis growth. The contributions of pH, undissociated SO2, and multiplications of pH and undissociated iso-α-acids were especially high in the control of P. frisingensis growth. The difference in the contributions of antibacterial compounds between L. brevis and P. frisingensis may be due to the difference in the cell wall/membrane structure. Such factorial analysis may be useful for parameter setting in future product designs and process adjustments.
{"title":"Factorial Analysis of Variance of the Inhibiting Effects of Iso-Alpha Acids, Alpha Acids, and Sulfur Dioxide on the Growth of Beer-Spoilage Bacteria in Beer","authors":"Nobuyuki Hayashi, Ritsuko Arai, Toshiko Minato, Y. Fujita","doi":"10.1080/03610470.2022.2093091","DOIUrl":"https://doi.org/10.1080/03610470.2022.2093091","url":null,"abstract":"Abstract Growth tests in beers supplemented with specific chemical substances were conducted to investigate the growth control method of beer-spoilage bacteria. Lactobacillus brevis and Pectinatus frisingensis were inoculated into beers in which the pH was set and chemical substances had been added to form a matrix. Supplementation of the beer with hop bitter compounds (iso-α-acids, α-acids, or SO2), had an inhibitory effect on the growth of the tested strains in beer. Furthermore, the growth inhibiting compounds had a synergistic effect when used simultaneously. Two-way repeated measures analysis of variance showed that the interaction effects of combinations of iso-α-acids and α-acids in addition to α-acids and SO2 on the growth of L. brevis and P. frisingensis in beer were highly significant. To verify the contribution degree of pH, iso-α-acids, α-acids, and SO2 on the growth of L. brevis and P. frisingensis, growth test results using a combination of these factors set at different levels were subject to stepwise regression. The contributions of undissociated α-acids, undissociated SO2, and multiplications of undissociated α-acids and undissociated SO2 were especially high in the control of L. brevis growth. The contributions of pH, undissociated SO2, and multiplications of pH and undissociated iso-α-acids were especially high in the control of P. frisingensis growth. The difference in the contributions of antibacterial compounds between L. brevis and P. frisingensis may be due to the difference in the cell wall/membrane structure. Such factorial analysis may be useful for parameter setting in future product designs and process adjustments.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"424 - 434"},"PeriodicalIF":2.0,"publicationDate":"2022-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44159814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-13DOI: 10.1080/03610470.2022.2089010
Michael Féchir, Garrett Weaver, Curtis Roy, T. Shellhammer
Abstract The impact of the growing environment on the aroma of agricultural products such as wine, coffee, or tea has been investigated in detail, leading to the concept of regional identity; however, there have been only limited studies examining regional variation in hops. A systematic investigation of Cascade and Mosaic® hops from the 2020 harvest year grown at 39 different locations in Oregon and Washington was performed using chemical/instrumental and human sensory analyses, which revealed significant between-state and within-state differences for both varieties, suggesting substantial regional and subregional identity effects. A subset of 14 hop samples was selected to produce standardized single-hop beers (IPA) in pilot scale. Sensory evaluation of the beers revealed similar regional-dependent results as observed for the hops with slightly stronger fruity, citrus, and tropical notes but weaker herbal, grassy, and woody notes in the beers compared to hops, suggesting that the regional identity effect was observable in beer.
{"title":"Exploring the Regional Identity of Cascade and Mosaic® Hops Grown at Different Locations in Oregon and Washington","authors":"Michael Féchir, Garrett Weaver, Curtis Roy, T. Shellhammer","doi":"10.1080/03610470.2022.2089010","DOIUrl":"https://doi.org/10.1080/03610470.2022.2089010","url":null,"abstract":"Abstract The impact of the growing environment on the aroma of agricultural products such as wine, coffee, or tea has been investigated in detail, leading to the concept of regional identity; however, there have been only limited studies examining regional variation in hops. A systematic investigation of Cascade and Mosaic® hops from the 2020 harvest year grown at 39 different locations in Oregon and Washington was performed using chemical/instrumental and human sensory analyses, which revealed significant between-state and within-state differences for both varieties, suggesting substantial regional and subregional identity effects. A subset of 14 hop samples was selected to produce standardized single-hop beers (IPA) in pilot scale. Sensory evaluation of the beers revealed similar regional-dependent results as observed for the hops with slightly stronger fruity, citrus, and tropical notes but weaker herbal, grassy, and woody notes in the beers compared to hops, suggesting that the regional identity effect was observable in beer.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"480 - 492"},"PeriodicalIF":2.0,"publicationDate":"2022-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43040036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-01DOI: 10.1080/03610470.2022.2084327
M. Cottrell
Abstract A search was conducted for the sources of diastatic enzymes driving the over attenuation and continued fermentation of dry hopped beer known as “hop creep”. Microbial cultivation using starch containing media and assays of amylase enzyme activity were used to isolate and identify microbes from pellet hops that are potential sources of amylases associated with but exogenous to hops (Humulus lupulus). Bacteria and fungi associated with pellet hops produced amylases but did not produce hop creep in assays using finished beer and fermenting wort with added microbes. Cannabis sativa flower produced over attenuation of fermenting wort equivalent to that seen with hops. Comparative bioinformatic analysis of the Cannabis sativa proteome and H. lupulus genome revealed the genetic potential of H. lupulus to produce endogenous amylase enzymes. Sequence similarity of amylases annotated in the C. sativa proteome to previously unidentified genes in H. lupulus revealed 13 genes likely encoding amylases. PCR and sequencing confirmed the occurrence of genes that appear to encode α-amylase and β-amylase in the Citra® hop cultivar. Identifying a genetic basis for hop creep contributes knowledge that may lead to new approaches for controlling hop creep produced by endogenous amylases of H. lupulus.
{"title":"A Search for Diastatic Enzymes Endogenous to Humulus lupulus and Produced by Microbes Associated with Pellet Hops Driving “Hop Creep” of Dry Hopped Beer","authors":"M. Cottrell","doi":"10.1080/03610470.2022.2084327","DOIUrl":"https://doi.org/10.1080/03610470.2022.2084327","url":null,"abstract":"Abstract A search was conducted for the sources of diastatic enzymes driving the over attenuation and continued fermentation of dry hopped beer known as “hop creep”. Microbial cultivation using starch containing media and assays of amylase enzyme activity were used to isolate and identify microbes from pellet hops that are potential sources of amylases associated with but exogenous to hops (Humulus lupulus). Bacteria and fungi associated with pellet hops produced amylases but did not produce hop creep in assays using finished beer and fermenting wort with added microbes. Cannabis sativa flower produced over attenuation of fermenting wort equivalent to that seen with hops. Comparative bioinformatic analysis of the Cannabis sativa proteome and H. lupulus genome revealed the genetic potential of H. lupulus to produce endogenous amylase enzymes. Sequence similarity of amylases annotated in the C. sativa proteome to previously unidentified genes in H. lupulus revealed 13 genes likely encoding amylases. PCR and sequencing confirmed the occurrence of genes that appear to encode α-amylase and β-amylase in the Citra® hop cultivar. Identifying a genetic basis for hop creep contributes knowledge that may lead to new approaches for controlling hop creep produced by endogenous amylases of H. lupulus.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"435 - 447"},"PeriodicalIF":2.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49017494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.1080/03610470.2022.2081958
Yunqian Cui, Jingqin Cao, Zimeng Wu, J. Du
Abstract Cropping yeast is prevalent in many commercial breweries due to routine brewing patterns and cost savings. One of the biggest challenges of cropping yeast in wheat beers is the impact of cropping methods on yeast performance and on beer quality and sensory characteristics. The objective of this study was to evaluate the ability of top-fermenting yeasts, when re-pitched to subsequent worts, to reach fermentation objectives and to assess their effects on wheat beer flavors. With the increase in crop numbers of the top-fermenting yeasts, the surface wrinkles on the older cells were deepened as observed using scanning electron microscopy (SEM), and the cell-to-cell adhesion tended to be more pronounced. In comparison to the freshly propagated yeasts, fermentation by older cropped yeasts resulted in significant increases (p < 0.05) in the levels of turbidity (up to 20%), lactic acid (up to 182%), total acids (up to 79.0%), residual sugars (up to 25%), isobutanol (up to 33%), and isoamyl alcohol (up to 24.2%) in the final wheat beers of the current study. Finally, sensory evaluation revealed that the sourness of the final wheat beers was more pronounced with older yeast crops. These results showed that re-pitching with later crops of top-fermentation yeasts was not optimal for the quality of the final wheat beers. Better methods of re-pitching top-fermenting yeasts are suggested to be cropping from the surface of young beer after primary fermentation or directly pitching the fermenting wort for the subsequent brew.
{"title":"The Effects of Harvesting Methods and Crop Numbers of Top-Fermenting Yeasts on the Flavor of Wheat Beer","authors":"Yunqian Cui, Jingqin Cao, Zimeng Wu, J. Du","doi":"10.1080/03610470.2022.2081958","DOIUrl":"https://doi.org/10.1080/03610470.2022.2081958","url":null,"abstract":"Abstract Cropping yeast is prevalent in many commercial breweries due to routine brewing patterns and cost savings. One of the biggest challenges of cropping yeast in wheat beers is the impact of cropping methods on yeast performance and on beer quality and sensory characteristics. The objective of this study was to evaluate the ability of top-fermenting yeasts, when re-pitched to subsequent worts, to reach fermentation objectives and to assess their effects on wheat beer flavors. With the increase in crop numbers of the top-fermenting yeasts, the surface wrinkles on the older cells were deepened as observed using scanning electron microscopy (SEM), and the cell-to-cell adhesion tended to be more pronounced. In comparison to the freshly propagated yeasts, fermentation by older cropped yeasts resulted in significant increases (p < 0.05) in the levels of turbidity (up to 20%), lactic acid (up to 182%), total acids (up to 79.0%), residual sugars (up to 25%), isobutanol (up to 33%), and isoamyl alcohol (up to 24.2%) in the final wheat beers of the current study. Finally, sensory evaluation revealed that the sourness of the final wheat beers was more pronounced with older yeast crops. These results showed that re-pitching with later crops of top-fermentation yeasts was not optimal for the quality of the final wheat beers. Better methods of re-pitching top-fermenting yeasts are suggested to be cropping from the surface of young beer after primary fermentation or directly pitching the fermenting wort for the subsequent brew.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"366 - 373"},"PeriodicalIF":2.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43090793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-23DOI: 10.1080/03610470.2022.2079944
J. Leker, J. Maye
Abstract Hops, Humulus lupulus, contain two major organic acids, humulones, also known as alpha acids, and lupulones, also known as beta acids. These two organic acids are composed of a mixture of three major homologs referred to as co-, n-, and ad-. There are also three minor homologs known as post-, pre- and adpre- however these minor hop acid homologs are found in dry hops at very low concentrations, usually less than 0.2%. Today, we report the discovery of a fourth minor homolog for alpha acids and beta acids found in hops called aceto-.
{"title":"Discovery of Acetohumulone and Acetolupulone a New Hop Alpha Acid and Beta Acid","authors":"J. Leker, J. Maye","doi":"10.1080/03610470.2022.2079944","DOIUrl":"https://doi.org/10.1080/03610470.2022.2079944","url":null,"abstract":"Abstract Hops, Humulus lupulus, contain two major organic acids, humulones, also known as alpha acids, and lupulones, also known as beta acids. These two organic acids are composed of a mixture of three major homologs referred to as co-, n-, and ad-. There are also three minor homologs known as post-, pre- and adpre- however these minor hop acid homologs are found in dry hops at very low concentrations, usually less than 0.2%. Today, we report the discovery of a fourth minor homolog for alpha acids and beta acids found in hops called aceto-.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"276 - 281"},"PeriodicalIF":2.0,"publicationDate":"2022-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44694488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.1080/03610470.2022.2078946
James Bruner, Andrew Marcus, Glen P. Fox
Abstract Hops were traditionally used in brewing for the addition of isomerized alpha acids that balance the sugary wort with bitterness, though modern breweries are dry-hopping to add complex and unique aromas to their beers. An unintended consequence of high amounts of dry-hopping is the phenomenon known as hop creep, causing an increase in alcohol, carbonation, and diacetyl concentrations. The amount of diacetyl in a beer can be directly correlated to yeast health and vitality, controlled by the amount of free amino nitrogen (FAN) available to the yeast. In this study, both diacetyl and amino acid concentrations were measured prior to and 24 h after dry-hopping, at terminal gravity, and at the start of fermentation. These values were compared across twelve yeasts that are commonly used in dry-hopped beer or offer unique characteristics to fermentation. Experimental yeasts BY881, WLP518, K-97, and CK S102 all exhibited diacetyl concentrations below the aroma threshold for beer. The addition of dry-hops added a significant (p < 0.05) increase in FAN content to the fermenting beers, with most of the increases in serine, arginine, glutamate/glutamine, alanine, and glycine. These increases did not parallel the amino acid content measured in the grist or hops, where asparagine/aspartic acid, proline, and glutamate/glutamine were most prominent. Correlations between total FAN content and diacetyl concentration were calculated, as diacetyl is a precursor in the biosynthesis pathway of the amino acids valine and leucine. However, in this experiment, no correlation of amino acid and diacetyl concentration was observed between dry-hopped and traditional fermentations.
{"title":"Changes in Diacetyl and Amino Acid Concentration during the Fermentation of Dry-Hopped Beer: A Look at Twelve Saccharomyces Species and Strains","authors":"James Bruner, Andrew Marcus, Glen P. Fox","doi":"10.1080/03610470.2022.2078946","DOIUrl":"https://doi.org/10.1080/03610470.2022.2078946","url":null,"abstract":"Abstract Hops were traditionally used in brewing for the addition of isomerized alpha acids that balance the sugary wort with bitterness, though modern breweries are dry-hopping to add complex and unique aromas to their beers. An unintended consequence of high amounts of dry-hopping is the phenomenon known as hop creep, causing an increase in alcohol, carbonation, and diacetyl concentrations. The amount of diacetyl in a beer can be directly correlated to yeast health and vitality, controlled by the amount of free amino nitrogen (FAN) available to the yeast. In this study, both diacetyl and amino acid concentrations were measured prior to and 24 h after dry-hopping, at terminal gravity, and at the start of fermentation. These values were compared across twelve yeasts that are commonly used in dry-hopped beer or offer unique characteristics to fermentation. Experimental yeasts BY881, WLP518, K-97, and CK S102 all exhibited diacetyl concentrations below the aroma threshold for beer. The addition of dry-hops added a significant (p < 0.05) increase in FAN content to the fermenting beers, with most of the increases in serine, arginine, glutamate/glutamine, alanine, and glycine. These increases did not parallel the amino acid content measured in the grist or hops, where asparagine/aspartic acid, proline, and glutamate/glutamine were most prominent. Correlations between total FAN content and diacetyl concentration were calculated, as diacetyl is a precursor in the biosynthesis pathway of the amino acids valine and leucine. However, in this experiment, no correlation of amino acid and diacetyl concentration was observed between dry-hopped and traditional fermentations.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"242 - 254"},"PeriodicalIF":2.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47176005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：