Fermentation

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12 pages, 1439 KiB

Open AccessArticle

Effects of Ultradisperse Humic Sapropel Suspension on Microbial Growth and Fermentation Parameters of Barley Distillate

by Daniel Nsengumuremyi, Parise Adadi, Maria V. Ukolova and Nadezhda V. Barakova

Fermentation 2019, 5(1), 24; https://doi.org/10.3390/fermentation5010024 - 26 Feb 2019

Cited by 6 | Viewed by 4648

Abstract

Barley and other cereal grains can be used in the production of ethanol. The quality and safety of the grains utilized have enormous effects on the overall yield and quality of the final product (ethanol). Therefore, the present paper seeks to elucidate the [...] Read more.

Barley and other cereal grains can be used in the production of ethanol. The quality and safety of the grains utilized have enormous effects on the overall yield and quality of the final product (ethanol). Therefore, the present paper seeks to elucidate the antimicrobial activities of ultradisperse humic sapropel suspensions (UDHSS) on barley, wort, fermentation, and the quality of the final product. A standard microbiological method was used to assess the biocidal activities. Physicochemical parameters and volatile compounds were determined. Treated samples exhibited least microbial growth (for grain: 1.145 ± 0.120 × 10⁴ cfu/g) when compared to the control (3.425 ± 0.33 × 10⁵ cfu/g). Mash from the treated sample had less Free Amino Nitrogen (35.14 ± 0.02 mg/L) than the control experiment (41.42 ± 0.01). However, the levels of °Brix and Free Amino Nitrogen (FAN) were unaffected by the UDHSS treatments. After the chromatographic analysis, it was revealed that the barley distillate obtained from treated grains had high volatiles concentration when compared to the control experiment. The volume of the methanol quantified in the distillate was low, and hence safe, and might find applications in the food industries or in domestic consumption after rectification. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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19 pages, 2552 KiB

Open AccessFeature PaperArticle

Application of Non-Saccharomyces Yeasts Isolated from Kombucha in the Production of Alcohol-Free Beer

by Konstantin Bellut, Maximilian Michel, Martin Zarnkow, Mathias Hutzler, Fritz Jacob, David P. De Schutter, Luk Daenen, Kieran M. Lynch, Emanuele Zannini and Elke K. Arendt

Fermentation 2018, 4(3), 66; https://doi.org/10.3390/fermentation4030066 - 17 Aug 2018

Cited by 74 | Viewed by 21077

Abstract

Alcohol-free beer (AFB) is no longer just a niche product in the beer market. For brewers, this product category offers economic benefits in the form of a growing market and often a lower tax burden and enables brewers to extend their product portfolio [...] Read more.

Alcohol-free beer (AFB) is no longer just a niche product in the beer market. For brewers, this product category offers economic benefits in the form of a growing market and often a lower tax burden and enables brewers to extend their product portfolio and promote responsible drinking. Non-Saccharomyces yeasts are known for their flavor-enhancing properties in food fermentations, and their prevailing inability to ferment maltose and maltotriose sets a natural fermentation limit and can introduce a promising approach in the production of AFB (≤0.5% v/v). Five strains isolated from kombucha, Hanseniaspora valbyensis, Hanseniaspora vineae, Torulaspora delbrueckii, Zygosaccharomyces bailii and Zygosaccharomyces kombuchaensis were compared to a commercially applied AFB strain Saccharomycodes ludwigii and a Saccharomyces cerevisiae brewer’s yeast. The strains were characterized for their sugar utilization, phenolic off-flavors, hop sensitivity and flocculation. Trial fermentations were analyzed for extract reduction, ethanol formation, pH drop and final beers were analyzed for amino acids utilization and fermentation by-products. The performance of non-Saccharomyces strains and the commercial AFB strain were comparable during fermentation and production of fermentation by-products. An experienced sensory panel could not discriminate between the non-Saccharomyces AFB and the one produced with the commercial AFB strain, therefore indicating their suitability in AFB brewing. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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9 pages, 918 KiB

Open AccessArticle

Identification of Microflora in a Biological Brewer’s Wort Acidification Process Run Continuously for 20 Years

by Mathias Hutzler, Jana Čmielová, Tobias Frank, Andreas Brandl, Fritz Jacob and Maximilian Michel

Fermentation 2018, 4(3), 51; https://doi.org/10.3390/fermentation4030051 - 4 Jul 2018

Cited by 1 | Viewed by 5414

Abstract

Biological acidification is a common and beneficial way for breweries to adjust the pH value of their mash or wort to improve enzymatic activity during mashing, raise yeast activity during fermentation, and increase the flavor stability of the finished beer. The reactors are [...] Read more.

Biological acidification is a common and beneficial way for breweries to adjust the pH value of their mash or wort to improve enzymatic activity during mashing, raise yeast activity during fermentation, and increase the flavor stability of the finished beer. The reactors are mostly run for many years without re-inoculating a fresh culture, creating the possibility of changes in the culture, genetic drifts, or the survival of different strains. In this study, a biological acidification culture that had been continuously run for 20 years was analyzed by GTG5 PCR and IGS2-314 rDNA PCR fingerprinting, as well as 16S and 26S rDNA sequencing, and real-time PCR was applied to differentiate the bacterial and yeast strains and species. The applied real-time PCR primers for Lactobacillus amylolyticus and Lactobacillus amylovorus have not been published yet. It was shown that only strains of the species L. amylolyticus were present, with low contamination of yeast strains from the species Saccharomyces cerevisiae. As the original starter culture was Lactobacillus amylolyticus, the acidification plant ran for 20 years, and no Lactobacillus sp. cross-contamination could be analyzed using culture-dependent methods after 20 years. The microflora composition is a decisive factor for the final beer flavor. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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17 pages, 1240 KiB

Open AccessFeature PaperArticle

Micro-Malting for the Quality Evaluation of Rye (Secale cereale) Genotypes

by Yujuan Wang, Zhao Jin, John Barr, James Gillespie, Senay Simsek, Richard D. Horsley and Paul B. Schwarz

Fermentation 2018, 4(3), 50; https://doi.org/10.3390/fermentation4030050 - 27 Jun 2018

Cited by 11 | Viewed by 6257

Abstract

Malting of rye and the use of rye malts presents several challenges to maltsters and brewers, like the lack of a hull, dense packing in steep, and high wort viscosity. While empirical evidence shows that rye genotypes differ in malting and brewing performance [...] Read more.

Malting of rye and the use of rye malts presents several challenges to maltsters and brewers, like the lack of a hull, dense packing in steep, and high wort viscosity. While empirical evidence shows that rye genotypes differ in malting and brewing performance and flavor, there is little published information on the malting of rye or the malt quality attributes of rye genotypes. The objective was to evaluate laboratory micro-malting conditions that could be used in quality screening. Parameters included germination time, moisture and kernel size. Wort arabinoxylan and phenolic acid contents were determined in addition to standard malt quality parameters. In general, high extract and lower viscosity were achieved by malting for at least 4 days at 45%–48% moisture under the temperature of 16 °C. However, as some commercial maltsters indicated the difficulty of handling of germinating rye at the highest moisture levels, we recommend 5 days of germination at 45% moisture for the future evaluation of rye cultivars. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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Review

Jump to: Research

11 pages, 2291 KiB

Open AccessReview

Free Amino Nitrogen in Brewing

by Annie E. Hill and Graham G. Stewart

Fermentation 2019, 5(1), 22; https://doi.org/10.3390/fermentation5010022 - 18 Feb 2019

Cited by 97 | Viewed by 18118

Abstract

The role of nitrogenous components in malt and wort during the production of beer has long been recognized. The concentration and range of wort amino acids impact on ethanolic fermentation by yeast and on the production of a range of flavour and aroma [...] Read more.

The role of nitrogenous components in malt and wort during the production of beer has long been recognized. The concentration and range of wort amino acids impact on ethanolic fermentation by yeast and on the production of a range of flavour and aroma compounds in the final beer. This review summarizes research on Free Amino Nitrogen (FAN) within brewing, including various methods of analysis. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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12 pages, 1320 KiB

Open AccessReview

Beer–The Importance of Colloidal Stability (Non-Biological Haze)

by Kristina Mastanjević, Vinko Krstanović, Jasmina Lukinac, Marko Jukić, Zdravko Vulin and Krešimir Mastanjević

Fermentation 2018, 4(4), 91; https://doi.org/10.3390/fermentation4040091 - 2 Nov 2018

Cited by 41 | Viewed by 18894

Abstract

Today’s beer differs in many ways from the original hazy brew made from grains and water left in the sun to ferment. The development of brewing procedures introduced filtration and colloidal stabilization as key elements in beer preservation and stability. Colloidal stability of [...] Read more.

Today’s beer differs in many ways from the original hazy brew made from grains and water left in the sun to ferment. The development of brewing procedures introduced filtration and colloidal stabilization as key elements in beer preservation and stability. Colloidal stability of beer is the most important factor in beer quality. Colloidal particles significantly shorten beer’s storage time, but most importantly, also influence its appearance. Colloidal stabilization involves one or more procedures that are applied at different stages during production and result in colloidal stability of the final product. Beer is considered to be colloidal stable if it can be stored for several months at 25 °C without exhibiting any changes in composition or other properties; specifically, beer has to be able to remain clear without any signs of precipitation. Since colloidal stability is of primary importance for the consumer, retail requirements have resulted in many solutions for this issue. Stabilization agents have to be reliable during the filtration and stabilization processes. Additionally, renewable agents are highly desirable. The level of colloidal stability required depends on the desired storage time and temperature after the beer has been packed. Consumers have higher and higher expectations that the industry has to follow. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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9 pages, 221 KiB

Open AccessReview

A Review on the Source of Lipids and Their Interactions during Beer Fermentation that Affect Beer Quality

by Russell Gordon, Aoife Power, James Chapman, Shaneel Chandra and Daniel Cozzolino

Fermentation 2018, 4(4), 89; https://doi.org/10.3390/fermentation4040089 - 24 Oct 2018

Cited by 29 | Viewed by 8255

Abstract

The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour [...] Read more.

The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour potential. In addition, beer foam stability can be influenced by the concentration of lipids as well as other factors such as hop acids (e.g., iso-α-acids), proteins, polysaccharides and the presence of metal ions (e.g., nickel). Lipids can also influence yeast protease activity as well as the production of ethanol. This review provides an overview of the effect of climate change on the chemical composition of barley in relation to lipids and the influence of lipids in the process of this raw material in order to produce beer. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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32 pages, 32191 KiB

Open AccessReview

Yeast Flocculation—Sedimentation and Flotation

by Graham G. Stewart

Fermentation 2018, 4(2), 28; https://doi.org/10.3390/fermentation4020028 - 16 Apr 2018

Cited by 40 | Viewed by 30743

Abstract

Unlike most fermentation alcohol beverage production processes, brewers recycle their yeast. This is achieved by employing a yeast culture’s: flocculation, adhesion, sedimentation, flotation, and cropping characteristics. As a consequence of yeast recycling, the quality of the cropped yeast culture’s characteristics is critical. However, [...] Read more.

Unlike most fermentation alcohol beverage production processes, brewers recycle their yeast. This is achieved by employing a yeast culture’s: flocculation, adhesion, sedimentation, flotation, and cropping characteristics. As a consequence of yeast recycling, the quality of the cropped yeast culture’s characteristics is critical. However, the other major function of brewer’s yeast is to metabolise wort into ethanol, carbon dioxide, glycerol, and other fermentation products, many of which contribute to beer’s overall flavour characteristics. This review will only focus on brewer’s yeast flocculation characteristics. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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13 pages, 4857 KiB

Open AccessReview

Impact of Wort Amino Acids on Beer Flavour: A Review

by Inês M. Ferreira and Luís F. Guido

Fermentation 2018, 4(2), 23; https://doi.org/10.3390/fermentation4020023 - 28 Mar 2018

Cited by 114 | Viewed by 17249

Abstract

The process by which beer is brewed has not changed significantly since its discovery thousands of years ago. Grain is malted, dried, crushed and mixed with hot water to produce wort. Yeast is added to the sweet, viscous wort, after which fermentation occurs. [...] Read more.

The process by which beer is brewed has not changed significantly since its discovery thousands of years ago. Grain is malted, dried, crushed and mixed with hot water to produce wort. Yeast is added to the sweet, viscous wort, after which fermentation occurs. The biochemical events that occur during fermentation reflect the genotype of the yeast strain used, and its phenotypic expression is influenced by the composition of the wort and the conditions established in the fermenting vessel. Although wort is complex and not completely characterized, its content in amino acids indubitably affects the production of some minor metabolic products of fermentation which contribute to the flavour of beer. These metabolic products include higher alcohols, esters, carbonyls and sulfur-containing compounds. The formation of these products is comprehensively reviewed in this paper. Furthermore, the role of amino acids in the beer flavour, in particular their relationships with flavour active compounds, is discussed in light of recent data. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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13 pages, 702 KiB

Open AccessFeature PaperReview

The Impact of Simple Phenolic Compounds on Beer Aroma and Flavor

by Michael Lentz

Fermentation 2018, 4(1), 20; https://doi.org/10.3390/fermentation4010020 - 19 Mar 2018

Cited by 62 | Viewed by 16827

Abstract

Beer is a complex beverage containing a myriad of flavor- and aroma-active compounds. Brewers strive to achieve an appropriate balance of desired characters, while avoiding off-aromas and flavors. Phenolic compounds are always present in finished beer, as they are extracted from grains and [...] Read more.

Beer is a complex beverage containing a myriad of flavor- and aroma-active compounds. Brewers strive to achieve an appropriate balance of desired characters, while avoiding off-aromas and flavors. Phenolic compounds are always present in finished beer, as they are extracted from grains and hops during the mashing and brewing process. Some of these compounds have little impact on finished beer, while others may contribute either desirable or undesirable aromas, flavors, and mouthfeel characteristics. They may also contribute to beer stability. The role of simple phenolic compounds on the attributes of wort and beer are discussed. Full article

(This article belongs to the Special Issue Brewing & Distilling)

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