Special Issue "Beer Quality and Flavour"

A special issue of Beverages (ISSN 2306-5710).

Deadline for manuscript submissions: closed (31 December 2020).

Special Issue Editors

Prof. Dr. Luis F. Guido
E-Mail Website
Guest Editor
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
Interests: food chemistry; food analysis; food control; food quality; analytical chemistry; brewing chemistry; malting chemistry
Special Issues and Collections in MDPI journals
Prof. Dr. Pavel Dostálek
E-Mail Website
Guest Editor
Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
Interests: health promoting compounds in brewing raw materials (hops, barley and beer); microbiological, colloidal, and sensorial stability of beer; microbial contaminants in beer and raw materials; authentication of beer and brewing raw materials; study of the properties of brewing yeast; formation, stability, and decomposition of beer foam; development of new products; development of new analytical methods

Special Issue Information

Dear Colleagues,

The flavour of beer, a complex balance of characters from malt, hops and yeast, deteriorates from the moment it is packaged, through the development of stale flavours typically found in long-term stored beers. During this time, beer flavour is changing most rapidly and the consumer is being exposed to products with variable taste, aroma and body. The term “off-flavour” is currently used for those negative flavours imparting negative quality characteristics.

When beer is drunk, its aroma is judged first as the glass is raised towards the mouth; then, aroma and taste are judged together when the product is in the mouth prior to swallowing. The aftertaste then remains. This is the overall quality of flavour and is the ultimate standard by which beer must be evaluated. Delaying flavour staling, to prolong shelf life, is therefore one of the greatest challenges facing the brewing industry today. Most routes contributing to the changes that take place in the flavour chemistry of beer interact in a complex and dynamic way, providing brewers and investigators with a wide and stimulating field of research.

This Special Issue, “Beer Quality and Flavour”, is aimed at giving the floor to the brewers who wish to share their findings, as well as to academic and industrial researchers. Coverage will include a selection of original research and current review articles related to the factors involved in beer quality, with a particular emphasis on the following:

  • Raw materials;
  • Malting technology;
  • Brewing technology;
  • Brewing yeast and fermentation;
  • Aroma and flavour;
  • Sensory analysis; and
  • Consumer research.

Prof. Luis F. Guido
Prof. Dr. Pavel Dostálek
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Beverages is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Flavour
  • Organoleptic
  • Aroma
  • Aging
  • Staling
  • Brewing
  • Malting
  • Sensory analysis

Published Papers (15 papers)

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Research

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Open AccessArticle
Refining Citrus Wastes: From Discarded Oranges to Efficient Brewing Biocatalyst, Aromatic Beer, and Alternative Yeast Extract Production
Beverages 2021, 7(2), 16; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages7020016 - 31 Mar 2021
Viewed by 237
Abstract
Agro-industrial wastes can be valorized as biorefinery raw materials through innovative, environmentally friendly bioprocessing for added value products. In this study, a process for citrus waste valorization within the biorefinery concept is proposed, including the development of an effective biocatalyst, based on immobilized [...] Read more.
Agro-industrial wastes can be valorized as biorefinery raw materials through innovative, environmentally friendly bioprocessing for added value products. In this study, a process for citrus waste valorization within the biorefinery concept is proposed, including the development of an effective biocatalyst, based on immobilized cells, for aromatic beer production, and an alternative yeast extract (AYE) production in the same unit. Specifically, orange pulp from discarded oranges was applied as an immobilization carrier of the alcohol-resistant and cryotolerant yeast strain S. cerevisiae AXAZ-1. The yeast culture was produced by minor nutrient supplementation using diluted molasses as substrate. An effective Citrus Waste Brewing Biocatalyst (CWBB) was produced and applied for beer fermentation. The aroma-related compounds in beer produced with free yeast cells or the CWBB were evaluated by solid-phase micro-extraction (SPME) gas chromatography–mass spectrometry (GC–MS). The analysis showed that the beers produced by the CWBB had a more complex volatile profile compared with beer fermented by the free cells. More specifically, the CWBB enhanced the formation of esters and terpenes by 5- and 27-fold, respectively. In the frame of the proposed multiprocessing biorefinery concept, the spent CWBB, after it has completed its cycle of brewing batches, was used as substrate for AYE production through autolysis. The produced AYE significantly affected the yeast growth when compared to commercial yeast extract (CYE). More specifically, it promoted the biomass productivity and biomass yield factor by 60–150% and 110–170%, respectively. Thus, AYE could be successfully used for industrial cell growth as an efficient and cheaper substitute of CYE. Within a circular economy framework, the present study highlights the potential use of citrus waste to produce aromatic beer combined with AYE production as an alternative way to valorize these wastes. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessCommunication
Brewery Packaging in a Post-COVID Economy within the United States
Beverages 2021, 7(1), 14; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages7010014 - 04 Mar 2021
Viewed by 455
Abstract
The 2020 pandemic caused by the novel coronavirus, SARS-CoV-2, also referred to as the COVID-19 [named for the disease caused by the virus] pandemic, shook the world to its core. Not only were populations hurt by the virus physically, the pandemic had deep [...] Read more.
The 2020 pandemic caused by the novel coronavirus, SARS-CoV-2, also referred to as the COVID-19 [named for the disease caused by the virus] pandemic, shook the world to its core. Not only were populations hurt by the virus physically, the pandemic had deep repercussions economically as well. One of the industries severely impacted by the implications of the 2020 COVID-19 pandemic was the brewing industry, particularly that of the United States. The economic turmoil and uncertainty were felt by both macro and micro brewers alike. Draft beer sales virtually dried up overnight as state-imposed shutdowns closed bars, restaurants, and taprooms as a means to curb the spread of the virus. There were supply chain and logistical issues that arose during the pandemic due to not only closures within the brewing industry but supporting industries such as printers and shippers. In some cases, entire business models had to be turned completely on their head in an instant and business pivots had to be made. The year 2020 was wrought with challenges faced by the brewing industry. There was one saving grace however that kept many breweries afloat during the pandemic, and that was packaged beverage sales, especially those packages intended for off-site consumption. Set forth by trends of the pre-pandemic years aluminum cans and canning reigned supreme for the craft brewing market and allowed breweries to get product into the hands of consumers and ultimately allowed some breweries to stay open. Other options breweries had included the use of glass growlers or aluminum crowlers as a means to sell draft products to-go. The resourcefulness of many brewery owners was tested in 2020 and many rose to the challenge. This report aims to examine several of the challenges, pivots, and solutions packaging provided to the beer industry during the pandemic. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessFeature PaperArticle
Optimization of Beer Brewing by Monitoring α-Amylase and β-Amylase Activities during Mashing
Beverages 2021, 7(1), 13; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages7010013 - 02 Mar 2021
Viewed by 533
Abstract
(1) Background: In the current highly competitive brewing industry, most breweries may benefit from a reduction in mashing time. In this study, a novel enzymatic assay format was used to investigate the activities of α-amylase and β-amylase during different mashing profiles, with the [...] Read more.
(1) Background: In the current highly competitive brewing industry, most breweries may benefit from a reduction in mashing time. In this study, a novel enzymatic assay format was used to investigate the activities of α-amylase and β-amylase during different mashing profiles, with the aim to use it as a tool for optimizing the production time of an existing industrial mashing process; (2) Methods: Lab-scale mashings with eight different time-temperature programs and two different pilot brews were analyzed in terms of enzymatic activity, sugar composition, alcohol by volume in the final beer, FAN and others; (3) Results: A 20-min reduction (out of an original 73-min mashing program) was achieved by selecting a temperature profile which maintained a higher enzymatic activity than the original, without affecting the wort sugar composition and fermentability, or the ethanol concentration and foam stability of the final beer. (4) Conclusions: A method is presented which can be used by breweries to optimize their mashing profiles based on monitoring α-amylase and β-amylase activities. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessFeature PaperArticle
Brewing with Unmalted Cereal Adjuncts: Sensory and Analytical Impacts on Beer Quality
Beverages 2021, 7(1), 4; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages7010004 - 15 Jan 2021
Cited by 1 | Viewed by 1229
Abstract
Brewing with unmalted cereal adjuncts can reduce the requirement for malting, thereby lowering costs and improving the overall sustainability of the brewing chain. However, substantial adjunct usage has technological challenges and the sensory characteristics of beers produced using high adjunct rates are still [...] Read more.
Brewing with unmalted cereal adjuncts can reduce the requirement for malting, thereby lowering costs and improving the overall sustainability of the brewing chain. However, substantial adjunct usage has technological challenges and the sensory characteristics of beers produced using high adjunct rates are still not fully understood. This study examined the impacts of brewing with unmalted barley, wheat, rice and maize at relatively high concentrations (0, 30% and 60% of grist) on the sensorial and analytical profiles of lager beer. Adjunct based beers and a 100% malt control were brewed at 25 L scale. A trained sensory panel (n = 8) developed a lexicon and determined the sensorial profile of beers. At 30% adjunct incorporation there was insignificant variation in the expected beer flavour profile. At 60% adjunct incorporation, there were some significant sensory differences between beers which were specific to particular adjunct materials. Furthermore, 60% adjunct inclusion (with correspondingly low wort FAN) impacted the fermentation volatile profile of the final beers which corresponded with findings observed in the sensory analysis. Developing an understanding of adjunct-induced flavour differences and determining strategies to minimise these differences will facilitate the implementation of cost-efficient and sustainable grist solutions. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessArticle
Investigation of Alcohol Factor Influence in Quantitative Descriptive Analysis and in the Time-Intensity Profile of Alcoholic and Non-Alcoholic Commercial Pilsen Beers Samples
Beverages 2020, 6(4), 73; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6040073 - 21 Dec 2020
Viewed by 1268
Abstract
In recent years, non-alcoholic beers have presented a growth considered satisfactory and exciting for the brewing industry. Such growth is allied to a change in the consumer profile, in addition to changes in traffic laws. However, the consumer seeks a product considered healthier, [...] Read more.
In recent years, non-alcoholic beers have presented a growth considered satisfactory and exciting for the brewing industry. Such growth is allied to a change in the consumer profile, in addition to changes in traffic laws. However, the consumer seeks a product considered healthier, but as tasty as the original. Thus, this study aimed to identify the influence of the alcoholic factor in sensory profile, through quantitative descriptive analysis and time intensity analysis of Pilsen beer samples. An acceptance test with 120 consumers of beer was performed. A quantitative descriptive analysis was carried out by 11 trained assessors to determine the sensory profile of beers. For identification of influences of alcohol factor in the dynamic profile of alcoholic flavor and bitter taste the time-intensity analysis were realized. The results demonstrate that alcohol factor influences both the quantitative descriptive profile and dynamic profile, in addition the correlations between the quantitative descriptive analysis (QDA®) and hedonic data show that the alcoholic flavor and the alcoholic aroma are attributes that contribute positively to acceptance of samples. In view of the results, studies such as the present are of great importance for the improvement of product quality, directly reflecting a greater acceptance of beer consumers. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessCommunication
Investigating the Potential of an In-Situ Method for Monitoring the Malting of Barley Using Solid Phase Microextraction with a Portable Gas Chromatography Mass Spectrometry Instrument
Beverages 2020, 6(4), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6040072 - 20 Dec 2020
Viewed by 662
Abstract
An improved understanding of the malting process could have a significant impact on the efficient production of quality malt for the brewing industry. Analysis of volatile organic compounds produced during the malting process is one approach towards achieving this goal. In-situ methods avoid [...] Read more.
An improved understanding of the malting process could have a significant impact on the efficient production of quality malt for the brewing industry. Analysis of volatile organic compounds produced during the malting process is one approach towards achieving this goal. In-situ methods avoid the possibility of contamination and chemical changes occurring during sample transport and storage. This paper describes the investigation of an in-situ sampling method for the detection of volatile organic compounds produced during the malting of barley. Solid Phase Microextraction Gas Chromatography Mass Spectrometry (SPME-GC/MS) was used to identify compounds. The investigated method involved the direct exposure of an SPME fiber in the kiln during barley malting. Using this method, compounds including aldehydes, ketones, and esters were detected. Some changes in volatile organic compound composition were observed during the production of pale malt at a commercial malting house. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessArticle
The Influence of Bottle Design on Perceived Quality of Beer: A Conjoint Analytic Study
Beverages 2020, 6(4), 64; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6040064 - 10 Nov 2020
Viewed by 1000
Abstract
Research on the influence of packaging on consumer perception of beer and other alcoholic beverages suggest an important role in capturing consumers’ attention and generating expectations on perceived product quality, and in particular that color, bottle shape, and label design are key aspects. [...] Read more.
Research on the influence of packaging on consumer perception of beer and other alcoholic beverages suggest an important role in capturing consumers’ attention and generating expectations on perceived product quality, and in particular that color, bottle shape, and label design are key aspects. There is, however, a paucity of research looking at interactions between different aspects of packaging design. This is a topical issue given an increasingly saturated market where especially craft breweries strive for differentiation and brand recognition. Situated within this context, the present research used a conjoint analytic approach to investigate the effect of packaging design on consumer perceived quality and liking for beers. Beer images were designed to systematically vary in four design factors—label color, label shape, label complexity, and bottle shape—and evaluated in an online survey with a representative sample of Danish beer drinkers. Two of the design factors—label color and bottle type—significantly affected consumers’ product evaluations, whereas the other two factors did not. Post-hoc analyses of the main effects indicated that the combination of a “Bomber” bottle shape and a warm color scheme in the label as the optimal combination of design factors to maximize consumer preferences. Preference for the Bomber bottle was linked to a perceived premiumness associated with a preference for curvatures (as opposed to angularity), whereas the preference for warm colors was tentatively explained as due to crossmodal correspondences generating favorable sensory expectations for this color scheme. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessArticle
A Multi-Parameter, Predictive Model of Starch Hydrolysis in Barley Beer Mashes
Beverages 2020, 6(4), 60; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6040060 - 13 Oct 2020
Cited by 1 | Viewed by 809
Abstract
A key first step in the production of beer is the mashing process, which enables the solubilization and subsequent enzymatic conversion of starch to fermentable sugars. Mashing performance depends primarily on temperature, but also on a variety of other process parameters, including pH [...] Read more.
A key first step in the production of beer is the mashing process, which enables the solubilization and subsequent enzymatic conversion of starch to fermentable sugars. Mashing performance depends primarily on temperature, but also on a variety of other process parameters, including pH and mash thickness (known as the “liquor-to-grist” ratio). This process has been studied for well over 100 years, and yet essentially all predictive modeling efforts are alike in that only the impact of temperature is considered, while the impacts of all other process parameters are largely ignored. A set of statistical and mathematical methods collectively known as Response Surface Methodology (RSM) is commonly applied to develop predictive models of complex processes such as mashing, where performance depends on multiple parameters. For this study, RSM was used to design and test a set of experimental mash conditions to quantify the impact of four process parameters—temperature (isothermal), pH, aeration, and the liquor-to-grist ratio—on extract yield (total and fermentable) and extract composition in order to create a robust, yet simple, predictive model. In contrast to previous models of starch hydrolysis in a mash, a unique aspect of the model developed here was the quantification of significant parameter interaction effects, the most notable of which was the interaction between temperature and mash thickness (i.e., the liquor-to-grist ratio). This interaction had a sizeable impact on important mash performance metrics, such as the total extract yield and the fermentability of the resultant wort. The development of this model is of great future utility to brewery processing, as it permits the multi-parameter optimization of the mashing process. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessFeature PaperArticle
Brewing Characteristics of the Maltotriose-Positive Yeast Zygotorulaspora florentina Isolated from Oak
Beverages 2020, 6(4), 58; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6040058 - 24 Sep 2020
Viewed by 993
Abstract
The use of wild yeasts in fermentation is becoming a viable option for the differentiation of beers. To achieve good fermentation rates and alcohol yields, however, such yeasts must have the ability to utilize the wort sugars maltose and maltotriose, a relatively rare [...] Read more.
The use of wild yeasts in fermentation is becoming a viable option for the differentiation of beers. To achieve good fermentation rates and alcohol yields, however, such yeasts must have the ability to utilize the wort sugars maltose and maltotriose, a relatively rare trait amongst non-domesticated yeasts. Zygotorulaspora florentina is a species with the ability to utilize both sugars, and was evaluated here with respect to its brewing potential. The strain studied (VTT C-201041) was isolated from bark of an oak tree (Quercus robur) in Espoo, Finland. The fermentation performance of the strain was compared to that of two ale yeasts as well as the species type strain (VTT C-94199). Both Z. florentina strains fermented wort efficiently (apparent attenuation levels >77%). While the type strain had the highest yield, the Finnish strain produced more volatile aroma compounds. The species is capable of decarboxylating ferulic acid to produce the spice/clove-like compound 4-vinylguaiacol, which was present in beers at a concentration above the typical flavor threshold. The characteristic flavor of 4-vinylguaiacol was not however perceptible in taste trials, possibly due to the masking effect of other compounds. The potential of this species for industrial application is discussed, particularly in relation to its apparent ethanol sensitivity. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessArticle
Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer
Beverages 2020, 6(3), 48; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6030048 - 03 Aug 2020
Cited by 1 | Viewed by 1301
Abstract
Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of [...] Read more.
Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of brewing and dry-hopping using hops treated with copper-based fungicides (CBFs) on the final transition metal content of model buffer solutions and pilot-scale systems of wort and beer. Copper levels in model wort and beer solutions were elevated (105.6% and 230.4% increase, respectively) when CBF-treated hops were used. In laboratory-prepared wort, elevated copper concentrations were not observed when CBF-treated hops were used for boiling. Dry hopping of beer using CBF-treated hops led to significant increases in total copper content (ca. 75 µg/kg vs. ca. 40–50 µg/kg in the control-hopped beer) when yeast was absent from the treated beer, but not when yeast was present. It was observed that manganese levels were significantly elevated in all hopped beers (ca. 495–550 µg/kg vs. 90–125 µg/kg in the unhopped control), regardless of hop treatment. A hop varietal thiol, 4-Mercapto-4-methylpentan-2-one, was spiked into treated beers, and the rate of oxidative loss was monitored during aging. Rates of thiol loss in treated beer samples did not differ across CBF treatments but were significantly lower in unhopped controls in the absence of yeast (p < 0.0001) and correlated significantly with total manganese content of the beers (R2 = 0.4228, p = 0.0006). The rate of staling in hopped beers as measured by the rate of 1-hydroxyethyl radical generation did not differ among hop treatments, suggesting that excess copper content contributed from the hops does not negatively impact the oxidative stability of the beers. These findings suggest that brewers can use CBF-treated hops without any negative implications for the shelf stability of their beers and do not contraindicate the use of CBF in hops production when necessary. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessArticle
Happy Hour? A Preliminary Study of the Effect of Induced Joviality and Sadness on Beer Perception
Beverages 2020, 6(2), 35; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6020035 - 01 Jun 2020
Cited by 2 | Viewed by 1327
Abstract
Our emotions influence our perception. In order to determine whether emotion influences the perception of beer, 32 participants watched either a scene from the movie Wall-E to induce joviality, or a short clip from the Shawshank Redemption to induce sadness. The participants were [...] Read more.
Our emotions influence our perception. In order to determine whether emotion influences the perception of beer, 32 participants watched either a scene from the movie Wall-E to induce joviality, or a short clip from the Shawshank Redemption to induce sadness. The participants were then required to sample up to 250 mL of Yenda Pale Ale beer and rate it on a variety of taste and flavor characteristics (e.g., bitterness), before completing the Positive and Negative Affect Schedule-X (PANAS-X). The data were analyzed using Bayesian t-tests and Null Hypothesis Significance Tests (NHSTs). After applying conservative corrections for multiple comparisons, NHSTs failed to reach statistical significance. However, the effect sizes suggested that inducing joviality, relative to inducing sadness, resulted in the beer being rated as (a) tasting more pleasant, (b) tasting sweeter, and (c) being of higher quality. Following the induction of joviality, participants were also willing to pay more for the beer. The Bayesian analyses indicated that induced emotion can influence flavor perception for complex taste stimuli. The effect sizes and Bayesian analyses are interpreted in terms of Feelings-as-Information theory. These preliminary findings can tentatively be applied to real-world environments such as venues that serve and/or market alcohol. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
Open AccessArticle
Analysis of Lambic Beer Volatiles during Aging Using Gas Chromatography–Mass Spectrometry (GCMS) and Gas Chromatography–Olfactometry (GCO)
Beverages 2020, 6(2), 31; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6020031 - 11 May 2020
Viewed by 1080
Abstract
Lambic beer is produced using spontaneous fermentation. Gueuze is a style of lambic beer that blends “young” (1 year old) and “aged” (2+ years old) beers. Little is known about the development of volatile aroma compounds in lambic beer during aging. Solid-phase microextraction [...] Read more.
Lambic beer is produced using spontaneous fermentation. Gueuze is a style of lambic beer that blends “young” (1 year old) and “aged” (2+ years old) beers. Little is known about the development of volatile aroma compounds in lambic beer during aging. Solid-phase microextraction and gas chromatography–mass spectrometry were used to analyze volatile compounds from 3, 6, 9, 12, and 28-month-old commercial samples of lambic beer. Compounds were identified using standardized retention time and mass spectra of standards. Gas chromatography–olfactometry was used to characterize the aroma profiles of the samples. A total of 41 compounds were identified using gas chromatography–mass spectrometry (GC–MS). Ethyl lactate, ethyl acetate, 4-ethylphenol and 4-ethylguaiacol were identified in the 9, 12, and 28-month old samples. These four compounds have been linked to the microorganism Brettanomyces. Twenty-one aroma active compounds were identified using Gas chromatography–olfactometry (GC–O). As the age of the gueuze samples increased, a larger number of aroma compounds were identified by the panelists; the compounds identified increased from seven for the 3-month-old samples to nine for the 6-month-old samples, and eleven for both the nine and twelve-month-old samples, and seventeen for the twenty-eight-month-old samples. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
Open AccessArticle
Development of a Rapid Method to Assess Beer Foamability Based on Relative Protein Content Using RoboBEER and Machine Learning Modeling
Beverages 2020, 6(2), 28; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6020028 - 03 May 2020
Cited by 4 | Viewed by 1068
Abstract
Foam-related parameters are associated with beer quality and dependent, among others, on the protein content. This study aimed to develop a machine learning (ML) model to predict the pattern and presence of 54 proteins. Triplicates of 24 beer samples were analyzed through proteomics. [...] Read more.
Foam-related parameters are associated with beer quality and dependent, among others, on the protein content. This study aimed to develop a machine learning (ML) model to predict the pattern and presence of 54 proteins. Triplicates of 24 beer samples were analyzed through proteomics. Furthermore, samples were analyzed using the RoboBEER to evaluate 15 physical parameters (color, foam, and bubbles), and a portable near-infrared (NIR) device. Proteins were grouped according to their molecular weight (MW), and a matrix was developed to assess only the significant correlations (p < 0.05) with the physical parameters. Two ML models were developed using the NIR (Model 1), and RoboBEER (Model 2) data as inputs to predict the relative quantification of 54 proteins. Proteins in the 0–20 kDa group were negatively correlated with the maximum volume of foam (MaxVol; r = −0.57) and total lifetime of foam (TLTF; r = −0.58), while those within 20–40 kDa had a positive correlation with MaxVol (r = 0.47) and TLTF (r = 0.47). Model 1 was not as accurate (testing r = 0.68; overall r = 0.89) as Model 2 (testing r = 0.90; overall r = 0.93), which may serve as a reliable and affordable method to incorporate the relative quantification of important proteins to explain beer quality. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Review

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Open AccessFeature PaperReview
Bottle Conditioning: Technology and Mechanisms Applied in Refermented Beers
Beverages 2020, 6(3), 56; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6030056 - 09 Sep 2020
Cited by 1 | Viewed by 1023
Abstract
Bottle conditioning refers to a method of adding fermenting wort or yeast suspension in sugar solution into beer in its final package. Additionally denoted as bottle refermentation, this technique has been originally developed to assure beer carbonation, and has further significance related to [...] Read more.
Bottle conditioning refers to a method of adding fermenting wort or yeast suspension in sugar solution into beer in its final package. Additionally denoted as bottle refermentation, this technique has been originally developed to assure beer carbonation, and has further significance related to formation of distinctive sensory attributes and enhancement of sensory stability, which are the phenomena associated with ongoing yeast metabolic activities in the final package. This review covers historical development of the method, describes metabolic pathways applied during refermentation, and explains practical aspects of the refermentation process management. Furthermore, an overview of the traditional and novel approaches of bottle conditioning with mixed yeast bacterial cultures and its impact on the properties of final beer is provided. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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Open AccessReview
Functional Beer—A Review on Possibilities
Beverages 2020, 6(3), 51; https://0-doi-org.brum.beds.ac.uk/10.3390/beverages6030051 - 16 Aug 2020
Cited by 2 | Viewed by 1266
Abstract
The expansion of the beer industry has enabled many possibilities for improvement regarding the taste, aroma and functionality of this drink. Health-related issues and a general wish for healthier lifestyles has resulted in increased demand for functional beers. The addition of different herbs [...] Read more.
The expansion of the beer industry has enabled many possibilities for improvement regarding the taste, aroma and functionality of this drink. Health-related issues and a general wish for healthier lifestyles has resulted in increased demand for functional beers. The addition of different herbs or adjuncts in wort or beer has been known for centuries. However, today’s technologies provide easier ways to do this and offer additional functional properties for the health benefits and sensory adjustments of classical beer. Medicinal, religious or trendy reasons for avoiding certain compounds in beer or the need to involve new ones in the brewing recipe has broadened the market for the brewing industry and made beer more accessible to consumers who, till now, avoided beer. Full article
(This article belongs to the Special Issue Beer Quality and Flavour)
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