Preference segments among declared craft beer drinkers: Perceptual, attitudinal and behavioral responses underlying craft-style vs. traditional-style flavor preferences

A Review of N-Heterocycles: Mousy Off-Flavor in Sour Beer

Beer has over 600 flavor compounds and creates a positive tasting experience with acceptable sensory properties, which are essential for the best consumer experience. Spontaneous and mixed-culture fermentation beers, generally classified as sour beers, are gaining popularity compared to typical lager or ale styles, which have dominated in the USA for the last few decades. Unique and acceptable flavor compounds characterize sour beers, but some unfavorable aspects appear in conjunction. One such unfavorable flavor is called "mousy". This description is usually labeled as an unpleasant odor, identifying spoilage of fermented food and beverages. It is related as having the odor of mouse urine, cereal, corn tortilla chips, or freshly baked sour bread. The main compounds responsible for it are N-heterocyclic compounds: 2-acetyltetrahydropyridine, 2-acetyl-1-pyrroline, and 2-ethyltetrahydropyridine. The most common beverages associated with mousy off-flavor are identified in wines, sour beers, other grain-based beverages, and kombucha, which may contain heterofermentative lactic acid bacteria, acetic acid bacteria, and/or yeast/fungus cultures. In particular, the fungal species Brettanomyces bruxellensis are associated with mousy-off flavor occurrence in fermented beverages matrices. However, many factors for N-heterocycle formation are not well-understood. Currently, the research and development of mixed-cultured beer and non/low alcohol beverages (NABLAB) has increased to obtain the highest quality, sensory, functionality, and most notably safety standards, and also to meet consumers' demand for a balanced sourness in these beverages. This paper introduces mousy off-flavor expression in beers and beverages, which occurs in spontaneous or mixed-culture fermentations, with a focus on sour beers due to common inconsistency aspects in fermentation. We discuss and suggest possible pathways of mousy off-flavor development in the beer matrix, which also apply to other fermented beverages, including non/low alcohol drinks, e.g., kombucha and low/nonalcohol beers. Some precautions and modifications may prevent the occurrence of these off-flavor compounds in the beverage matrix: improving raw material quality, adjusting brewing processes, and using specific strains of yeast and bacteria that are less likely to produce the off-flavor. Conceivably, it is clear that spontaneous and mixed culture fermentation is gaining popularity in industrial, craft, and home brewing. The review discusses important elements to identify and understand metabolic pathways, following the prevention of spoilage targeted to off-flavor compounds development in beers and NABLABs.

Breeding of high-tolerance yeast by adaptive evolution and high-gravity brewing of mutant

BACKGROUND

Ethanol and osmotic stresses are the major limiting factors for brewing strong beer with high-gravity wort. Breeding of yeast strains with high osmotic and ethanol tolerance and studying very-high-gravity (VHG) brewing technology is of great significance for brewing strong beer.

RESULTS

This study used an optimized microbial microdroplet culture (MMC) system for adaptive laboratory evolution (ALE) of Saccharomyces cerevisiae YN81 to improve its tolerance to osmotic and ethanol stress. Meanwhile, we investigated the VHG and VHG with added ethanol (VHGAE) brewing processes for the evolved mutants in brewing strong beer. The results showed that three evolved mutants were obtained; among them, the growth performance of YN81mc-8.3 under 300, 340, 380, 420 and 460 g L-1 sucrose stresses was greater than that of the other strains. The ethanol tolerance of YN81mc-8.3 was 12%, which was 20% higher than that of YN81. During strong-beer brewing in a 100 L cylindrical cone-bottom tank, the sugar utilization and ethanol yield of YN81mc-8.3 outperformed those of YN81 in both the VHG and VHGAE brewing processes. Measurement of the diacetyl concentration showed that YN81mc-8.3 had a stronger diacetyl reduction ability; in particular, the real degree of fermentation of beers brewed by YN81mc-8.3 in VHG and VHGAE brewing processes was 75.35% and 66.71%, respectively - higher than those of the two samples brewed by YN81. Meanwhile, the visual, olfactive and gustative properties of the strong beer produced by YN81mc-8.3 were better than those of the other beers.

CONCLUSION

In this study, the mutant YN81mc-8.3 and the VHGAE brewing process were optimal and represented a better alternative strong-beer brewing process. © 2023 Society of Chemical Industry.

Assessment of green lentil malt as a substrate for gluten-free beer brewing

The aim of this study was to analyze whether it is possible to brew beer without using cereals so that the produced beverage could be easily accessible for the population suffering from celiac disease and other gluten-related disorders. Green lentil seeds were malted and then mashed using a congress mashing procedure to assess their advantages and disadvantages in the brewing process. Based on the congress mashing procedure, the mashing process needed to produce beer was developed, and beers were produced from the lentil malts germinated during malting for 96 h, 120 h and 144 h. It was possible to produce beers from the lentil malts; however, they were characterized by a lower alcohol content, lower degree of attenuation and some discrepancies between the concentrations of various volatiles (such as acetaldehyde, ethyl acetate, and 1-propanol) compared to the control beer produced from barley malt.

Wheat craft beer made from AFB1-contaminated wheat malt contains detectable mycotoxins, retains quality attributes, but differs in some fermentation metabolites

Levels of aflatoxin B1 (AFB1) were measured during the production of wheat craft beer made with wheat malt contaminated with AFB1 (1.23 µg/kg). A wheat craft beer made with non-contaminated wheat malt was produced for comparison purposes. AFB1 was measured after mashing (malt after the mashing process), and in spent grain (spent grains are filtered to collect the wort - remaining sugar-rich liquid), sweet wort, green beer, spent yeast, and in beer. Physicochemical parameters (pH, titratable acidity, color parameters, total soluble solids), sugars, organic acids, alcohols, and phenolics were evaluated after mashing, and in sweet wort, green beer, and beer samples. Density and yeast counts were determined over 120 h of sweet wort fermentation every 24 h. The AFB1 levels in the final beer were 0.22 µg/L, while the spent grains and spent yeasts contained 0.71 ± 0.17 and 0.11 ± 0.03 µg/kg of AFB1, respectively. AFB1 contamination did not influence the final product's physicochemical parameters, density during fermentation, fructose, or glycerol content. Higher yeast counts were observed during the first 48 h of non-contaminated wheat craft beer fermentation, with higher ethanol, citric acid, and propionic acid contents and lower glucose, malic acid, and lactic acid contents compared with beer contaminated with AFB1. Non-contaminated wheat craft beer also had higher concentrations of gallic acid, chlorogenic acid, catechin, procyanidin A2, and procyanidin B1. AFB1 contamination of wheat malt may not affect basic quality parameters in wheat craft beer but can influence the final product's organic acid and phenolic contents. Our findings show that if wheat craft beer is made with contaminated malt, AFB1 can remain in the final product and may pose a risk to consumers.

A comprehensive review of the benefits of drinking craft beer: Role of phenolic content in health and possible potential of the alcoholic fraction

Currently, there is greater production and consumption of craft beer due to its appreciated sensory characteristics. Unlike conventional beer, craft beers provide better health benefits due to their varied and high content of phenolic compounds (PCs) and also due to their alcohol content, but the latter is controversial. The purpose of this paper was to report on the alcoholic fraction and PCs present in craft beers and their influence on health. Despite the craft beer boom, there are few studies on the topic; there is a lot of field to explore. The countries with the most research are the United States > Italy > Brazil > United Kingdom > Spain. The type and amount of PCs in craft beers depends on the ingredients and strains used, as well as the brewing process. It was determined that it is healthier to be a moderate consumer of alcohol than to be a teetotaler or heavy drinker. Thus, studies in vitro, with animal models and clinical trials on cardiovascular and neurodegenerative diseases, cancer, diabetes and obesity, osteoporosis and even the immune system suggest the consumption of craft beer. However, more studies with more robust designs are required to obtain more generalizable and conclusive results. Finally, some challenges in the production of craft beer were detailed and some alternative solutions were mentioned.

Consumer Studies: Beyond Acceptability—A Case Study with Beer

Beer is one of the most consumed alcoholic beverages in the world; its consumption and preference are evolving from traditional industrial beers of low complexity to novel craft beers with diverse flavour profiles. In such a competitive industry and considering the complexity of consumer behaviour, improvement and innovation become necessary. Consequently, consumer science, which is responsible for identifying the motivation behind customer preferences through their attitudes, perception and behaviour, has implemented strategies ranging from simple hedonic measurements to several innovative and emerging methodologies for a deeper understanding of the variables that affect the product experience: sensory, affective and cognitive. In this context, we offer a review inspired by previous research that explores some of the quantitative and qualitative methods used in consumer studies related to beer consumption, ranging from traditional approaches (acceptability, purchase intention, preference, etc.) to techniques that go beyond acceptability and allow a different understanding of aspects of consumer perception and behaviour (segmentation, expectations, emotions, representation, etc.). Also, innovative applications (contexts, immersive technologies and virtual reality, implicit measures, etc.) and current trends related to consumer science (Internet, social media, pairing, product experience, etc.) are addressed.

Beyond Saccharomyces pastorianus for modern lager brews: Exploring non-cerevisiae Saccharomyces hybrids with heterotic maltotriose consumption and novel aroma profile

Non-domesticated, wild Saccharomyces yeasts have promising characteristics for beer diversification, particularly when used in the generation of de novo interspecific hybrids. A major motivation for the current work was the question whether attractive novel Saccharomyces interspecific hybrids can be created for the production of exotic lager beers without using the genomic resources of the ale yeast Saccharomyces cerevisiae. Importantly, maltotriose utilization is an essential characteristic typically associated with domesticated ale/lager brewing strains. A high-throughput screening on nearly 200 strains representing all eight species of the Saccharomyces genus was conducted. Three Saccharomyces mikatae strains were able to aerobically grow on maltotriose as the sole carbon source, a trait until recently unidentified for this species. Our screening also confirmed the recently reported maltotriose utilization of the S. jurei strain D5095T. Remarkably, de novo hybrids between a maltotriose-utilizing S. mikatae or S. jurei strain and the maltotriose-negative Saccharomyces eubayanus strain CBS 12357T displayed heterosis and outperformed both parents with regard to aerobically utilizing maltotriose as the sole source of carbon. Indeed, the maximum specific growth rates on this sugar were comparable to the well-known industrial strain, Saccharomyces pastorianus CBS 1513. In lager brewing settings (oxygen-limited), the new hybrids were able to ferment maltose, while maltotriose was not metabolized. Favorable fruity esters were produced, demonstrating that the novel hybrids have the potential to add to the diversity of lager brewing.

Screening and transcriptomic analysis of the ethanol-tolerant mutant Saccharomyces cerevisiae YN81 for high-gravity brewing

Ethanol stress is one of the major limiting factors for high-gravity brewing. Breeding of yeast strain with high ethanol tolerance, and revealing the ethanol tolerance mechanism of Saccharomyces cerevisiae is of great significance to the production of high-gravity beer. In this study, the mutant YN81 was obtained by ultraviolet-diethyl sulfate (UV-DES) cooperative mutagenesis from parental strain CS31 used in high-gravity craft beer brewing. The ethanol tolerance experiment results showed that cell growth and viability of YN81 were significantly greater than that of CS31 under ethanol stress. The ethanol tolerance mechanisms of YN81 were studied through observation of cell morphology, intracellular trehalose content, and transcriptomic analysis. Results from scanning electron microscope (SEM) showed alcohol toxicity caused significant changes in the cell morphology of CS31, while the cell morphology of YN81 changed slightly, indicating the cell morphology of CS31 got worse (the formation of hole and cell wrinkle). In addition, compared with ethanol-free stress, the trehalose content of YN81 and CS31 increased dramatically under ethanol stress, but there was no significant difference between YN81 and CS31, whether with or without ethanol stress. GO functional annotation analysis showed that under alcohol stress, the number of membrane-associated genes in YN81 was higher than that without alcohol stress, as well as CS31, while membrane-associated genes in YN81 were expressed more than CS31 under alcohol stress. KEGG functional enrichment analysis showed unsaturated fatty acid synthesis pathways and amino acid metabolic pathways were involved in ethanol tolerance of YN81. The mutant YN81 and its ethanol tolerance mechanism provide an optimal strain and theoretical basis for high-gravity craft beer brewing.

From Ground to Glass: Evaluation of Unique Barley Varieties for Craft Malting, Craft Brewing, and Consumer Sensory

Differentiating agricultural products has been adopted as a strategy to improve farm profitability and thereby business sustainability. This study aimed to evaluate unique barley varieties for craft malting and brewing markets to enhance profitability for diversified grain growers in southwestern Washington. Advanced barley breeding lines from Washington State University (WSU) were compared to a control variety (CDC-Copeland) through field trials, experimental and commercial malting conditions, and consumer sensory evaluation. The beers differed only by the genotype-dependent malt. Malting conditions (experimental or commercial) and field replicate influenced five out of the eight malt quality traits measured, while genotype influenced seven out of eight of the traits. Consumers differentiated the beers through ranking, open description, and check all that apply during a central location test. Based on consumer liking, breeding lines 12WA_120.14 or 12WA_120.17 could replace CDC-Copeland in beers. A total of 83% of consumers responded that they would pay more for a beer if it would support local farmers. This value proposition represents an opportunity for consumer purchasing to support producers, who form the foundation of the craft malt and beer value chain and whose economic success will determine the sustainability of small farms in minor growing regions. We provide further evidence for the contributions of barley genotype to beer flavor, while tracing the impact of barley genotype from ground to glass.

Doing Well by Creating Economic Value through Social Values among Craft Beer Breweries: A Case Study in Responsible Innovation and Growth

Social values are key to the sustainability of organizations. Drawing on value-based research, stakeholder theory, and corporate social responsibility research, this paper builds a case study of the interplay between social values, innovation, and economic growth. The craft beer industry is a fast-growing industry with a potential emphasis on social values built on small-scale production and localism. We examine how craft breweries attempt to resolve tensions derived from pursuing economic and social values simultaneously. As breweries continue to grow, owners face decisions of scale and growth, which may undermine a value-driven industry with close ties to the local community. Findings from six craft breweries, operating in Northern New England, USA, suggest a complex managerial dilemma involving (a) small-batch innovation for niche and mass production for growth, (b) responsible innovation for balancing local authenticity and geographical expansion, and (c) independent and business partnering. We further unpacked the tensions that operated at local and non-local levels.

Targeted and Nontargeted Metabolomics of Amino Acids and Bioactive Metabolites in Probiotic-Fermented Unhopped Beers Using Liquid Chromatography High-Resolution Mass Spectrometry

Beer is one of the most popular beverages in the world. The increased popularity of craft beers has led to the development of unique beers that are alcohol-free, gluten-free, low calorie, or with functional properties through fermentation with probiotic microorganisms. In this study, functional unhopped beers were evaluated by utilizing probiotics (Lacticaseibacillus paracasei Lpc-37 and ibSium Saccharomyces cerevisiae CNCM I-3856) as starter cultures. The metabolites produced by probiotics were investigated using a nontargeted metabolomics approach and identified against metabolomics databases (Kyoto Encyclopedia of Genes and Genomes (KEGG), Human Metabolome Database (HMDB), Yeast Metabolome Database (YMDB), METLIN tandem mass spectrometry (MS/MS)). Derivatives of branched-chain (leucine) and aromatic amino acids (phenylalanine, tryptophan, and tyrosine) were enriched (one-way analysis of variance (ANOVA) p < 0.05) in probiotic-fermented unhopped beers, especially tryptophan metabolites. In addition, the synergistic effects of yeast-lactic acid bacteria (LAB) interactions led to further enrichment of higher acids such as (S)-(-)-2-hydroxyisocaproic acid, phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid. The potential pathways for the formation of novel bioactive tryptophan metabolites (indole and indoleacrylic acid) by LAB were elucidated. Altogether, probiotic LAB-fermented unhopped beer showed the highest antioxidant capacity and total phenolic content. This work provides the basis for the discovery of bioactive metabolites in probiotic-fermented foods.

Biotechnological exploitation of Saccharomyces jurei and its hybrids in craft beer fermentation uncovers new aroma combinations

Hybridisation is an important evolutionary mechanism to bring about novel phenotypes and may produce new hybrids with advantageous combinations of traits of industrial importance. Within the Saccharomyces genus, Saccharomyces jurei is a newly discovered species and its biotechnological potential has not yet been fully explored. This yeast was found to be able to grow well in unhopped wort and at low temperatures, qualities necessary in good candidates for fermented bevarages. Here, we analysed its fermentation and aroma profile and created novel non-GMO hybrids between S. jurei and S. cerevisiae ale yeasts to develop new starter strains with interesting flavours for the craft brewing and beverage industry in general. Pilot beer fermentations with specific hybrids showed a good fermentation performance, similar to the ale parent strain, while eliminating the hyper-attenuation characteristic and a more complex flavour profile. This study exploits the genetic diversity of yeasts and shows how inter-specific hybridisation and clone selection can be effectively used in brewing to create new products and to eliminate or increase specific traits.

Effects of adding spices with antioxidants compounds in red ale style craft beer: A simplex-centroid mixture design approach

The growing demand for authentic products that provide sensory characteristics combined with health benefits has been the focus of current studies. This study developed a Red Ale style craft beer with spices such as turmeric (T), black pepper (P) and aroma hops (H), used isolated or in mixtures. A mixture design was employed to evaluate the total phenolic compounds and the antioxidant activity in the green and aged beers formulations. The spice extracts influenced the product's shelf-life. The addition of spices into the beers did not affect the physicochemical parameters that classify the Red Ale style, according to the hierarchical cluster analysis, except for aroma hops. A multiresponse optimization approach simultaneously maximized the antioxidant activity and the phenolic compounds in beers. The ideal formulation obtained for green beers was 25% T and 37.5% P and H; for aged beers, the formulation was 50% T, 20% P and 30% H.

Characterization and Discrimination of Commercial Portuguese Beers Based on Phenolic Composition and Antioxidant Capacity

Beer has been highly appreciated due to its phenolic composition and antioxidant capacity conjugated with its low alcohol content. Although some studies exist regarding the phenolic composition and antioxidant capacities of beers, there are no studies related to the determination of these parameters in the most commonly consumed commercial beers in Portugal. The phenolic composition and antioxidant capacity of 23 Portuguese commercial beers of different styles and types were studied for the first time. The total phenolic content, ortho-diphenols, and flavonoids ranged between 0.15 ± 0.01 and 0.82 ± 0.07 g Gallic Acid (GA) L⁻¹; 0.07 ± 0.02 and 1.80 ± 0.09 g GA L⁻¹, and 0.02 ± 0.00 and 0.15 ± 0.02 g Catechin (CAT) L⁻¹, respectively. An accurate quantitative phenolic analysis was also performed, and the compound identified with a higher amount was gallic acid, followed by syringic acid. Concerning flavonoids, gallo-catechin was the most abundant compound identified (from 21.44 ± 2.87 and 144.00 ± 10.93 μg mL⁻¹). A significant correlation between ortho-diphenols and the antiradical capacity (ABTS and DPPH) was found, the latter being negatively correlated. Flavonoids content was also positively correlated with total phenols and antiradical capacity determined by the ABTS assay. These results evidence that phenolic composition is affected by several factors inherent to beers, namely ingredients, fermentation type, and brewing process.

The attitude of Czech university students to beer consumption from microbreweries

The questionnaire survey was focused on the relation of university students of generation Z in the Czech Republic to beer from microbreweries. The survey involved 1,103 respondents from among Czech university students. 1,004 respondents complied with the survey conditions (they had to belong to university students and consume beer). Although 98% of beer consumed in the Czech Republic is from industrial breweries, it has turned out that the proportion of students who consume beer from industrial breweries and microbreweries is almost the same. As for beer from microbreweries, students prefer classic beers of the Pilsen type. So far, these do not circulate in beer tourism in larger quantities. The respondents agree that beer tourism will compete successfully with wine tourism. For beer tourism to develop successfully, microbreweries must also offer catering, accommodation, and other services; beer baths are in high demand at present. The economic benefits of microbreweries are in several areas – they integrate into tourist destinations, use local raw materials for beer and food preparation, create new jobs, enhance abandoned breweries and contribute to the development of rural areas.

Mycotoxins in artisanal beers: An overview of relevant aspects of the raw material, manufacturing steps and regulatory issues involved

The consumption of artisanal beer has increased worldwide. Artisanal beers can include malted or unmalted wheat, maize, rice and sorghum, in addition to the basic ingredients. These grains can be infected by toxigenic fungi in the field or during storage and mycotoxins can be produced if they find favorable conditions. Mycotoxins may not be eliminated throughout the beer brewing and be detected in the final product. In addition, modified mycotoxins may also be formed during beer brewing. This review compiles relevant information about mycotoxins produced by Aspergillus, Fusarium and Penicillium in raw material of artisanal beer, as well as updates information about the production and fate of mycotoxins during the beer brewing process. Findings highlight that malting conditions favor the production of mycotoxins by the fungi contaminating cereals. Therefore, good agricultural and postharvest mitigation strategies are the most effective options for preventing the growth of toxigenic fungi and the production of mycotoxins in cereals. However, the final concentration of mycotoxin in artisanal beer is difficult to predict as it depends on the initial concentration contained in the raw material and the processing conditions. The current lack of limits of mycotoxins in artisanal beer underestimates possible risks to human health. In addition, modified mycotoxins, not detected by conventional methods, may be formed in artisanal beers. Maximum tolerated limits for these contaminants must be urgently established based on scientific data about transfer of mycotoxins throughout the artisanal beer brewery process.

Craft beer: An overview

The purpose of the work was to provide an overview on craft beer. Details and issues concerning history and legal definition market, fiscal policy, innovation, safety, healthiness, consumer profile, and sustainability are supplied. The term "craft brewery" generally refers to a brewery able to produce low volumes of beer, often made with traditional ingredients-for emulating historic styles-but also with the addition of nontraditional ingredients as a distinctiveness sign of the master brewer. In many countries, the importance of the company size is related to the opportunity to take advantage of reduced excise rates for low production volumes. In several countries, another important requisite of a craft brewery is represented by its independence from other alcohol industry members. Even in the presence of a great heterogeneity of the size of craft breweries in the various countries, their number in the world is around 17,000. Craft beer is mainly consumed in restaurants and bars. Innovation of craft beer concerns aspects, such as ingredients, alcohol content, aging, and packaging, and the profile of the typical craft beer drinker is that of a young man, with a higher education and a medium-high income. Craft beers are often not filtered/not pasteurized and, for these reasons, they are beverages rich in health compounds but with a reduced shelf life. As in the case of larger breweries, the environmental impact of craft breweries is mainly represented by water consumption and production of liquid and solid wastes.

Multi-response approaches in product-focused investigations: Methodological variations across three case studies

Consumers' product experiences are increasingly uncovered using approaches that extend beyond acceptability and sensory perception. The present research is situated in this context and adopts a multi-response approach to jointly obtain attitudinal, conceptual, emotional, situational and/or sensorial evaluations. With the aim of greater methodological understanding, three case studies were conducted with samples in three product categories (fruit- and vegetable-based beverages (n = 10), seafood (n = 6) and chocolate (n = 7)) using consumers from New Zealand (n = 196), India (living in New Zealand) (n = 138) and China (n = 167), conducted in central location (CLT) or home-use test (HUT) settings. Showcasing this multi-response approach and demonstrating its versatility in product research is the main contribution of the research. Across the three case studies different combinations of response types and scaling formats were successfully used (including CATA (check-all-that-apply) questions, yes/no questions and rating scales), and it was also found that tasted foods and written stimuli (food names) served equally well as stimuli. The degree of liking or disliking for individual samples was a useful benchmark against which to interpret the other types of responses, and situational appropriateness, obtained as item-by-use (IBU) responses always contributed unique insights. Facial emoji to obtain product-emotion associations yielded less valuable insights than a conceptualisation task. As expected, and in accordance with the rationale for adopting a multi-response approach, the combination of response types yielded greater stimuli insights than would otherwise have been gained. This held for each of the three case studies and supported future applications using a multi-response approach that extends beyond many related initiatives by including four response types in each case study.