Increasing Higher Alcohols and Acetates in Low-Alcohol Beer by Proteases.

The market of non-alcoholic and low-alcohol beer has grown continuously thanks to the advocacy for healthy and responsible drinking. Non-alcoholic and low-alcohol products usually possess less higher alcohols and acetates and more aldehyde off-flavors due to the manufacturing processes. The employment of non-conventional yeasts partially mitigates this problem. In this study, we used proteases to optimize the wort amino acid profile for better aroma production during yeast fermentation. The design of experiments was applied to increase the leucine molar fraction, aiming to boost 3-methylbutan-1-ol and 3-methylbutyl acetate (banana-like aromas). This led to an increase from 7% to 11% leucine in wort after protease treatment. The aroma output in the subsequent fermentation, however, was yeast-dependent. An 87% increase of 3-methylbutan-1-ol and a 64% increase of 3-methylbutyl acetate were observed when Saccharomycodes ludwigii was used. When Pichia kluyveri was employed, higher alcohols and esters from valine and isoleucine were increased: 58% more of 2-methylpropyl acetate, 67% more of 2-methylbutan-1-ol, and 24% more of 2-methylbutyl acetate were observed. Conversely, 3-methylbutan-1-ol decreased by 58% and 3-methylbutyl acetate largely remained the same. Apart from these, the amounts of aldehyde intermediates were increased to a varying extent. The impact of such increases in aromas and off-flavors on the perception of low-alcohol beer remains to be evaluated by sensory analysis in future studies.

Sourdough cultures as reservoirs of maltose-negative yeasts for low-alcohol beer brewing.

De novo sourdough cultures were here assessed for their potential as sources of yeast strains for low-alcohol beer brewing. NGS analysis revealed an abundance of ascomycete yeasts, with some influence of grain type on fungal community composition. Ten different ascomycete yeast species were isolated from different sourdough types (including wheat, rye, and barley) and seven of these were screened for a number of brewing-relevant phenotypes. All seven were maltose-negative and produced less than 1% (v/v) alcohol from a 12 °Plato wort in initial fermentation trials. Strains were further screened for their bioflavouring potential (production of volatile aromas and phenolic notes, reduction of wort aldehydes), stress tolerance (temperature extremes, osmotic stress and ethanol tolerance) and flocculence. Based on these criteria, two species (Kazachstania servazzii and Pichia fermentans) were selected for 10 L-scale fermentation trials and sensory analysis of beers. The latter species was considered particularly suitable for production of low-alcohol wheat beers due to its production of the spice/clove aroma 4-vinylguaiacol, while the former showed potential for lager-style beers due to its clean flavour profile and tolerance to low temperature conditions.

Influence of the dealcoholisation by osmotic distillation on the sensory properties of different beer types.

A comparative study was performed to better understand the feasibility of osmotic distillation as a process to produce a low-alcohol beer. Four diverse commercial beers styles were considered. The regular and corresponding dealcoholised beers were compared. The quality attributes and the volatile compounds loss after the dealcoholisation were checked. The work focused on the sensory properties of the obtained samples. A trained panel evaluated how the chosen sensory descriptors were influenced by the treatment. The results of quality attributes and volatile compounds were in line with works previously published by the authors. Interestingly, the results highlighted that beer characterized by malty character is more suitable than pale lager to be dealcoholised by the osmotic distillation process. The low alcohol milk stout and stout flavour profile, especially in terms of taste, was like the corresponding regular beer. Osmotic distillation was demonstrated to be a feasible process to produce low-alcohol beer.

Mrakia gelida in brewing process: An innovative production of low alcohol beer using a psychrophilic yeast strain.

Due to the increasing consumer demand, the production of low alcoholic and non alcoholic beer is the new goal of the present brewing producers. Although the beer with reduced alcohol content is currently obtained by physical methods, the use of non-Saccharomyces yeast, with low fermentations capacities, may represent an interesting biological approach. In this study the ethanol content and the volatile profile of a beer obtained using the basidiomycetous psychrophilic yeast strain Mrakia gelida DBVPG 5952 was compared with that produced by a commercial starter for low alcohol beers, Saccharomycodes ludwigii WSL17. The two beers were characterized by a low alcohol content (1.40% and 1.32% v/v) and by a low diacetyl production (5.04 and 5.20 µg/L). However, the organoleptic characteristics of the beer obtained using M. gelida are more appreciated by the panelists, in comparison to the analogous produced with the commercial strain of S. ludwigii.

Electrostatic Fermentation: Molecular Response Insights for Tailored Beer Production.

Electrostatic fermentation avoids the cellular redox imbalance of traditional fermentation, but knowledge gaps exist. This study explores the impact of electrostatic fermentation on the growth, volatile profile, and genetic response of Saccharomyces pastorianus Saflager S-23. The applied voltage (15 and 30 V) in the electrostatic fermentation system increased the growth and substrate utilization of S. pastorianus while decreasing ethanol production. The aromas typically associated with traditional fermentation, such as alcoholic, grape, apple, and sweet notes, were diminished, while aromas like roses, fruits, flowers, and bananas were augmented in electrostatic fermentation. RNA-seq analysis revealed upregulation of genes involved in cell wall structure, oxidoreductase activity, and iron ion binding, while genes associated with protein synthesis, growth control, homeostasis, and membrane function were downregulated under the influence of applied voltage. The electrostatic fermentation system modulates genetic responses and metabolic pathways in yeast, rendering it a promising method for tailored beer production. Demonstrating feasibility under industrial-scale and realistic conditions is crucial for advancing towards commercialization.

Brewing potential of strains of the boreal wild yeast Mrakia gelida.

Demand for low- or non-alcoholic beers has been growing in recent years. Thus, research is increasingly focusing on non-Saccharomyces species that typically are only able to consume the simple sugars in wort, and therefore have a limited production of alcohol. In this project, new species and strains of non-conventional yeasts were sampled and identified from Finnish forest environments. From this wild yeast collection, a number of Mrakia gelida strains were selected for small-scale fermentation tests and compared with a reference strain, the low-alcohol brewing yeast Saccharomycodes ludwigii. All the M. gelida strains were able to produce beer with an average of 0.7% alcohol, similar to the control strain. One M. gelida strain showing the most promising combination of good fermentation profile and production of desirable flavor active compounds was selected for pilot-scale (40 L) fermentation. The beers produced were matured, filtered, carbonated, and bottled. The bottled beers were then directed for in-house evaluation, and further analyzed for sensory profiles. The beers produced contained 0.6% Alcohol by volume (ABV). According to the sensory analysis, the beers were comparable to those produced by S. ludwigii, and contained detectable fruit notes (banana and plum). No distinct off-flavors were noted. A comprehensive analysis of M. gelida's resistance to temperature extremes, disinfectant, common preservatives, and antifungal agents would suggest that the strains pose little risk to either process hygiene or occupational safety.

Experimental Study and Modeling of Beer Dealcoholization via Reverse Osmosis.

The goals of the present investigation are to study and to model pale lager beer dealcoholization via reverse osmosis (RO). Samples were dealcoholized at a temperature of 15 ± 1 °C. An Alfa Laval RO99 membrane with a 0.05 m2 surface was used. The flux values were measured during the separations. The ethanol content, extract content, bitterness, color, pH, turbidity, and dynamic viscosity of beer and permeate samples were measured. The initial flux values were determined using linear regression. The initial ethanol flux (JEtOH 0) values were calculated from the initial flux values and the ethanol content values. A 2P full factorial experimental design was applied, and the factors were as follows: transmembrane pressure (TMP): 10, 20, 30 bar; retentate flow rate (Q): 120, 180, 240 L/h; JEtOH 0 was considered as the response. The effect sizes of the significant parameters were calculated. The global maximum of the objective function was found using a self-developed Grid Search code. The changes in the analytical parameters were appropriate. The TMP had a significant effect, while the Q had no significant effect on the JEtOH 0. The effect size of the TMP was 1.20. The optimal value of the factor amounted to TMP = 30 bar. The predicted JEtOH 0 under the above conditions was 121.965 g/m2 h.

Species and temperature-dependent fermentative aptitudes of Mrakia genus for innovative brewing.

The use of non-conventional brewing yeasts as alternative starters is a very promising approach which received increasing attention from worldwide scientists and brewers. Despite the feasible application of non-conventional yeasts in brewing processes, their regulations and safety assessment by the European Food Safety Authority still represent a bottlenecked hampering their commercial release, at least into EU market. Thus, research on yeast physiology, accurate taxonomic species identification and safety concerns associated with the use of non-conventional yeasts in food chains is needed to develop novel healthier and safer beers. Currently, most of the documented brewing applications catalysed by non-conventional yeasts are associated to ascomycetous yeasts, while little is known about analogous uses of basidiomycetous taxa. Therefore, in order to extend the phenotypic diversity of basidiomycetous brewing yeasts the aim of this investigation is to check the fermentation aptitudes of thirteen Mrakia species in relation to their taxonomic position within the genus Mrakia. The volatile profile, ethanol content and sugar consumption were compared with that produced by a commercial starter for low alcohol beers, namely Saccharomycodes ludwigii WSL 17. The phylogeny of Mrakia genus showed three clusters that clearly exhibited different fermentation aptitudes. Members of M. gelida cluster showed a superior aptitude to produce ethanol, higher alcohols, esters and sugars conversion compared to the members of M. cryoconiti and M. aquatica clusters. Among M. gelida cluster, the strain M. blollopis DBVPG 4974 exhibited a medium flocculation profile, a high tolerance to ethanol and to iso-α-acids, and a considerable production of lactic and acetic acids, and glycerol. In addition, an inverse relationship between fermentative performances and incubation temperature is also displayed by this strain. Possible speculations on the association between the cold adaptation exhibited by M. blollopis DBVPG 4974 and the release of ethanol in the intracellular matrix and in the bordering environment are presented.

Beer fermentation performance and sugar uptake of Saccharomycopsis fibuligera-A novel option for low-alcohol beer.

There is a growing trend for beers with novel flavor profiles, as consumers demand a more diversified product range. Such beers can be produced by using non-Saccharomyces yeasts. The yeast species Saccharomycopsis fibuligera is known to produce exceptionally pleasant plum and berry flavors during brewer's wort fermentation while its mycelia growth is most likely a technological challenge in industrial-scale brewing. To better understand and optimize the physiological properties of this yeast species during the brewing process, maltose and maltotriose uptake activity trials were performed. These revealed the existence of active transmembrane transporters for maltose in addition to the known extracellular amylase system. Furthermore, a single cell isolate of S. fibuligera was cultured, which showed significantly less mycelial growth during propagation and fermentation compared to the mother culture and would therefore be much more suitable for application on an industrial scale due to its better flocculation and clarification properties. Genetic differences between the two cultures could not be detected in a (GTG)5 rep-PCR fingerprint and there was hardly any difference in the fermentation process, sugar utilization and flavor profiles of the beers. Accordingly, the characteristic plum and berry flavor could also be perceived by using the culture from the single cell isolate, which was complemented by a dried fruit flavor. A fermentation temperature of 20°C at an original gravity of 10 °P proved to be optimal for producing a low-alcohol beer at around 0.8% (v/v) by applying the S. fibuligera yeast culture from the single cell isolate.

Representations of Low(er) Alcohol (Craft) Beer in the United States.

Given increasing social interest in health and wellness, rising cultural trends toward sobriety and moderating alcohol intake, and improvements in brewing technology, low(er) alcohol beer is a rising segment in the beer industry for both craft and larger-scale producers. In this paper, we assess the representation of low(er) alcohol beer among craft brewers in the United States. Using a novel quantitatively-informed qualitative analytical approach, we surveyed a randomized, non-representative sample of 400 craft brewery websites in the United States to assess the relative presence of low(er) alcohol beers as well as how these brews are represented by the breweries themselves. To do so, we recorded, both numerically and via website screenshots, the lowest ABV beverage on offer and noted the beer type, the beer name, and the ABV. Ales were the most prominent style of beer on offer, accounting for 62% of the low(er) ABV beers identified. Only 15.5% of the breweries surveyed in this study offered a beer with an ABV of less than 4%; however, an additional 67.9% offered a beer with an ABV of less than 5%. The representations of these low(er) alcohol products focused mostly on taste, health, and demographic indicators.

Is Buying and Drinking Zero and Low Alcohol Beer a Higher Socio-Economic Phenomenon? Analysis of British Survey Data, 2015-2018 and Household Purchase Data 2015-2020.

Zero and low alcohol products, particularly beer, are gaining consideration as a method to reduce consumption of ethanol. We do not know if this approach is likely to increase or decrease health inequalities. The aim of the study was to determine if the purchase and consumption of zero and low alcohol beers differs by demographic and socio-economic characteristics of consumers. Based on British household purchase data from 79,411 households and on British survey data of more than 104,635 adult (18+) respondents, we estimated the likelihood of buying and drinking zero (ABV = 0.0%) and low alcohol (ABV > 0.0% and ≤ 3.5%) beer by a range of socio-demographic characteristics. We found that buying and consuming zero alcohol beer is much more likely to occur in younger age groups, in more affluent households, and in those with higher social grades, with gaps in buying zero alcohol beer between households in higher and lower social grades widening between 2015 and 2020. Buying and drinking low alcohol beer had less consistent relationships with socio-demographic characteristics, but was strongly driven by households that normally buy and drink the most alcohol. Common to many health-related behaviours, it seems that it is the more affluent that lead the way in choosing zero or low alcohol products. Whilst the increased availability of zero and low alcohol products might be a useful tool to reduce overall ethanol consumption in the more socially advantageous part of society, it may be less beneficial for the rest of the population. Other evidence-based alcohol policy measures that lessen health inequalities, need to go hand-in-hand with those promoting the uptake of zero and low alcohol beer.

Drinking Behavior, Taste Preferences and Special Beer Perception among Romanian University Students: A Qualitative Assessment Research.

The transition from adolescence to adulthood can be a challenging period for many students. This period is associated with an increase in alcohol consumption (AC) which can develop a drinking behavior or shape the preferences for certain alcoholic beverages. The purpose of this study was to analyze the AC pattern among Romanian university students, by investigating the association between taste and consumption, including preferences for special beer. A 30-item omnibus-type questionnaire was distributed to undergraduate students and used to gather sociodemographic data, alcohol expectancies, drinking motives and consequences, and special beer consumption. Results showed a statistically significant relationship between the age of first alcohol use and the existence of an alcoholic family member. The main reasons for AC are taste, sensation, relaxation, and socialization. Both female and male students tend to drink occasionally, with a preference for public places. Female students prefer a sweet taste, choosing special beers over the regular ones. The students' residence may also influence the choice of special beers. Understanding the students' drinking behavior and taste preferences is essential to create useful strategies to discourage excessive AC. Special beer, a growing segment in the beverage industry, could represent a healthier and safety alternative to AC.

Impact of price promotion, price, and minimum unit price on household purchases of low and no alcohol beers and ciders: Descriptive analyses and interrupted time series analysis of purchase data from 70, 303 British households, 2015-2018 and first half of 2020.

BACKGROUND: The introduction of lower strength alcohol products results in less absolute alcohol purchased. This paper estimates the potential impact of price in shifting British household purchases from higher to lower strength beers and ciders. METHODS: Descriptive statistics and controlled interrupted time series analyses using Kantar Worldpanel's British household purchase data from 70,303 households during 2015-2018 and the first half of 2020. FINDINGS: No and low-alcohol products were less likely to be on price promotion than higher strength products. No and low-alcohol beers were cheaper per volume than higher strength beers; the reverse was the case for ciders. With the exception of low strength ciders (which had very few purchases) a higher volume was purchased when the product was on price promotion than when not. Again, with the exception of low strength ciders, the cheaper the cost, the greater the volume of purchase, more so when the product was on price promotion. The introduction of minimum unit price in Scotland (when controlling for changes in Northern England) and in Wales (when controlling for changes in Western England) shifted purchases from higher to lower strength products, more so for ciders than beers. In relative terms, the alcohol by volume of beer dropped by 2% and of cider by 7%. Changes did not differ by household income or the age of the main shopper. INTERPRETATION: There are opportunities for governments and alcohol producers and retailers to facilitate shifts of purchases from higher to lower alcohol strength products. Alcohol producers and retailers can ensure that the price of lower strength products is competitive vis a vis higher strength products. Governments can introduce minimum unit prices for the sale of alcohol, as has been done in Scotland and Wales. FUNDING: No funding was received for this study.

Effects of Operating Conditions during Low-Alcohol Beer Production by Osmotic Distillation.

Osmotic distillation (OD) is a membrane technology most commonly used for liquid concentration, but recently there has been an increased interest in ethanol removal from alcoholic beverages. The aim of this paper is to investigate the effect of the variation of some operating conditions (temperature, flow rate, type and amount of stripping solution), specifically in regard to the effect on quality and sensory properties of the dealcoholized beers. The results indicated that temperature and flow rate variation showed no significant effect, whereas stripping solution variation had substantial effects mainly in terms of the ethanol removed. A cost appraisal showed that the operating costs were high mainly because of the cost of the stripping water. However, it is important to consider the final stripping solution, which is slightly alcoholic and enriched in flavor. For this reason, it could be reused in the manufacture of beverages, for instance as high gravity beer dilution water.