Abstracts

Please find below the abstracts from the current issue.
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Zinc recycling from hot spent grain: effective extraction with sour wort
Zink-Recycling aus Heißtrub: Effektive Extraktion mit Sauergut

Zinc is an essential trace element for yeast metabolism. It is abundant in malt but is lost during wort preparation. Measures previously recommended to increase the zinc content in the first wort are either ineffective, associated with disadvantages for wort quality, or not permitted under the German Purity Law. However, as this study shows, the recovery of immobilized zinc through extraction from hot spent grain using sour wort proves to be an effective and cost-efficient method for improving yeast vitality and fermentation performance.

Descriptors: Yeast metabolism, essential trace elements, immobilized zinc, zinc extraction
By Franz, V., Neugrodda, C., Becker, T., Mosch, N.
Source: BRAUWELT 16 2026 (166), 572-575

 

Insights into the aging characteristics of weat beers
Einblicke in das Alterungsverhalten von Weizenbieren

The aging behavior is a key quality issue, but one that has received little attention to date in top-fermented beers. Against this backdrop, 25 commercial wheat beers were aged under natural and accelerated conditions and evaluated both analytically and sensorily. The goal was to assess the impact of different matrices and process conditions (e.g., raw materials, technology) on the flavour instability of commercial beers.

Descriptors: Aroma profile, beer aging, aging indicators, top-fermented beer
By Lehnhardt, F., Schneiderbanger, H., Gastl, M.
Source: BRAUWELT 16 2026 (166), 576-578

 

Not just a supply for bitter compounds

Hops are an indispensable raw material for brewing beer and a medicinal plant with great potential. An increasing number of medical Research projects and innovations in hop products are opening up new opportunities for developing hop-based beverages with added health benefits and dietary supplements.

Descriptors: hops, pharmacological potential, bitter substances, hop fractions
By Schönberger, C.
Source: BRAUWELT International 4 2026 (44), 172-175

 

Studying the microflora in tunnel pasteurisers

Tunnel pasteurisers are an essential part of processes in the brewing and beverage industries. But the microbiological situation in these plants has received little attention. This three-part series of articles investigates the microflora in tunnel pasteurisers from a scientific and operational perspective. Part 1 summarises the microflora found, evaluates the effects and measures and categorises the microorganisms identified in terms of their risk to brewery products, thus providing insights for practical application.

Descriptors: pasteurization, microbiology, yeast, beer spoiling Bacteria
By Kunz, O., Gastl, M., Jacob, F., Zarnkow, M., Hutzler, M.
Source: BRAUWELT International 4 2026 (44), 202-205

 

Barley Koji: Exploring the Effects of Steeping and Fermentation on Malt Quality Parameters

Koji has long been used in Japan to supply enzymes, flavors, and nutrients for traditional fermented food and beverages. Its application to brewing offers a unique, versatile, and innovative alternative to specialty malts. This study assessed the brewing suitability of kilned barley koji produced with a barley-koji strain of Aspergillus oryzae—here termed barley koji malts (BKM)—by evaluating the effects of steeping times (6, 7, and 8 h) and solid-state fermentation (SSF) durations (40, 44, and 48 h) on malt quality and metabolomic profiles. BKM exhibited desirable malting quality parameters, including extract levels comparable to standard base malts, rapid production times, and high color formation under a base malt kilning profile. Shorter steeping times yielded improved enzymatic and technological performance, while variation in SSF duration produced distinct color development. This study demonstrates the potential of BKM as a versatile and innovative alternative for specialty malts in craft brewing applications.

Descriptors: Aspergillus oryzae, metabolomics, solid-state fermentation, specialty malts
By Brito, A. D. C. D., Silveira, P. T. D. S., Ulhmann, H., Schmidt, F. L., Sherman, J.
Source: Journal of the ASBC 3 2026 (84), 296-317, DOI: https://doi.org/10.1080/03610470.2025.2612314

 

Investigating the Regional Identity of Cascade and Mosaic® Hops in the Pacific Northwest Across Two Harvest Years

Regional identity is an important factor in hop production, particularly in the Pacific Northwest, where growing environment can impart economically valuable quality traits. Previous studies have documented regional effects on hop chemistry and aroma, but most have been limited to single harvest years, making it difficult to separate persistent regional signals from annual variability. Chemical and sensory properties of Cascade and Mosaic® hops grown at 35 locations across Oregon and Washington were evaluated over two consecutive harvest years (2020–2021). A total of 29 chemical and 14 sensory parameters were analyzed using multivariate and univariate statistics. For both varieties, chemical composition showed stronger and more consistent regional structuring than sensory aroma. Harvest year strongly influenced oxygenated terpenes, esters, and related sensory attributes, particularly in Cascade hops, resulting in substantial year-to-year variability within locations. Mosaic® hops exhibited greater chemical stability across years, with persistent regional differences primarily associated with hydrocarbon terpenes, total oil content, and hop storage index. Sensory differences were smaller and more variable than chemical differences. Overall, regional identity in hops persists across years but is modulated by annual environmental variation in a variety-dependent manner.

Descriptors: carrageenan, filterability, beer clarity, wort clarification, kettle finings, process optimisation
By Féchir, M., Shellhammer, T. H.
Source: Journal of the ASBC 3 2026 (84), 318-329, DOI: https://doi.org/10.1080/03610470.2026.2646405

 

Chemical and Sensory Evaluation of Smoke-Related Volatile Phenols in Hops and Beer

Wildfire smoke exposure has emerged as a growing quality concern for hops, yet its impact on beer aroma remains poorly defined. This study evaluated the influence of smoke-related volatile phenols (VPs) on beer quality using sensory thresholds, descriptive analysis, chemical quantification, and brewing trials. Orthonasal detection thresholds for five key VPs (guaiacol, 4-methyl guaiacol, and o-, m-, and p-cresol) ranged from 11 to 140 µg/L, while rejection thresholds varied widely. Cresols were rejected near detection thresholds, whereas guaiacol and 4-methyl guaiacol were tolerated at higher concentrations, indicating compound-specific sensory responses. Descriptive analysis showed guaiacol and 4-methyl guaiacol contributed smoky, woody, and occasionally pleasant attributes (e.g., sweet/vanilla, spice/clove, smoked meat, and BBQ), while cresols were associated with undesirable notes such as medicinal, chemical, Band-Aid, plastic, barnyard, and urine. Brewing trials using smoke-affected and non-affected Citra® and Mosaic® hops demonstrated that smoke-affected Mosaic® produced higher VP concentrations and stronger smoke-related sensory attributes than Citra®. Although smoke exposure to these hops was not controlled, compositional differences were sufficient to drive clear sensory outcomes. Notably, perceptible smoke aroma occurred even when individual odor activity values were below unity, highlighting limitations of OAV-based predictions. Extraction-rate analysis suggested brewing variables, including hopping regime and yeast, influence VP transfer and expression. Together, these results establish a foundational framework for interpreting smoke-derived volatile phenols in hops and beer and provide actionable insight for evaluating and managing wildfire smoke impacts in brewing applications.

Descriptors: Beer quality, detection threshold, hops, smoke
By Samia, R., Dailey, J., Williams, S., Pitra, T., Schilaty, T., Schultz, A., Cortés González, A., Alexander, J., Shellhammer, T. H.
Source: Journal of the ASBC 3 2026 (84), 330-341, DOI: https://doi.org/10.1080/03610470.2026.2652812

 

Insights into the Foaming Properties of Alcoholic and Non-Alcoholic Beers Using Four Different Foaming Methods

Although foam is an important quality parameter of beer, the foam of non-alcoholic beers (NABs) often fails to meet consumer expectations. Because scientific insight into the topic is lacking, this study investigated the differences in foaming properties between NABs and corresponding alcoholic beers (ABs), focusing on the underlying destabilisation mechanisms and associated physicochemical properties. The foam properties of 16 commercial beers were investigated using four foaming methods, including a novel method that allows for foam replenishment. By generating foams with varying (initial) volume, liquid content and lifespan, each test highlighted distinct destabilisation mechanisms and, when combined, offered a more complete understanding of foaming properties. The results confirm that NABs produced by dealcoholisation exhibit significantly reduced foam capacity and stability, resulting in a coarser foam structure compared to ABs. This instability was primarily attributed to a higher rate of coalescence, potentially driven by lower alcohol content and higher surface tension. NABs produced using alternative fermentation exhibited significantly better foam stability than those produced by dealcoholisation, highlighting the possible influence of the NAB production technique. This work provides fundamental knowlede necessary for brewers to create targeted strategies aimed at improving the foam quality of NABs.

Descriptors: capacity, foam coarsening, foaming methods, foam stability, non-alcoholic beer
By Bossaerts, L., Langenaeken, N. A., Wouters, A. G. B., Courtin, C. M.
Source: Journal of the ASBC 3 2026 (84), 355-371, DOI: https://doi.org/10.1080/03610470.2026.2652806

 

Effect of Carbonation on the Survival of Escherichia coli and Salmonella Enteritidis in Non-Alcoholic Beer and the Microbiological and Physicochemical Quality of Draught Products

This study investigated the microbiological quality of non-alcoholic draught beers and examined the effect of carbonation on the survival of pathogens, specifically Escherichia coli O157 and Salmonella enterica subsp. enterica serovar Enteritidis. Samples of non-alcoholic draught beers were collected from various outlets across the United Kingdom, while additional data from non-UK beers (United States, Belgium and Spain) were provided by an independent global brewery. One fully carbonated non-alcoholic beer (2.8 v/v) along with its decarbonated variants 1.9, 1.2, 1.0, 0.8 and 0.1 (v/v) were evaluated. Both carbonated and decarbonated versions were tested with and without the addition of sugars (1 g/100 mL of maltose and 0.25 g/100 mL of lactose). Beers were inoculated with three strains of E. coli O157 and Salmonella Enteritidis, and growth and survival were monitored over six months at five time points, in triplicate. Analytical results indicated that the alcohol content in four out of the 90 beers slightly exceeded the regulatory threshold of 0.5% v/v. Overall, 83% of samples tested were classified as microbiologically good or acceptable, while 17% exhibited poor quality, with total aerobic counts exceeding 10,000 CFU/mL. Challenge testing demonstrated that both E. coli and Salmonella were inactivated in fully carbonated beers but were capable of growth in decarbonated and low-carbonated beers. Furthermore, the addition of sugar enhanced survivalof the tested pathogens at specific carbonation levels but increased growth was not observed.

Descriptors: Beer, carbonation, draught beer, microbial safety, NAB, non-alcoholic beer, pathogens
By Rachon, G., Foxall, A., Mundzik, P., Swiatkowska, W., Shimokawa, M., Britton, S. J.
Source: Journal of the ASBC 3 2026 (84), 372-381, DOI: https://doi.org/10.1080/03610470.2026.2658895

 

Identification, Traceability and Control of Butyric Acid Off-Flavor in Beer

Butyric acid contamination, typically characterized by distinct cheesy or sewage-like odor notes, is a common quality defect in beer. However, the flavor-active compounds causing this defect, their sources and dynamic changes, have not been fully elucidated. In this study, sensory evaluation, gas chromatography-mass spectrometry analysis, and high-throughput genomic sequencing were integrated to provide a comprehensive characterization of the compounds contributing to butyric acid off-flavor in beer and to identify their sources. The results revealed that butyric acid, isovaleric acid, and acetic acid were the primary flavor-active compounds. Clostridium and Bacillus were identified as the dominant bacterial genera, and notably, Clostridium_sensu_stricto was detected for the first time in wort filtration systems and syrup tank rinse water. The wort filtration system, syrup tank, and associated piping networks were determined to be critical control points for butyric acid contamination. Consequently, rigorous sanitation measures and enhanced microbial monitoring in these high-risk areas should be implemented. This study provides a robust theoretical foundation for tracing and preventing butyric acid contamination in the beer industry.

Descriptors: Beer, butyric acid, clostridium spp, high-throughput genomic sequencing, microbial prevention, volatile flavor compounds
By Yang, Q., Chen, S., Chen, J., Liang, N., Chen, M., Liang, J., Tu, J., Hao, J.
Source: Journal of the ASBC 3 2026 (84), 382-392, DOI: https://doi.org/10.1080/03610470.2026.2646400

 

Thiol groups are determinant for overcoming acetic acid and pH stress in wine and beer fermentation-derived Saccharomyces cerevisiae strains

Acetic acid (AA), a natural by-product of ethanol fermentation in yeast cells, is widely present in lignocellulosic hydrolysate as a fermentation inhibitor. Thus, gaining insight into the molecular mechanisms of AA tolerance in yeast is particularly relevant for industrial applications. This study investigates the response to AA stress in two Saccharomyces cerevisiae strains (ATCC 9804 and ATCC 13007) during different metabolic states (fermentation, respiro-fermentation, and respiration) and external pH levels (3․0 and 4.5). The results show that AA reduces the viability of both strains in a dosage-dependent manner. Moreover, ATCC 13007 is more sensitive to AA stress compared to ATCC 9804. Respiratory metabolism and higher pH correlate with better resistance to AA stress. Catalase activity was observed to increase by 1.5–6-fold under AA stress conditions, in accordance with changes in yeast thiol group content and growth. The influence of AA stress is reactive oxygen species-dependent, and redox balance regulation was found to increase the robustness of S. cerevisiae ATCC 13007 to AA by 2-fold. The study reveals valuable insights into yeast adaptation to stress conditions, contributing to the development of robust yeast strain construction for high-yield biomass and chemicals production.

Descriptors: acetic acid, yeast acid stress, redox balance, metabolism, carbon-source, fermentation, respiration
By Shirvanyan, A., Primavera, A., Guaragnella, N., Ledesma-Amaro, R., Trchounian, K.
Source: FEMS Yeast Research 2026 (26), DOI: https://doi.org/10.1093/femsyr/foag004

 

Carbonation of beer in microbreweries using a bulk gas-to-atomised liquid (BGAL) approach

Why was the work done: In microbreweries, forced carbonation in a bright beer tank using a carbonation stone may require up to 72 hours to reach specification for dissolved carbon dioxide. The mass transfer kinetics in bubbled systems are generally poor due to the small surface area-to-volume ratio in the liquid phase. Alternatively, droplets of beer have a comparatively large surface area-to-volume ratio and can absorb gas at greater rates. How was the work done: A bulk gas-to-atomised liquid (BGAL) process was evaluated for beer carbonation. Using this method, a spray of beer droplets is carbonated in a closed vessel pressurised with carbon dioxide gas and equipped with a nozzle to atomise the beer. Following testing at prototype scale (3 x 19 L), the approach was evaluated at a pilot scale by retrofitting a 240 L bright beer tank to accommodate a nozzle, and a laboratory brewed IPA was carbonated at a rate of 3.0 L/min. What are the main findings: The rate of carbonation achieved by the BGAL system was between 3 and 50 times greater than conventional carbonation, the precise improvement was dependent upon the operating conditions for the conventional method. Further, analysis of the finished beer revealed that hop oil compounds in BGAL carbonated beer were statistically similar to the concentration in beer carbonated by conventional means. Why is the work important: These results suggest that the BGAL system could enhance the carbonation step in microbreweries that use a carbonation stone in bright beer tank, while maintaining the aromatic characteristics of the beer.

Descriptors: carbonation, process intensification, bulk gas-to-atomised liquid, hop oil compounds
By Jean, A., Funkhouser, J., Makowsk, A., Groene, S., Brown, R.
Source: Journal of the Institute of Brewing 2 2026 (132), 62-77, DOI: https://doi.org/10.58430/jib.v132i2.98

 

PFAS in the Brewing Chain: Occurrence in Raw Water and Beer – A Pilot Study

This pilot study investigates the occurrence of per- and polyfluoroalkyl substances (PFAS) in raw water used for brewing and in beer produced from this water in the Czech Republic. A total of 17 raw water samples and 21 beer samples from different breweries were analyzed. The determination of 32 target PFAS compounds was performed using ultrahigh performance chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), following solid-phase extraction (SPE) for water samples and organic solvent extraction followed by dispersive SPE (d-SPE) for beer samples. PFAS were detected in the majority of raw water samples at low concentration levels, typically in the range of a few ng/L, well below the regulatory limit for the sum of PFAS (100 ng/L) in drinking waters established by EU Directive 2020/2184. In beer samples, no PFAS were quantified above the method quantification limits. These results indicate that PFAS are commonly present in water sources used in brewing; however, under the conditions of this study, their transfer into the final product was not demonstrated. The study highlights the need for an analytical method with sufficiently low LOQs to detect even trace levels of PFAS in beer. At the same time the results indicate that no significant PFAS contamination of beer was detected during the brewing process from other raw materials or from the technological processes.

Descriptors: PFAS, raw water, beer, UHPLC-MS/MS
By Dvořáková, D., Pernica, M., Svobodová, V., Pulkrabová, J., Běláková, S.
Source: Kvasny Prumysl 3 2026 (72), 1207-1214, DOI: https://doi.org/10.18832/kp2026.72.1207