The flavor characteristics of Baijiu, including differences in volatile organic compounds (VOCs) and sensory evaluation, are critical for determining its quality grade, which is also influenced by the fermentation time of the grains. However, the fermentation mechanisms of most types of Baijiu remain unclear. In this study, we investigated the flavor characteristics of three quality grades of Jinyu-wan Fuxiang Baijiu (JFXB) at two different fermentation times. A high number of VOCs were revealed via two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS), while principal component analysis (PCA) and orthogonal partial least squares discrimination analyses (OPLS-DA) indicated significant VOC differences among samples. Relative odor activity value (ROAV) assessment identified 12 VOCs with ROAV > 1 that were regarded as the key aroma contributors, along with 31 key differential VOCs with variable importance in projection (VIP) values greater than 1 (VIP > 1). Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) accurately identified 62 VOCs, establishing a VOC fingerprint and revealing 21 VOCs with VIP > 1. Sensory analysis revealed significant differences in the aroma, taste, and appearance of the samples. Overall, this study elucidates the flavor characteristics of Fuxiang Baijiu (FXB), providing valuable insights for the flavor quality control of FXB and a foundation for its fermentation process.

Hop creep has been primarily attributed to dextrin-degrading enzymes that generate fermentable sugars during dry hopping. However, hops also contain plant secondary metabolites conjugated to sugars that may represent an additional source of fermentable carbohydrate. In this study, free and enzymatically releasable sugars were quantified across sixteen commercial hop products using a modified methanol:chloroform:water extraction followed by enzymatic hydrolysis with a broad-spectrum glucosidase preparation. Glucose and fructose concentrations were determined using a colorimetric assay. Multi-factor ANOVA revealed significant effects of treatment, product type, and hop variety (p < 0.001), with a significant treatment × product interaction (p < 0.05). Enzymatic hydrolysis increased measurable glucose by statistically significant quantities relative to the free sugar fraction. Among product types, T90 hops exhibited the greatest total sugar concentrations, followed by Noble and Cryo products. Varietal differences were observed but were less pronounced than processing-type effects. These findings demonstrate that hops contain a pool of glycosidically bound sugars capable of being liberated by enzymatic or acid hydrolysis and therefore contribute to the fermentable matrix potentially driving hop creep. Recognition of these bound carbohydrates expands the mechanistic understanding of hop creep beyond dextrin hydrolysis and suggests a broader, multi-stage definition encompassing enzymes and plant secondary metabolite–derived sugars.

The hop bitter compound profiles of beer vary greatly in complexity. While in fresh lager/pilsner beers the bitterness is mainly attributed to iso-α-acids, the bitter flavor of aged lager/pilsner beers might be influenced by the formation of iso-α-acids degradation or cyclization products. The hop bitter compound profile of dry-hopped beer includes significant levels of humulones, lupulones, humulinones, hulupones, as well as xanthohumol, isoxanthohumol, and other minor hop resin compounds. This work presents the usage of ultra high-pressure liquid chromatography coupled to quadrupole time-of-flight quadrupole mass spectrometry (UPLC-Q-ToF) for quantification of major hop bitter compounds and non-targeted analysis for other hop bitter compounds that may contribute to the hop bitter profile of beer. The UPLC-Q-ToF quantification method showed excellent results in method validation and high comparability to the LC-based industry standard methods (EBC 9.47 and EBC 9.50) and was suitable to show differences in concentrations of major hop bitter compounds for lager/pilsner and dry-hopped beers. Non-targeted analysis, using UPLC-Q-ToF, was able to tentatively identify other hop bitter compounds that drive separation of fresh vs. aged dry-hopped samples.

No- and low- alcohol beers (NABLABs) lack ethanol, an important preservative that helps prevent contamination with microbial pathogens. This study used a loop-mediated isothermal amplification (LAMP) assay to detect pathogens in beer. We applied the assay to five Salmonella serovars, three E. coli strains, and two Listeria monocytogenes strains in three styles of alcohol-free beer (lager, pale ale, and stout). The assay detected all pathogens tested in all the beer styles in less than 45 min. The assay itself was designed to be simple to perform, without the requirement for extensive training or complicated laboratory equipment. When testing was performed by local brewers in a blind trial, they were able to perform the assay competently and their results matched the anticipated results. Limits of detections were typically between 101–103 cfu/mL with better sensitivity for the Gram-negative pathogens. The sensitivity of the assay might be improved further with the incorporation of a pre-enrichment step.

Evaporative deposition patterns of droplets have been used to identify chemical differences in spirits, but similar studies on mezcal remain unexplored. Traditional spectroscopic methods offer accurate chemical fingerprinting for mezcal aging and authenticity. However, they require costly instrumentation and complex calibration, which limits their use in rapid field screening. This work aims to evaluate whether dark-field microscopy images of evaporated mezcal droplets can distinguish between young (unaged) and barrel-aged (≥12 months) samples. The study addresses the gap in low-cost, image-based approaches for mezcal quality control. Mezcal samples from Agave salmiana were diluted to 20% alcohol by volume (ABV), deposited as 1 μL droplets on glass slides, and allowed to evaporate under ambient conditions. Resulting patterns were imaged using dark-field microscopy. Principal component analysis (PCA) was applied for dimensionality reduction, and a support vector machine (SVM) classifier was trained and validated on 201 images. The SVM model achieved an overall accuracy of 0.80, a sensitivity of 0.80, and a specificity of 0.81. The receiver operating characteristic (ROC) curve yielded an AUC of 0.90, indicating strong discriminative ability between young and aged mezcal based on droplet patterns. In summary, evaporative pattern analysis, combined with PCA–SVM classification, demonstrates a viable and low-cost alternative for verifying mezcal aging. While less chemically interpretable than spectroscopy, this approach offers operational simplicity and scalability for small producers. Future work should expand datasets, explore deep learning models, and integrate imaging with spectroscopic methods for multimodal authentication systems.

Non-alcoholic (NA) beer (<0.5% ABV) can support the survival of foodborne pathogens such as Salmonella. Typical recommendations for NA beer pasteurization (73.9 °C for 1 min or 80–120 PU) can help ensure food safety, but producers do prefer lower temperatures to preserve product quality. This study evaluated the impact of a lower heat treatment (52 °C for 1 min; ∼0.75 PU) on the survival of Salmonella enterica subsp. enterica serovar Tennessee in NA beer over six months and assessed the impact of co-inoculation with a spoilage organism, Levilactobacillus brevis. NA beer was inoculated with S. Tennessee (∼8.0 log CFU/mL) only or co-inoculated with L. brevis (∼8.0 log CFU/mL) and subjected to three pasteurization treatments: typical (73.9 °C for 1 min), low (52 °C for 1 min), and no pasteurization. Samples were stored at 14 °C and analyzed over six months. Significant differences were observed between pasteurization treatments post-pasteurization where Salmonella populations in the Salmonella-only samples reduced by 8.07 ± 0.00, and 2.25 ± 0.13 log CFU/mL for the typical and low samples, respectively. Similarly, post-pasteurization Salmonella populations in the co-inoculated samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the typical, low, and no pasteurization samples, respectively. After 183 days, Salmonella persisted in the low and no pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that Salmonella can survive for at least 183 days in NA beer under low pasteurization conditions and can survive despite the presence of a common spoilage organism.

Lipids, though often overlooked in brewing due to their low concentrations in finished beer, play a significant role in beer production and quality. This review explores the diverse impact of lipids across malting, brewing, and fermentation, including their influence on yeast metabolism, foam stability, flavor development, and beer oxidation. Lipids comprise essential nutrients to yeast but can also introduce challenges such as haze formation and flavor instability. Their role in foam collapse, influenced by lipid-binding proteins and oxidation processes, is examined in detail. Additionally, strategies for managing lipid oxidation and improving beer stability are discussed, providing brewers with insights to optimize product quality.

The biotransformation and release of polyfunctional thiols (PFTs), including 3-sulfanylhexan-1-ol (3SH), 4-methyl-4-sulfanylpentan-2-one (4MSP), and 3-sulfanyl-4-methylpentan-1-ol (3S4MP), contribute to tropical fruit aromas in beer. This study examines the effect of fermentation temperature (15–30 °C) on PFT production across five commercial yeast strains. Pilot-scale beers were brewed with Cascade hops and analyzed for 29 aroma compounds. A strong temperature-dependent increase in 3SH (33–72%) was observed, with the lager yeast strain yielding the highest levels at the high-temperature condition (30 °C). However, sensory analysis indicated that elevated thiol concentrations alone did not enhance tropical aroma. Instead, increased levels of β-ionone, β-damascenone, acetate esters, and terpenoids at higher fermentation temperatures correlated with a more pronounced tropical character, particularly with the ale yeasts. These results highlight the intricate relationships between thiol levels and concurrent volatile compounds, emphasizing that elevated thiol presence alone does not directly translate to heightened tropical aromatic expression in beer.

Saccharomyces cerevisiae is a model organism with key industrial relevance in wine fermentation and other biotechnological processes. Identifying single-nucleotide polymorphisms (SNPs) linked to quantitative traits is essential for understanding the genetic basis of strain performance. Most previous studies have frequently focused on lineage-based comparisons, limiting the resolution of genotype–phenotype associations. To deal with this constraint, we applied regression and machine-learning models to characterise SNPs and genes associated with continuous oenological traits in wine strains. Four phenotypes were evaluated: proliferation efficiency, proliferation rate, lag phase, and area under the growth curve. Genome-wide SNP data were encoded and used to train predictive models based on Ridge regression, Support Vector Machines, K-nearest Neighbours, and Random Forest. Model performance was evaluated through cross-validation, and key SNPs were prioritised using feature-importance metrics. Functional enrichment of the associated genes was performed using curated biological databases to provide a mechanistic context. This integrative approach identified genomic regions consistently linked to fermentation traits and revealed candidate genes involved in stress adaptation and metabolic regulation. The results refine genotype–phenotype associations in wine yeasts and establish a reproducible framework for future experimental validation of functionally relevant variants.

When heat treating (pasteurizing) bottled or canned, carbonated beverages, such as beer and beer products or soft drinks, to reduce and/or kill any potential product spoilage organisms in their respective container, usually large tunnel pasteurizers are used. These machines spray hot water over the containers to ultimately reach a sufficient core temperature in the beverage container. Studies have shown that this process water contains a high count of diverse microorganisms. Reports from the industry and proven incidents imply that in very rare cases this process water and the related ingress of microorganisms can be detected in microbiological quality control of the product. To this date no investigations have proven or disproven these rare events. This study aims to collect evidence on the likelihood of these events occurring during large scale pasteurization. The possibility of an exchange with the environment during pasteurization could be proven by loss of CO2 throughout the process. This only occurred in bottles closed with crown corks, not in swing tops and cans. An ingress of process water could not be proven in the presented study but evidence was found that crown cork bottles are also the most likely container type for such a phenomenon to happen.