Predicting and improving complex beer flavor through machine learning.

The perception and appreciation of food flavor depends on many interacting chemical compounds and external factors, and therefore proves challenging to understand and predict. Here, we combine extensive chemical and sensory analyses of 250 different beers to train machine learning models that allow predicting flavor and consumer appreciation. For each beer, we measure over 200 chemical properties, perform quantitative descriptive sensory analysis with a trained tasting panel and map data from over 180,000 consumer reviews to train 10 different machine learning models. The best-performing algorithm, Gradient Boosting, yields models that significantly outperform predictions based on conventional statistics and accurately predict complex food features and consumer appreciation from chemical profiles. Model dissection allows identifying specific and unexpected compounds as drivers of beer flavor and appreciation. Adding these compounds results in variants of commercial alcoholic and non-alcoholic beers with improved consumer appreciation. Together, our study reveals how big data and machine learning uncover complex links between food chemistry, flavor and consumer perception, and lays the foundation to develop novel, tailored foods with superior flavors.

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.

Quantification of Hop-Derived Bitter Compounds in Beer Using Liquid Chromatography Mass Spectrometry.

Hops (Humulus lupulus L.) are essential raw materials for beer brewing, and the major contributors to beer bitterness are isohumulones (iso-α-acids) and humulinones. In recent years, many breweries have focused on the production of hop-forward beer styles by adding hops after or during the cold fermentation stage, which will tend to release humulinones or other hop-derived bitter compounds. In this study, a LC-MS/MS method was developed for quantification of 60 hop-derived bitter compounds in 25 min. Reverse-phase chromatography with an alkaline methanol/acetonitrile (70:30) mobile phase was used for the separation. The quantitative range was 0.053-3912 ng/mL with correlation coefficient r > 0.99, and the LOQ were 0.26 and 0.053 ng/mL for iso-α-acids and humulinones. Precision (RSD < 5.0%) and accuracy (recovery 86.3%-118.1%) were both satisfactory. The abundance of hop-derived bitter compounds in the dry-hopped beer (Double-India Pale Ale) and the nondry-hopped beer (Vienna Lager) were monitored throughout the fermentation and storage stages, and the formation of oxidation and cyclization products showed difference profiles between these two beers. The quantification results reveal how hop-derived bitter compounds change throughout the brewing process, as well as the influence of hops and brewing techniques on beer bitterness.

Effect of Coriander Seed Addition at Different Stages of Brewing on Selected Parameters of Low-Alcohol Wheat Beers.

In recent years, there has been a significant decline in interest in high-alcohol beers, while interest in low- and non-alcohol beers is growing. The aim of this study was to investigate the influence of the addition of coriander seeds at various stages of the production of low-alcohol wheat beer (mashing, boiling, and fermentation). The presented article uses biological methods to produce low-alcohol beer. For this purpose, first, the mashing process was modified (breaking 44 °C for 20 min, followed by 75 °C for 60 min). The chemical composition and aroma components of the obtained beers were determined using various chromatographic methods (HPLC, GC-MS, and GC-O). Differences were found between the aroma components depending on the stage of production at which the coriander seeds were added. Beers with the addition of coriander seeds at the fermentation stage had the highest terpene content (linalool, camphor, trans-linalool oxide, and γ-terpinene) and boiling (myrcene, limonene, citronellol, and geraniol). The least desirable process is the addition of coriander seeds at the mashing stage due to the lowest content of volatile compounds. Additionally, beers with the addition of coriander seeds for fermentation were characterized by a higher content of antioxidant compounds. This proves that the addition of coriander seeds during beer production could improve the fermentation process and modify the quality of the obtaining beer.

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.

Biodiversity and brewing attitude of non-Saccharomyces strains isolated from Uruguayan vineyards and other ecosystems.

In recent years, interest in non-Saccharomyces yeasts for the innovation and development of different and alternative beer styles has been increasing, especially for the microbrewing industry. This work studied the biodiversity of non-Saccharomyces yeasts based on isolates from grapes of different Uruguayan vineyards, craft breweries and raw materials, with the aim of selecting autochthonous non-Saccharomyces yeasts with a brewing attitude. Brewing tests were performed on synthetic wort developed for this purpose, and the evolution of alcoholic fermentation was monitored by measuring glucose, maltose, maltotriose consumption, ethanol and glycerol production and final sensory analysis. A total of two hundred seventy-one yeast strains belonging to different genera were evaluated according to these parameters. After evaluating alcoholic fermentation performance, a native yeast strain belonging to the species Starmerella meliponinorum was selected due to its high maltotriose consumption and glycerol production, making it a very promising brewing yeast, especially for production of low carbohydrate beers.

An integrative multi-omics approach aimed to gain insight on the effect of composition, style, yeast, and wheat species on wheat craft beer flavour.

This study was aimed to unravel the effect of raw materials (barley and wheat), wheat concentration (0, 25, 40, and 100 %), wheat species (common and durum), beer style (Blanche and Weiss), and yeast (US-05 and WB-06) on the chemical composition, volatiles, and sensory profile of wheat craft beers by using a multivariate statistical approach. Beer samples were analysed for their composition, volatiles and sensory profile and data were processed using unsupervised multivariate analyses, PLS regression and a multi-omics approach using multi-block PLS-DA. Multi-block variable sparsification was used as an embedded dimension reduction step. The adopted multi-omics approach permitted to correctly classify beers with different styles and wheat concentration, and to accurate classify (95 % accuracy) beers according to yeast type. Wheat species was of lower importance since it permitted a classification with 49 % accuracy which increased to 74 % in Blanche beers, thus suggesting that malting flattened differences determined by wheat species.

Production of the prolyl endoprotease (PEP) from Aspergillus sp. FSDE 16 by solid-state fermentation (SSF) and use for producing a gluten-free beer.

Beer is a beverage that contains gluten and cannot be consumed by people with celiac disease. In this context, the enzyme prolyl endoprotease (PEP) can be used to reduce the gluten content in beer. The present study aimed to produce the PEP from Aspergillus sp. FSDE 16 using solid-state fermentation with 5 conditions and comparing with a similar commercial enzyme produced from Aspergillus niger in the production of a gluten-free beer. The results of the performed cultures showed that during the culture, the most increased protease activity (54.46 U/mL) occurred on the 4th day. In contrast, for PEP, the highest activity (0.0356 U/mL) was obtained on the 3rd day of culture in condition. Regarding beer production, cell growth, pH, and total soluble solids showed similar behavior over the 7 days for beers produced without enzyme addition or with the addition of commercial enzyme and with the addition of the enzyme extract produced. The addition of the enzyme and the enzyme extract did not promote changes, and all the beers produced showed similar and satisfactory results, with acid pH between 4 and 5, total soluble solids ranging from 4.80 to 5.05, alcohol content ranging from 2.83% to 3.08%, and all beers having a dark character with deep amber and light copper color. Gluten removal was effectively using the commercial enzyme and the enzyme produced according to condition (v) reaching gluten concentrations equal to 17 ± 5.31 and 21.19 ± 11.28 ppm, respectively. In this way, the production of the enzyme by SSF and its application in the removal of gluten in beer was efficient.

A State-of-the-Science Review of Alcoholic Beverages and Polycyclic Aromatic Hydrocarbons.

BACKGROUND: The association between alcohol and certain cancers is well established, yet beyond ethanol and its metabolite acetaldehyde, little is known about the presence of other carcinogenic compounds in alcoholic beverages, including polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (a Group I carcinogen). OBJECTIVES: We summarized the published literature on PAH levels in alcoholic beverages to identify potential gaps in knowledge to inform future research. METHODS: Medline and Scopus were searched for primary research published from January 1966 to November 2023 that quantified PAH levels among various types of alcoholic beverages, including whisky, rum, brandy, gin, vodka, wine, and beer. Studies that were not primary literature were excluded; only studies that quantified PAH content in the specified alcoholic beverages were included. RESULTS: Ten studies published from 1966 to 2019 met the criteria for review. Other than beverage type, no publication reported selection criteria for their samples of tested alcohol products. Studies used a variety of analytical methods to detect PAHs. Of the 10 studies, 7 were published after 2000, and 6 assessed <20 products. Of the studies, 7 examined spirits; 3, beer; and 4, wines. Benzo[a]pyrene was most prevalent among spirit products, particularly whisky, with values generally exceeding acceptable levels for drinking water. Some beer and wine products also contained PAHs, albeit at lower levels and less frequently than spirit products. DISCUSSION: PAHs are found in some alcohol products and appear to vary by beverage type. However, there is an incomplete understanding of their presence and levels among large, representative samples from the range of currently available alcohol products. Addressing this gap could improve understanding of alcohol-cancer relationships and may have important implications for public health and the regulation of alcohol products. In addition, novel methods, such as direct mass spectroscopy, may facilitate more thorough testing of samples to further investigate this relationship. https://doi.org/10.1289/EHP13506.

Fate of pesticide residues in beer and its by-products.

Sustainable beer production requires a comprehensive assessment of potential hazards such as pesticides in both the finished product and waste streams, as these streams can be used to create high-value by-products. This study presents the tracking of 13 fungicides (azoxystrobin, boscalid, epoxiconazole, fenpropidin, fenpropimorph, fluquiconazole, flutriafol, fluxapyroxad, kresoxym-methyl, spiroxamine, propiconazole, prothioconazole-desthio, and tebuconazole), two insecticides (chlorpyrifos-methyl and deltamethrin), one herbicide (glyphosate), and one growth regulator (mepiquat) through the beer brewing process. Field-treated rye, wheat, and barley samples containing pesticide residues were used as adjunct during brewing. Samples of the beer as well as the by-products (spent grain, spent hops, trub and spent yeast) were collected and extracted with a modified QuEChERS method for pesticide residues analysis using GC-MS/MS and LC-MS/MS. Results show that an average of 58% of pesticide residues are retrieved in the by-products with the highest fraction (53%) recovered in the spent grain, 4% in trub, 1% in spent hops, no residues detected in spent yeast and 9% in the beer. This is consistent with these nonpolar pesticides tending to remain adsorbed to the spent grain during brewing. Glyphosate and mepiquat, the most polar pesticides included in this study, showed a different behavior, with the largest fraction (>80%) being retrieved in sweet wort and transferred to the beer. Processing factors were generated for each pesticide from the adjunct to the beer and to the four by-products.

The effect of mixed culture fermentation of Saccharomyces cerevisiae and Saccharomyces cerevisiae var. diastaticus on fermentation parameters and flavor profile.

Belgian Saisons and Lambics are two well-known examples in the brewing industry of mixed fermentations, combination of two or more yeast and/or bacteria strains. The purpose of this study was to determine the impact different pitch rates of Saccharomyces cerevisiae (traditional brewing yeast) and S. cerevisiae var. diastaticus (a variant associated with Belgian styles) had on the fermentation kinetics and concentration of the volatile compounds in the finished beers. A series of brews were performed utilizing ratios of S. cerevisiae and diastaticus. The fermentations were heavily monitored, and a model was used to fit fermentation variables. It was found that mixed fermentations produced behaviors that were predictable and proportional to the mixture ratios. As expected, the pure cultural fermentations of diastaticus had a slower fermentation midpoint (M) at 45.45 h versus 28.28 h for S. cerevisiae with the mixed ones falling in between the two. Flavor and aroma play a key role in the acceptability of beer. The mixed fermentations showed a combination of the two different yeast strains aromatic profiles. When combined, there was a strong linearity between alcohols (R2  = 0.94), esters (R2  = 0.89), and the overall total (R2  = 0.91) volatile compounds. PRACTICAL APPLICATION: Modeling is a widely utilized tool in several different fields. The purpose of this research is to apply modeling techniques to describe the fermentation speed and flavor profile of a mixed fermentation between S. cerevisiae and diastaticus. The equations from this data can be used by brewers for product development purposes to make beers with certain flavor profiles within a desired timeframe.

Exploring the potential of probiotic-enriched beer: Microorganisms, fermentation strategies, sensory attributes, and health implications.

Probiotic-enriched beers have emerged as an innovative solution for delivering beneficial microorganisms, particularly appealing to consumers seeking non-dairy options. However, navigating the complex beer environment presents challenges in effectively cultivating specific probiotic strains. This review aims to promote innovation and distinctiveness within the brewing industry by providing insights into current research on the integration of probiotic microorganisms into beer production, thereby creating a functional beverage. The review explores the effects of probiotic incorporation on the functional, technological, and sensory attributes of beer, distinguishing contributions from bacterial and yeast, as well as potential health benefits. Probiotic microorganisms encounter hurdles during beer production, including ethanol, hops, CO2 levels, pH, oxygen, and nutrients. Ethanol tolerance mechanisms vary among bacteria and yeasts, with specific lactic acid bacteria showing resistance to hop compounds. Hops, crucial for beer categorization, exert a timing-dependent impact on probiotics-early isomerization impedes growth, while late additions yield non-isomerized antibacterial properties. Effective probiotic integration necessitates precise post-fermentation addition stages to ensure viability and flavor. The sensory impact and consumer reception of probiotic-enriched beers require further exploration. Probiotics must endure storage conditions to qualify as functional beer, while limited research investigates health advantages, urging enhanced production techniques, sensory optimization, and clinical validation.

Systematic profiling of ale yeast protein dynamics across fermentation and repitching.

Studying the genetic and molecular characteristics of brewing yeast strains is crucial for understanding their domestication history and adaptations accumulated over time in fermentation environments, and for guiding optimizations to the brewing process itself. Saccharomyces cerevisiae (brewing yeast) is among the most profiled organisms on the planet, yet the temporal molecular changes that underlie industrial fermentation and beer brewing remain understudied. Here, we characterized the genomic makeup of a Saccharomyces cerevisiae ale yeast widely used in the production of Hefeweizen beers, and applied shotgun mass spectrometry to systematically measure the proteomic changes throughout 2 fermentation cycles which were separated by 14 rounds of serial repitching. The resulting brewing yeast proteomics resource includes 64,740 protein abundance measurements. We found that this strain possesses typical genetic characteristics of Saccharomyces cerevisiae ale strains and displayed progressive shifts in molecular processes during fermentation based on protein abundance changes. We observed protein abundance differences between early fermentation batches compared to those separated by 14 rounds of serial repitching. The observed abundance differences occurred mainly in proteins involved in the metabolism of ergosterol and isobutyraldehyde. Our systematic profiling serves as a starting point for deeper characterization of how the yeast proteome changes during commercial fermentations and additionally serves as a resource to guide fermentation protocols, strain handling, and engineering practices in commercial brewing and fermentation environments. Finally, we created a web interface (https://brewing-yeast-proteomics.ccbb.utexas.edu/) to serve as a valuable resource for yeast geneticists, brewers, and biochemists to provide insights into the global trends underlying commercial beer production.

Characteristics analysis of solid waste generation and carbon emission of beer production in China.

As the largest beer producer and consumer in the world, China's endeavors to reduce solid waste generation (SWG) and carbon emissions (CEs) in the course of beer production assume paramount significance. This study aims to assess the SWG and CEs in beer production within China at both national and provincial levels, and further delves into the spatial distribution characteristics and evolving patterns across the country. Key findings of the study include:(1) Peak SWG and CEs were recorded in 2013, reaching 861.62 million tons and 2315.10 tCO2e, respectively, followed by a consistent decline. (2) Among the three types of solid waste, spent grain exhibited the highest generation rate, contributing to 94.38% of the total. (3) The emergence of China's beer industry dates back to the 1980s in the northeastern region, expanding to the southeastern and the Yangtze River Basin during the 1990s, ultimately extending nationwide. (4) The spatial distribution of beer production revealed significant regional disparities and notable industry concentration. Notably, many provinces witnessed reduced CEs from beer production starting in 2015, although the extent of reduction varied in different provinces. These findings serve as a scientific foundation for formulating emission reduction strategies in beer producing and offer insights for other food industries in China.

Interesting Behavior of Geranic Acid during the Beer Brewing Process: Why Could Geranic Acid Remain at a Higher Level Only in the Beer Using Sorachi Ace Hops?

Hops are among the most important ingredients in beer that contribute to beer flavor. Consequently, novel types of hops have been bred and widely used worldwide. For example, the Sorachi Ace hop imparts characteristic varietal aromas, including woody, pine-like, citrus, dill-like, and lemongrass-like aromas, to the finished beer. In our previous study, the unique volatile compound geranic acid was significantly detected only in the test beer brewed with the Sorachi Ace hop; moreover, the coexistence of geranic acid and other hop-derived flavor compounds could result in the characteristic aroma of the Sorachi Ace beers. In this study, selected hop-derived flavor compounds, including geranic acid, were compared among 17 hop varieties. The geranic acid content in the Sorachi Ace hop was the highest among the studied hops. We also investigated the behavior of geranic acid and related flavor compounds throughout the fermentation process. The content of geranic acid was higher than those of the other compounds during fermentation. Next, we compared the concentrations of these compounds in kettle-, late-, and dry-hopped beers using Sorachi Ace hop. The results revealed that geranic acid remained at higher concentrations from the worts to finished beers despite the decrease in the content of other hop-derived flavor compounds as a result of evaporation and/or other factors during brewing. Further, geranic acid could remain at high levels in the test-brewed beers with Sorachi Ace hops because of its behavior as an acid throughout the brewing process, including during wort boiling and fermentation.

Development of gluten-free craft beer: Impact of brewing process on quality attributes and consumer expectations for sensory properties.

To date, few studies investigated the differences between the two main gluten-free (GF) brewing techniques, such as the use of enzymes and the use of unconventional GF grains in brewing, by consumer perspective. In this study a GF beer brewed with sorghum and quinoa, as brewing adjuncts, was compared to the enzymatic-treated counterpart, in order to evaluate the effect of deglutinization treatment on physicochemical, volatile, and sensory characteristics of final beer. Moreover, the influence of brewing process and raw materials information on consumers' sensory perceptions, willingness to buy (WTB) and willingness to pay (WTP) was also investigated (n = 105 consumers), under blind (B), expected (E), and informed (I) conditions. The enzymatic-treated sample showed comparable physicochemical attributes with the untreated counterpart, except for a significant reduction in color and foam stability (p < 0.05). Non-significant difference between samples was found in the overall liking, WTB, and WTP mean scores in all three sensory test conditions (p > 0.05). The information about the deglutinization treatment had a negative impact on overall liking (p < 0.01), although WTP for both samples was significantly higher in the informed test than in blind condition (p < 0.05). Overall, Check-All-That-Apply test results confirmed that the deglutinization treatment does not affect the beer sensory profile, even if the information about brewing ingredients and technologies may slightly influence the consumers' sensory perception. Therefore, this result proves that it is possible to produce a marketable GF beer, simply by partially replacing 40% of barley malt with unconventional GF grains, without using enzymes for gluten reduction purpose.

Revealing Potential Genes Affecting Flocculation and/or Viability of Saccharomyces pastorianus by Comparative Genomic Analysis.

Yeast flocculation and viability are critical factors in beer production. Adequate flocculation of yeast at the end of fermentation helps to reduce off-flavors and cell separation, while high viability is beneficial for yeast reuse. In this study, we used comparative genomics to analyze the genome information on Saccharomyces pastorianus W01, and its spontaneous mutant W02 with appropriate weakened flocculation ability (better off-flavor reduction performance) and unwanted decreased viability, to investigate the effect of different gene expressions on yeast flocculation or/and viability. Our results indicate that knockout of CNE1, CIN5, SIN3, HP-3, YPR170W-B, and SCEPF1_0274000100 and overexpression of CNE1 and ALD2 significantly decreased the flocculation ability of W01, while knockout of EPL1 increased the flocculation ability of W01. Meanwhile, knockout of CIN5, YPR170W-B, OST5, SFT1, SCEPF1_0274000100, and EPL1 and overexpression of SWC3, ALD2, and HP-2 decreased the viability of W01. CIN5, EPL1, SCEPF1_0274000100, ALD2, and YPR170W-B have all been shown to affect yeast flocculation ability and viability.

Proteomics and Metabolomics Reveal that an Abundant α-Glucosidase Drives Sorghum Fermentability for Beer Brewing.

Sorghum (Sorghum bicolor), a grass native to Africa, is a popular alternative to barley for brewing beer. The importance of sorghum to beer brewing is increasing because it is a naturally gluten-free cereal, and climate change is expected to cause a reduction in the production of barley over the coming decades. However, there are challenges associated with the use of sorghum instead of barley in beer brewing. Here, we used proteomics and metabolomics to gain insights into the sorghum brewing process to advise processes for efficient beer production from sorghum. We found that during malting, sorghum synthesizes the amylases and proteases necessary for brewing. Proteomics revealed that mashing with sorghum malt required higher temperatures than barley malt for efficient protein solubilization. Both α- and ß-amylase were considerably less abundant in sorghum wort than in barley wort, correlating with lower maltose concentrations in sorghum wort. However, metabolomics revealed higher glucose concentrations in sorghum wort than in barley wort, consistent with the presence of an abundant α-glucosidase detected by proteomics in sorghum malt. Our results indicate that sorghum can be a viable grain for industrial fermented beverage production, but that its use requires careful process optimization for efficient production of fermentable wort and high-quality beer.

Aroma Profile Development in Beer Fermented with Azacca, Idaho-7, and Sultana Hops.

Hops are among the most costly and environmentally impactful raw materials used in brewing, yet they play a crucial role in the aroma of beer. However, predicting beer aroma based on hop variety or hopping method remains arduous. This is partly because hop oils are unique for each hop variety, and they may be biotransformed by yeast enzymes during fermentation. Even slight molecular structure modifications can dramatically affect the organoleptic properties of beer. Through combined chemical and sensory analysis of dry-hopped beers prepared with different hop varieties (Azacca, Idaho-7, and Sultana), this work aimed to profile the aromas and the overall biotransformation processes taking place during fermentation. A total of 51 volatile organic compounds (VOCs) were semi-quantified and monitored: 19 esters, 13 sesquiterpenes, 7 ketones, 7 alcohols, 4 monoterpenes, and 1 volatile acid. There were significant similarities in the measured analytes and perceived aromas of these beers, but one hop variety (Sultana) delivered an increased quantity of unique aromas and an increased concentration of volatiles in the headspace for the same quantity of hop pellets added. This work provides practical information to brewers who utilize hops in beer production.