Assessment of the impact of unmalted cereals, hops, and yeast strains on volatolomic and olfactory profiles of Blanche craft beers: A chemometric approach

This study investigated the impact of changes in craft beer formulation, by modifying the unmalted cereal [(durum (Da) and soft (Ri) wheat), emmer (Em)], hops [Cascade (Ca) and Columbus (Co)], and yeast strains [M21 (Wi) - M02 (Ci)], on volatolomic, acidic, and olfactory profiles. Olfactory attributes were evaluated by the trained panel. Volatolomic and acidic profiles were determined by GC-MS. The sensory analysis detected significant differences for 5 attributes, including olfactory intensity and finesse, malty, herbaceous, and floral notes. Multivariate analysis of volatiles data, showed significant differences among the samples (p < 0.05). DaCaWi, DaCoWi, and RiCoCi beers differ from the others by their higher concentrations of esters, alcohols, and terpenes. A PLSC analysis was carried out between volatiles and odour attributes. As far as we know, this is the first investigation that shed light on the impact of 3-factors interaction on the sensory-volatolomic profile of craft beers, through a comprehensive multivariate approach.

Single and Interactive Effects of Unmalted Cereals, Hops, and Yeasts on Quality of White-Inspired Craft Beers

White beers owe their name to their straw yellow colour deriving from the use of unmalted wheat, which also supplies a relatively high protein content causing haze formation. This study aimed to develop white-inspired craft beers made with combinations of three mixtures of barley malt/unmalted wheat (alternatively durum-var. Dauno III, soft-var. Risciola, or emmer-var. Padre Pio), two hop varieties (Cascade or Columbus), and two Saccharomyces cerevisiae strains (Belgian yeast and a high-ester producing yeast); and assess the single and interactive effects of these ingredients on physical, chemical, and sensory characteristics of the beers. According to the graphical representation of the results for the Principal Component Analysis, most of the samples appear overlapped since they had similar characteristics, but it was possible to highlight two clusters of beers different from the others: those produced with (a) Risciola wheat and Columbus hop and (b) Dauno III wheat, Cascade hop, and the Belgian yeast. The beers of these clusters obtained the highest scores for their overall quality that, in turn, was positively correlated with concentrations of citric acid, 4-hydroxybenzoic acid, syringic acid, and epicatechin; alcohol %, colour, amount and persistence of foam, intensity of fruity flavour, and body.

A unifying approach to wheat beer flavour by chemometric analyses. Could we speak of 'terroir'?

Raw materials are recognized to affect the sensory profile of 'Blanche' craft beers and their 'terroir'. Two common wheat (Triticum aestivum, L.) were harvested in three experimental fields with different pedo-climatic conditions and altitudes, and then used for beer production. The taste and flavour of wheat beers were analysed by sensory (panel and consumer test) and SPME GC-MS analyses. Panel dataset was processed by multivariate statistical analyses: a principal component analysis (PCA) revealed that formulation was the main source of variation of sensory profile in wheat beers and a generalized Procrustes analysis (GPA) showed how wheat origin affected the sensory profiles of wheat craft beers based on the consensus among panelists. Moreover, a partial least-squares discriminant analysis (PLS-DA) on VOCs permitted to discriminate and characterize beers selected by a panel-driven approach. By comparing panel and VOCs results, it was possible to highlight that higher altitudes of wheat cultivation determine an increase of pleasant notes such as fruity and herbal. A PCA on consumer test data confirmed that formulation was the main factor affecting liking scores and that the preferences were affected by age, involvement and frequency of use. An internal preference map combining panel and consumer data suggested that the majority of preferences are driven by a few key sensory attributes. Differences in liking among the considered beers revealed two main consumer groups.

Effects on beer colloidal stability of full-scale brewing with adjuncts, enzymes, and finings

This study investigated the effects on beer colloidal stability of full-scale brewing with adjuncts, enzymes, and finings. Industrial lager beers were produced solely from barley malt or from barley malt with adjuncts (corn grist and starch syrup or unmalted barley). Various stabilization aids were also used (silica gel, PVPP, proline-specific endoprotease, carrageenan). Predictive shelf-life tests were conducted. We analyzed the content of compounds (proteins and polyphenols) generally related to beer colloidal stability. The results show that the haze-forming potential of the beer during storage can be evaluated based on the coagulable nitrogen content (high molecular weight proteins), rather than the total nitrogen content and polyphenol content. A very strong and statistically significant negative correlation was observed between the concentration of coagulable nitrogen and beer colloidal stability. When brewing was conducted with 49% barley raw material and exogenous proteases, especially proline-specific endoprotease, the coagulable nitrogen content fell and beer colloidal stability improved. The use of corn grist and starch syrup as up to 40% of the total grist resulted in a 30% longer physical shelf life compared to the all-malt beer.

The Effect of the Addition of Ozonated and Non-Ozonated Fruits of the Saskatoon Berry (Amelanchier alnifolia Nutt.) on the Quality and Pro-Healthy Profile of Craft Wheat Beers

Research into the suitability of domestic raw materials, including, for example, new wheat cultivars and fruit additives for the production of flavoured beers, is increasingly being undertaken by minibreweries and craft breweries. The fruits of the Saskatoon berry are an important source of bioactive compounds, mainly polyphenols, but also macro- and microelements. The fruits of two Canadian cultivars of this species, 'Honeywood' and 'Thiessen', were used in this study. Physicochemical analysis showed that wheat beers with the addition of non-ozonated fruit were characterised by a higher ethanol content by 7.73% on average. On the other hand, enrichment of the beer product with fruit pulp obtained from the cv. 'Thiessen' had a positive effect on the degree of real attenuation and the polyphenol profile. Sensory evaluation of the beer product showed that wheat beers with the addition of 'Honeywood' fruit were characterised by the most balanced taste and aroma. On the basis of the conducted research, it can be concluded that fruits of both cvs. 'Honeywood' and 'Thiessen' can be used in the production of wheat beers, but the fermentation process has to be modified in order to obtain a higher yield of the fruit beer product.

Feasibility of Defatted Juice from Sea-Buckthorn Berries (Hippophae rhamnoides L.) as a Wheat Beer Enhancer

Juice made from sea-buckthorn berries (Hippophae rhamnoides L.) is a valuable source of bioactive compounds, vitamins, as well as micro- and macronutrients. By applying defatted sea-buckthorn juice, it is possible to enhance wheat beer and change its sensory properties and the contents of bioactive compounds in the finished product. A sensory assessment showed that wheat beers with a 5% v/v addition of sea-buckthorn juice were characterised by a balanced taste and aroma (overall impression). Physicochemical analyses showed that, compared to the control samples, wheat beers enhanced with defatted sea-buckthorn juice at a rate of 5% v/v or 10% v/v had high total acidity with respective mean values of 5.30 and 6.88 (0.1 M NaOH/100 mL), energy values lower on average by 4.04% and 8.35%, respective polyphenol contents of 274.1 mg GAE/L and 249.7 mg GAE/L, as well as higher antioxidant activity (measured using DPPH, FRAP, and ABTS assays). The findings show that the samples of wheat beer enhanced with sea-buckthorn juice had average ascorbic acid contents of 2.5 and 4.5 mg/100 mL (in samples with 5% v/v and 10% v/v additions, respectively) and contained flavone glycosides, e.g., kaempferol-3-O-glucuronide-7-O-hexoside. Based on the current findings, it can be concluded that wheat beer enhanced with sea-buckthorn juice could emerge as a new trend in the brewing industry.

Suitability of Selected Winter Cultivars of Wheat from Production of Wheat Beer

The study investigated the feasibility of three winter cultivars of wheat – Elixer, Rockefeller and Gimantis, for production of wheat beer. Reference samples were produced from commercially available wheat malt. The findings showed the beer produced from commercially available wheat malt presented the best sensory and physicochemical parameters, including real final fermentation of 70.11%. The results related to the investigated wheat cultivars showed good quality properties in the beer produced from malts obtained from Gimantis cultivar (content of CO2 – 0.58%), and from Rockefeller cultivar (alcohol content - 4.62% v/v). A similar relationship was observed in the sensory assessment. The findings related to beer produced from malt of Elixer wheat cultivar showed relatively low effectiveness of the production process (69.7%) and final beer fermentation (65.52%), and at the same time high contents of polyphenols (210 mg/dm3) and antioxidant activity. Wheat malts produced from Gimantis and Rockefeller cultivars can effectively be used as a raw material in beer production; on the other hand, malt from Elixer cultivar, found with higher antioxidant contents, may be used as an additive to be applied in a small quantity in the mashing process in order to enhance the beer in terms of its potential health benefits.

Quality and Pro-Healthy Properties of Belgian Witbier-Style Beers Relative to the Cultivar of Winter Wheat and Raw Materials Used

Unmalted wheat grain and barley malt are the basic materials used in the production of Belgian wheat beers known as Witbier. A change in the ingredients defined in the recipe, by which part of the unmalted wheat is replaced with wheat malt, can positively affect the quality of the beverage produced. The purpose of the study was to brew Witbier-style beers made from four cultivars of winter wheat, with a 50% share of unmalted wheat and barley malt as well as Witbier-style beers made from four wheat cultivars, where 25% of unmalted wheat was replaced with wheat malt. Physicochemical and sensory analyzes showed mild differences in the quality of the beer products, more specifically higher alcohol content (by 11.33%) were found in beers made without the addition of wheat malt, while higher sensory attractiveness and 17.13% higher total polyphenol content were identified in beers enhanced with wheat malt. Phenolic compounds were identified using UPLC-PDA-MS/MS. The highest flavanol content, including kaempferol 3-O-rhamnoside-7-O-pentoside, was found in beers produced using wheat grains of the ‘Elixer’ cultivar, whether or not wheat malt was added; the values were 1.31 mg/L in E50 beer, and 1.39 mg/L in E25 beer. The same beer samples with the highest antioxidant and antiradical activity were found (in E25 beer, 2.35 mmol TE/L, and in E50 beer, 2.12 mmol Fe^2+/L). The present findings show that the investigated wheat cultivars may be used in beer production, whereas replacing part of unmalted wheat with wheat malt can improve the sensory profile of the beer produced.

Effect of malting process duration on malting losses and quality of wheat malts

The study assesses impact of malting process duration on malting losses and quality of malts obtained from three varieties of winter wheat, i.e., Elixer, Rockefeller and Gimantis. The findings show that increased duration of the malting process (from 4 to 7 days) corresponded to greater total weight loss, with the most significant differences observed between 5-day and 6-day wheat malts. The qualitative analysis of the malts was carried out in accordance with EBC methodology. The assessments showed that the 5-day long malting process applied to the relevant wheat varieties resulted in production of high-quality malt with optimum malting losses observed in the case of Elixer and Rockefeller varieties. Slightly higher malting losses were identified in the case of Gimantis, and the malt obtained from this variety had very high contents of soluble protein (on average 5.34% d.m.) and Kolbach Index (average of 50.49%), which reflects high proteolytic activity during the grain malting process and a need to modify the malting process for this variety.

Quality Characteristics of Wheat Malts with Different Country of Origin and Their Effect on Beer Brewing

The characteristics of wheat malt, wort, and beer from two Korean wheat varieties (Keumkang and Anzunbaengi; KM and AM, respectively) were compared to those of two commercial wheat malt controls from the USA and Germany (UM and GM), to examine the feasibility of Korean wheat for brewing. The quality parameters of four wheat malts, chemical properties of wort using them, volatile compounds, sensory attributes, and consumer acceptability of four final beers (KB, AB, UB, and GB) were analysed. Additionally, the relationship of each parameter was determined through multiple factor analysis. Korean wheat malts were different from control malts in free amino nitrogen (FAN), soluble and total nitrogen, and Kolbach index. The extract (81.8–83.2%) and diastatic power (407–477 WK°) of all samples were in the brewing field’s recommended range. The FAN and yeast cell population of the wort samples were similar during fermentation except on the initial day, which showed a high FAN and yeast cell population for KM wort. Eleven volatile compounds with variable importance in projection scores above 1.0 were responsible for discrimination of the beer samples by partial least squares discriminant analysis. The four beer samples’ overall acceptance scores were not significantly different. However, their acceptance trends were different depending on consumer preference segments by agglomerative hierarchical clustering analysis, implying the need for product development depending on the target consumer. Regarding sensory attributes, KB had a less fruity flavour than the other beer samples ( $p<0.05$ ) and sweetness of AB tended to be higher than the others. An association plot based on multiple factor analysis of the wheat beer samples, volatile compounds, sensory properties, and overall acceptance showed that sweetness, alcohol aroma, and fruity flavour were closely associated with AB and overall acceptance, while 2,3-butanediol and turbidity were placed opposite side of there.

Research of Malting Procedures for Winter Hard Wheat Varieties-Part I

This paper examines the influence of the malting process of red hard wheat varieties (which have many characteristics of soft wheat varieties and represent a transitional form between durum and soft wheat). According to the values of total and soluble proteins and viscosity of wort these wheat varieties belong to the second malting quality group. To establish the individual response of each variety and estimate how the chosen varieties respond in groups to different process conditions, sixteen varieties were selected and malted according to the standard procedure (A), restrictive procedure (B), and intense procedure (C). Starting wheat, indicators of micromalting process success, and finished malts were analyzed. It was found that the restrictive procedure (B) gives poor results for the values of proteolysis performance parameters (soluble N, free amino nitrogen (FAN)) with simultaneous disturbance and values of cytolytic degradation (viscosity and filtration time) and extract yield. At the same time, this procedure lacks a stronger individual response of an individual variety to the process conditions during malting (F/C difference and extract yield). The optimal malting process for the specified assortment would include the modification of processes B and C in a way to alleviate the restrictive conditions in process B, or in a way to reduce the intensity of the decomposition in process C.

Research on the Malting Properties of Domestic Wheat Varities

This study aimed to establish the suitability of new Croatian wheat varieties for the production of pale wheat malt. Four new varieties/breeding lines from the Agricultural Institute Osijek were tested (Indira, OSK. 378/19, OSK. 346/20, and OSK. 353/20). The quality of starting wheat, the success of the micromalting process and the quality of finished malts were analyzed. The obtained results showed that the tested varieties/breeding lines meet the quality criteria for pale beer malt, and can be classified in the II malting quality group. The vast majority of quality indicators examined in this research showed values within the limits recommended for pale wheat malt. The obtained results were very good considering that these varieties are not intended for malting, nor in their selection process attention was paid to meet the brewing quality criteria. Due to the sensory characteristics of beer, the possibility of intervention during the malting process is limited, therefore when selecting wheat for malting, attention should be paid to the lowest possible content of total and soluble proteins, which can be achieved by appropriate agrotechnical measures in cultivation.

Progress of the use of alternatives to malt in the production of gluten-free beer

Beer is the most widely consumed alcoholic drink in the world, but it is not suitable for patients who suffer from celiac disease (CD) because its main ingresdients, barley or wheat, contain gluten. Approximately 1% of the world's population is affected by CD, and the development of gluten-free beer is imperative. Gluten-free beers produced using alternative materials, such as rice, sorghum, maize, millet, oats, and pseudocereals (e.g., buckwheat, quinoa and Amaranth), are studied in this review that examines the effects of specific substitutions on the different characteristics of the final beer to ensure the appropriateness of their use. The use of alternatives to malt may affect the quality of gluten-free beer and result in some negative consequences. Accordingly, the influential factors are discussed in terms of the total substitution of malt with other grains in the production of beer. Research results have provided some new alternative solutions for the production of gluten-free beer, such as the use of malted grains to improve hydrolytic enzyme activity, the application of nonconventional mashing procedures involving the decoction method and extrusion cooking techniques to increase the extract yield, the use of exogenous enzymes and nitrogen supplements to improve the sugar and amino acid spectra necessary for yeast fermentation, and the application of combinations of alternative grains to improve the flavor, body and foam stability of gluten-free beers.

Technological Assessment of Winter Cultivar of Common Wheat (Triticum aestivum L.) and Winter Barley (Hordeum vulgare L.) for Pale Malt Production

The study was designed to assess technological quality of grains from two wheat cultivars (Elixer and Rockefeller), as well as one cultivar of winter (Joy) and one cultivar of spring barley (Irina), and to carry out the malting process at temperature of 15°C for 5 days. Malt analyses were carried out in accordance with the ECB Methods. The wheat malts were found with lower Kolbach index, and high viscosity was identified in wort obtained from wheat. The findings related to the wheat malts showed better quality parameters in Elixer variety compared to Rockefeller variety. Elixer wheat malt had higher diastatic power (427.03 WK) and lower extractivity (81.85%) compared to Joy barley malt (376.12 WK and 85.79%). Laboratory tests assessing the malts and wort showed that winter barley grain has high malting quality and can be used without modifications in the malting and mashing processes in brewing industry. It is necessary to conduct further research focusing on cultivation, agricultural techniques and technologies applied in wheat farming, in order to obtain cultivars which can be used to produce high quality malts.

The Influence of Partial Substitution of Malt with Unmalted Wheat in Grist on Quality Parameters of Lager Beer

The aim of this research was to assess whether the grist mixture (50% malt, 34% maize grits, and 16% unmalted wheat) used for the production of beer 1 could be appropriate for lager to retain the declared quality and colloidal stability during the commercial shelf life (6 months) in regards to beer 2 produced completely out of barley malt. Raw materials, worts, and beers were analyzed before and after production and over the period of 6-month storage. All analyses were done in accordance with the European Brewery Convention methods. Beer 1 resulted in a more desirable wort composition considering the total, high molecular weight (HMW) proteins, and viscosity. Beer 1 had less total proteins and polyphenols, lower viscosity and color, and higher starting clarity than beer 2. Haze measurements showed that even though beer 1 had lower starting haze, it resulted in significantly less colloidal stability during the storage of 6 months, in comparison to beer 2. The results indicate that the production of light lager beer using unmalted wheat in grist could be acceptable for colloidal stability only if such beer is to be stabilized by operations that ensure the removal of haze inducers (primarily haze active proteins).

Leveraging endogenous barley enzymes to turn lactose-containing dairy by-products into fermentable adjuncts for Saccharomyces cerevisiae-based ethanol fermentations

Acid whey, a by-product of strained yogurt production, represents a disposal challenge for the dairy industry. Utilization schemes are currently limited; however, acid whey contains valuable components that could be used to create value-added products. One potential scheme would be the fermentation of acid whey into an alcoholic beverage. Sour beers are gaining popularity and acid whey, which is sour to begin with, could provide a new product opportunity. However, the main sugar of acid whey, lactose, cannot be fermented by the traditional brewer's yeast, Saccharomyces cerevisiae. It has been reported that barley contains enzymes capable of hydrolyzing lactose to glucose and galactose, which are fermentable by S. cerevisiae. We investigated whether a barley-based mash resulted in detectable hydrolysis of lactose into sugars fermentable by S. cerevisiae. We demonstrated the ability to hydrolyze lactose in acid whey using a barley-based mash, resulting in the average release of 3.70 g/L of glucose. Additionally, the subsequent liquid was fermented by S. cerevisiae to an average ethanol concentration of 3.23% alcohol by volume. This work demonstrates the ability to hydrolyze the lactose in acid whey using barley and the opportunity to use acid whey as a fermentable sugar source in beer production.

BASIC INGREDIENTS AND THEIR ANALYSIS DURING THE FORMATION OF BEER QUALITY

The analysis and comparative description are carried out of varieties of brewing barley light malt and type 90 hops from domestic and foreign producers, as the main plant raw material that forms the quality of beer. The quality indexes of malt samples and hop pellets have been tested for compliance with applicable standards.The obtained results indicate that the varieties of barley malt are homogeneous grain mass, do not contain moldy and damaged grains, weed impurities, have a color from light yellow to gray to yellow. Ten samples of malt of various grades for beer production have been studied in terms of mass fraction of moisture (3.2–3.7%), mass fraction of extract in dry matter of fine malt (82.4–87.5%), degree (0 9–1.2%), the mass fraction of protein substances in dry matter of malt (9.1–10.1%), the Kolbach index (39.1–40.2%), the amount of nitrogenous substances (0.70–0, 74%). It has been established that the quantitative content of β-glucans significantly differs in different varieties: the minimum amount is contained in the malt Château Wien, the maximum is Pilsner Weyermann and Munich.According to the research results, it has been established that barley malt varieties have a pronounced malt aroma and sufficient fermentative activity and can serve as the base in the mash in the production of beer. It is proved that malt samples have an acceptable amount of toxic substances and radionuclides that will not affect the quality of the finished product. In assessing the quality of varieties of hop pellets by organoleptic indicators, the mass fraction of moisture and α-acids, it is established that the samples have the values of the indicators within the permissible limits. The samples have a cylindrical shape of different hues and approximately the same size; pure hop aroma, without an off-aroma; the color on the surface and at the boundary of the pellets meets the requirements of the standard. The mass fraction of α-acids is in the range from 3.0 to 12.7 %. It is revealed that bitter and aromatic hops are used for pellet production. The samples Magnym and Hallertau Perle are classified as bitter varieties. Hop pellets of the varieties Premiant and Sladek are bitter and aromatic.According to the results of the determination of quality indicators, the following ones have been identified as the best: malt – Munich, Pilsner, Carabohemian, hop pellets – Bramling Cross, Mandarina Bavaria and Magnym. The proposed varieties of malt and hops allow obtaining beer with high organoleptic characteristics, colloidal stability and expand the range of the industry by creating new varieties to meet the needs of the consumer.

Assessment of Beer Quality Based on a Robotic Pourer, Computer Vision, and Machine Learning Algorithms Using Commercial Beers

Sensory attributes of beer are directly linked to perceived foam-related parameters and beer color. The aim of this study was to develop an objective predictive model using machine learning modeling to assess the intensity levels of sensory descriptors in beer using the physical measurements of color and foam-related parameters. A robotic pourer (RoboBEER), was used to obtain 15 color and foam-related parameters from 22 different commercial beer samples. A sensory session using quantitative descriptive analysis (QDA^® ) with trained panelists was conducted to assess the intensity of 10 beer descriptors. Results showed that the principal component analysis explained 64% of data variability with correlations found between foam-related descriptors from sensory and RoboBEER such as the positive and significant correlation between carbon dioxide and carbonation mouthfeel (R = 0.62), correlation of viscosity to sensory, and maximum volume of foam and total lifetime of foam (R = 0.75, R = 0.77, respectively). Using the RoboBEER parameters as inputs, an artificial neural network (ANN) regression model showed high correlation (R = 0.91) to predict the intensity levels of 10 related sensory descriptors such as yeast, grains and hops aromas, hops flavor, bitter, sour and sweet tastes, viscosity, carbonation, and astringency.

PRACTICAL APPLICATIONS

This paper is a novel approach for food science using machine modeling techniques that could contribute significantly to rapid screenings of food and brewage products for the food industry and the implementation of Artificial Intelligence (AI). The use of RoboBEER to assess beer quality showed to be a reliable, objective, accurate, and less time-consuming method to predict sensory descriptors compared to trained sensory panels. Hence, this method could be useful as a rapid screening procedure to evaluate beer quality at the end of the production line for industry applications.

Proteomics, peptidomics, and immunogenic potential of wheat beer (Weissbier)

Wheat beer is a traditional light-colored top-fermenting beer brewed with at least 50% malted (e.g., German Weissbier) or unmalted (e.g., Belgian Witbier) wheat (Triticum aestivum) as an adjunct to barley (Hordeum vulgare) malt. For the first time, we explored the proteome of three Weissbier samples, using both 2D electrophoresis (2DE)-based and 2DE-free strategies. Overall, 58 different gene products arising from barley, wheat, and yeast (Saccharomyces spp.) were identified in the protein fraction of a representative Weissbier sample analyzed in detail. Analogous to all-barley-malt beers (BMB), barley and wheat Z-type serpins and nonspecific lipid transfer proteins dominated the proteome of Weissbier. Several α-amylase/trypsin inhibitors also survived the harsh brewing conditions. During brewing, hundreds of peptides are released into beer. By liquid chromatography-electrospray tandem mass spectrometry (LC-ESI MS/MS) analysis, we characterized 167 peptides belonging to 44 proteins, including gliadins, hordeins, and high- and low-molecular-weight glutenin subunits. Because of the interference from the overabundant yeast-derived peptides, we identified only a limited number of epitopes potentially triggering celiac disease. However, Weissbier samples contained 374, 372, and 382 ppm gliadin-equivalent peptides, as determined with the competitive G12 ELISA, which is roughly 10-fold higher than a lager BMB (41 ppm), thereby confirming that Weissbier is unsuited for celiacs. Western blot analysis demonstrated that Weissbier also contained large-sized prolamins immunoresponsive to antigliadin IgA antibodies from the pooled sera of celiac patients (n = 4).

Simultaneous sampling of volatile and non-volatile analytes in beer for fast fingerprinting by extractive electrospray ionization mass spectrometry

By gently bubbling nitrogen gas through beer, an effervescent beverage, both volatile and non-volatile compounds can be simultaneously sampled in the form of aerosol. This allows for fast (within seconds) fingerprinting by extractive electrospray ionization mass spectrometry (EESI-MS) in both negative and positive ion mode, without the need for any sample pre-treatment such as degassing and dilution. Trace analytes such as volatile esters (e.g., ethyl acetate and isoamyl acetate), free fatty acids (e.g., caproic acid, caprylic acid, and capric acid), semi/non-volatile organic/inorganic acids (e.g., lactic acid), and various amino acids, commonly present in beer at the low parts per million or at sub-ppm levels, were detected and identified based on tandem MS data. Furthermore, the appearance of solvent cluster ions in the mass spectra gives insight into the sampling and ionization mechanisms: aerosol droplets containing semi/non-volatile substances are thought to be generated via bubble bursting at the surface of the liquid; these neutral aerosol droplets then collide with the charged primary electrospray ionization droplets, followed by analyte extraction, desolvation, ionization, and MS detection. With principal component analysis, several beer samples were successfully differentiated. Therefore, the present study successfully extends the applicability of EESI-MS to the direct analysis of complex liquid samples with high gas content.