Beer Storage Research Articles

Quantitation of Key Antioxidants and Their Contribution to the Oxidative Stability of Beer.

A sensitive high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MSMRM) method, leveraging both technique and internal calibration, was developed for the simultaneous and comprehensive quantitative analysis of 46 antioxidants and antioxidant precursors in different beer types without any cleanup procedure. Combined with their in vitro antioxidant activity, a dose-activity estimation exposed a group of 10 key antioxidants, namely, tryptophan, tyrosine, hordatine A, hordatine B, procyanidin B3, prodelphinidin B3, tachioside (3-methoxy-4-hydroxyphenyl-β-d-glucopyranoside), (+)-catechin, tyrosol, and ferulic acid. To study the effect of antioxidants in spiking and aging studies, another liquid chromatography-MS (LC-MS)-based method was developed, monitoring markers for oxidation in beer. A positive effect of the antioxidants on the flavor stability at naturally relevant concentrations was shown by a slowing of oxygen-dependent aging reactions highlighted in beer storage trials under oxygen atmosphere. Thereby, a doubling of the natural concentration of all investigated antioxidants in beer revealed a limit inhibition of 67% on the degradation of cis-isocohumulone to hydroxy-cis-alloisocohumulone.

The spoilage of lager by draught beer microbiota

Why was the work done: To determine whether the susceptibility of lager to microbiological spoilage is determined by composition, microbiota or both. To assess beer spoilage by a consortium of yeasts and bacteria from draught beer rather than pure laboratory cultures. How was the work done: Four draught beer styles - cask ale and keg lager, ale, and stout – were sampled twice in five different public houses in four different locations. The beers were forced by static incubation at 30°C for four days. ‘Challenge testing’ with an inoculum of heterogeneous microorganisms from the forced samples was used to assess the spoilage of ten commercial lagers by the increase in turbidity at 660 nm. The same approach was used to evaluate the role of nutrients in beer spoilage by forcing with the addition of yeast extract or vitamins (thiamine and riboflavin). What are the main findings: The ten lagers varied in susceptibility to spoilage ranging three-fold from the least to most spoilable. Average spoilage of the beers was comparable for microorganisms from lager, keg ale and stout but ca. 50% greater with microorganisms from cask ale. The ranking of spoilage of the 10 lagers was similar for microbiota from cask ale, keg ale and stout but less so from lager. Spoilage was influenced by beer composition and was inversely related to beer pH and level of free amino nitrogen. The addition of yeast extract stimulated spoilage of the least spoilable lager but the addition of vitamins B1 and B2 had little or no effect. Spoilage was extensive at 30°C, measurable at 12°C but imperceptible at 2°C. Why is the work important: The oft-quoted statement that beer is ‘robust to microbiological spoilage’ is a fallacy. All ten lagers were spoilt by draught beer microorganisms, but some were more spoilable than others. It is suggested that spoilage may be reduced by lowering beer pH and curbing the availability of nutrients for microbial growth. Whilst (as would be expected) beer storage at 2°C suppresses microbial growth, storage at 12°C (as practiced in UK public house cellars) allows spoilage microorganisms to grow in beer. Although the threat of microbial spoilage in the brewing process is managed by good manufacturing practices, draught beer is vulnerable and requires more focus and commitment to hygienic practices to assure quality.

Effect of Wort Boiling System and Hopping Regime on Wort and Beer Stale-Flavor Aldehydes.

The main factor responsible for the sensory aging of beer is the increase in off-flavor aldehydes during beer storage. In pilot brews (200 L) of pale lager beer with different hopping regimes and wort boiling systems, 15 carbonyls were monitored using the GC-MS method. Factor analysis revealed several groups of aldehydes with similar behavior during wort boiling. The concentration of most of them decreased with atmospheric wort boiling and increased with the time and energy-saving pressurized boiling system. Wort clarification was a critical step because of the increase in carbonyl concentration, with the level of most carbonyls being higher in the final wort compared to sweet wort. The hopping regimes only affected the level of 3-methylbutan-2-one in the wort. The concentration of carbonyls decreased significantly (30-90%) during fermentation, except for trans-2-butenal, which increased by 59% on average, likely due to the release from imine complex. The concentration of free aldehydes in the fresh beers was similar for all variants used, but the pressurized wort boiling system could result in lower sensory stability of the beer due to the release of aldehydes from inactive complexes formed during fermentation. This aspect requires further investigation.

The Effect of Mash-In Temperature on the Characteristics and Flavor Stability of Pilsner-Type Beer

Beers were brewed at mash-in temperatures of 35 °C, 50 °C, and 65 °C, and their flavor profiles and stability were examined. Beers with mash-ins at 35 °C and 50 °C exhibited full-bodied taste and estery sensory qualities with higher concentrations of esters and amino acids. Higher extract yields were obtained in wort with mash-ins at 35 °C and 50 °C, the optimal temperatures for enzymes to break down the tissue where starch granules are located. In contrast, the beer with a 65 °C mash-in temperature had a light taste and a toast-like aroma. In terms of providing nutrition for the yeast, the proteolytic process to produce amino acids seemed unnecessary for brewing beer made exclusively from malt. Following a month of storage at 30 °C, cardboard flavors predominated in beers with mash-in temperatures of 35 °C and 50 °C, while honey and sherry-like scents predominated in beers with a mash-in temperature of 65 °C. The concentrations of the 14 components contributing to the stale flavor of Pilsner-type beers, including Strecker aldehydes, did not correlate with mash-in temperature, with the exception of the concentration of (E)-2-nonenal, even though the mash-in temperatures were predicted to affect the formation of Strecker aldehydes during beer storage.

Why Catechin and Epicatechin from Early Hopping Impact the Color of Aged Dry-Hopped Beers while Flavan-3-ol Oligomers from Late and Dry Hopping Increase Colloidal Instability

Dry hopping imparts distinct aromas but also a series of non-volatile compounds suspected of causing flavor and physical instability during beer storage. In this work, color, chill haze, total polyphenols, total flavanoids, and flavan-3-ol monomers (catechin and epicatechin) and oligomers (procyanidin dimers and trimers) were monitored in five commercial pale-colored Belgian dry-hopped beers over 24 months of storage at 20 °C in the dark. Fresh dry-hopped beers contained unusually high levels of flavan-3-ol monomers (up to 6.6 mg/L) and oligomers (up to 14.1 and 10.2 mg/L dimers and trimers, respectively). The increase in color intensity during storage (up to 6.4°EBC) correlated with fresh beer monomer levels, while the oligomer content correlated with chill haze formation (up to 25.7°EBC). The evolution of these two physical attributes also correlated with the level of total polyphenols in the fresh beers. In a pilot-scale production, kettle hopping was shown to impart either monomers (early) or oligomers (late), while dry hopping promoted efficient extraction of both monomers and dimers (extraction yields of 62 and 74%, respectively). Dry hopping thus plays an important role in color and chill haze increase.

Effect of Moringa stenopetala leaf extracts on the physicochemical characteristics and sensory properties of lagered beer.

Flavor instability resulting from beer storage and oxidation is the most important quality‐related problem in the brewing industry. This study evaluated the influence of adding 80% ethanolic extract of Moringa stenopetala leaf to lagered beer at 400, 600, and 800 ppm concentrations for 30‐, 60‐, and 90‐day storage time at room temperature. The effect of physicochemical properties of the beer incorporated with leaf extract of Moringa stenopetala (LEMS) was evaluated using the American Society of Brewing Chemists method of analysis. Sensory acceptability of the beer treated with LEMS was evaluated using nine hedonic scales over a period of storage time. Original gravity (11.06–11.08), apparent extract (3.68–3.77), pH (4.23–4.40), vicinal diketone (0.07–0.09), and alcohol content (4.76–4.81) were not altered by the incorporation of LEMS at any level of treatment and over a period of storage time. The beer color (8.88–9.70 EBC), bitterness (13.62–15.56 bitterness unit), calcium ion (44.18–52.04 ppm), and foam stability (201.5–246.5) of beer increased with increasing LEMS concentration, but a significant haziness reduction (1.23–0.63) was observed. However, the storage time decreased both haziness and foam stability of LEMS‐incorporated beer. The incorporation of LEMS at an optimum level kept its quality for 90 days better than the usual antioxidant (potassium metabisulfite) added in beer. The sensory analysis also supported the beer treated with 600 ppm of LEMS as the best overall acceptability. The result indicates a promising use of LEMS as a functional ingredient in beer to reduce beer oxidation probability and keep its freshness for a period of storage time.

The biogenic amine-producing bacteria from craft beer and their kinetic analysis between growth characteristics and biogenic amine formation in beer.

Craft beer because of its fresh flavor, unique taste, and rich nutrition is becoming more popular to consumers. Compared with industry beer, craft beer is often nonfiltered and nonpasteurized, for this reason, it has a short shelf life and is more susceptible to microbial spoilage, which may cause the quality deterioration of craft beer and the formation of biogenic amine as a harmful factor for consumer's health. In this study, the 23 beer-spoilage bacteria were isolated from craft beer, which were identified as 15 Lactobacillus (L.) brevis, 3 L. plantarum, 1 L. parabuchneri, 2 L. paracasei, and 2 Pediococcus damnosus. Among 23 beer-spoilage isolates, 20 representatives were able to form tyramine, histamine, putrescine, cadaverine, and/or tryptamine in MRS broth. The nine Lactobacillus strains were incubated in beer and produced tyramine, histamine, putrescine, cadaverine, and/or tryptamine during beer storage process. Logistic and Gompertz model could be adopted to respectively describe the kinetics of microorganism growth and biogenic amine formation. The relationship between the biogenic amines and biomass was simulated by Luedeking-Piret model very well, and showed that the formation of biogenic amine was mainly bacteria growth-associated in beer. These findings may be helpful for finding the preventive measures to control biogenic amine formation and for enhancing the safety of craft beer. PRACTICAL APPLICATION: The selection of the biogenic amine-producing spoilage bacteria from craft beer and the investigation their kinetics of the growth and biogenic amines production under beer environmental conditions was very helpful for finding preventive measures to eliminate or reduce biogenic amine formation and for appropriate increase in food safety.

Impact of temperature during beer storage on beer chemical profile

Aiming to gain insights into the impact of storage conditions on the chemical profile of beer samples, changes on the relative amount of several chemical classes of compounds was monitored. The influence of storage conditions was statistically discerned using the hierarchical cluster analysis complemented by heatmap date visualization. Aldehydes, furanic compounds and esters showed a clear role in beers stored at 37 ± 1 °C (contribution >1, as obtained in the heatmap data visualization). The reaction rate constant and temperature dependence was well described by the Arrhenius equation for these compound classes, for which the reaction rate increased with increasing temperatures. The rate of development of furanic compounds, aldehydes and esters showed to be almost 140, 90 and 20 times higher in beers stored at higher temperatures (37 ± 1 °C) when compared to beers stored at 4 ± 1 °C, respectively. These results indicate that temperature was the main parameter contributing to the major changes in beer chemical profile. Through olfactometric analysis, the major difference was found in aged beers, both naturally and forced aged, where the prevalence of sweet and papery aroma notes were noticed, linked to the development of β-damascenone and E-2-nonenal, respectively.

Cervejas: relação entre estilos; compostos fenólicos e capacidade antioxidante

Na composição química da cerveja são encontrados compostos fenólicos que contribuem para suas características sensoriais e possuem capacidade antioxidante, auxiliando a manutenção da estabilidade oxidativa. A compilação de 35 estudos, publicados entre 2006 e 2020, teve o objetivo de levantar informações a respeito dos compostos fenólicos e da atividade antioxidante de cervejas e relacionar os resultados obtidos com os tipos de cervejas analisadas. Os resultados mostraram que, tanto o teor quanto o perfil de compostos fenólicos e a atividade antioxidante da cerveja, sofrem influência dos ingredientes utilizados e do processo de fabricação. As cervejas do tipo Ale, de coloração escura, com maior amargor e teor alcóolico, apresentaram valores mais elevados de compostos fenólicos e atividade antioxidante que outros tipos e estilos. As análises para as cervejas especiais mostraram que a adição de alimentos diversificados contribuiu para melhorar a composição em bioativos da bebida. Mais de 50 compostos fenólicos já foram identificados em cervejas, derivados dos ingredientes utilizados para a fabricação. Entre os compostos fenólicos mais frequentes estão os ácidos fenólicos, como os ácidos ferúlico e caféico e catequinas. Estudos observaram estreita correlação entre o teor de compostos fenólicos totais e a capacidade antioxidante. E a presença de alguns compostos específicos pode aumentar esta atividade. No entanto, durante o armazenamento da cerveja, pode ocorrer redução da atividade antioxidante devido a mudanças nas estruturas das moléculas com essa capacidade. Estes estudos contribuem para o aprimoramento e desenvolvimento de bebidas com maior teor de compostos fenólicos, auxiliando sua estabilidade oxidativa e vida útil.

Proteomic Analysis of Hop Bitter Compound Iso-α-acid Tolerance in Beer Spoilage Lactobacillus casei 2-9-5

Lactobacillus species are the main spoilage bacteria in beer production and storage. The prerequisite for Lactobacillus species to grow in beer is to be able to resist the hop bitter compound iso-α-acid. This study examined the underlying iso-α-acid resistance mechanism of L. casei strain 2-9-5 through proteomic analysis. The significantly up-regulated proteins in L. casei 2-9-5 under 0.04% iso-α-acid are mainly involved in carbohydrate metabolism, energy generation, organic acids metabolism, and cell wall composition. Based on the proteomic analysis, it is proposed that organic acids may be important for L. casei 2-9-5 to resist iso-α-acid. The extracellular organic acids concentrations in L. casei 2-9-5 under iso-α-acid pressure were significantly higher than the control. Furthermore, additions of oxalic acid, tartaric acid, pyruvate, and ketoglutaric acid in the media were able to enhance the growth of L. casei 2-9-5 under iso-α-acid pressure. These phenomena were also observed in different Lactobacillus species, with different iso-α-acid resistance ability since the addition of organic acids also promoted the growth of these strains. Together, the data supports that organic acids are closely related to the resistance ability of Lactobacillus species towards iso-α-acid.

Fate of the mycotoxins in the wort and yeast during ale and lager fermentation and their evaluation under different technological parameters

This study aimed to evaluate the mycotoxins transfer in the wort and yeast during ale and lager fermentation, secondary fermentation, and beer storage. Four yeasts were used to ferment wort contaminated with DON and ZEN. The wort was fermented with two S. cerevisiae yeasts (yeasts A and B) at 15, 20, 25 °C for 96 h, and two S. pastorianus (yeasts C and D) at 10, 15, 20 °C for 144 h. After fermentation, the two wort with the highest mycotoxin decrease were selected for a second fermentation and stored period. Mycotoxins were extracted using QuEChERS and analyzed by UHPLC-DAD/FLD. In the wort, DON decreased from 11% to 27%, locating it adsorbed on the yeast from LOD to 6.16%. ZEN in the wort decreased from 29% to 90%, locating it adsorbed on the yeast from 5.41% to 33.86%. Ale-fermentation process obtained the highest decrease of ZEN in the wort, whereas, for DON, there was no significant difference in the reduction between the 2 fermentation styles. Finally, there was no significant change in mycotoxin content during storage. Knowledge of the mitigating effect of fermentation variables could help to reduce the mycotoxin content in beer.

Instability of Hop-Derived 2-Methylbutyl Isobutyrate during Aging of Commercial Pasteurized and Unpasteurized Ales

The current article is concerned with the instability of 2-methylbutyl isobutyrate (2-MBIB) throughout beer storage. 2-MBIB is the primary ester of hops and HS-SPME-GC-MS/MS analysis of 135 commercial ales confirmed that 2-MBIB is also one of most abundant hop-derived volatiles in ale. To investigate 2-MBIB stability during beer aging, eleven domestic ales with initial 2-MBIB levels ranging from 10 − 311 µg/L were analyzed across freshly packaged, naturally and forced aged beer. Upon storage, 2-MBIB concentrations in all ales decreased remarkably. After 24 weeks at 20 °C the tested ales lost 80% of their initial 2-MBIB concentration on average. At 4 °C, which is considered an ideal beer storage temperature, the average reduction was still 60%. Overall, the lowest 2-MBIB reduction was found in pasteurized ales, indicating that 2-MBIB decrease is driven by chemical and enzymatic reactions. The losses of 2-MBIB appear to be a significant contributor to the chemical instability of hoppy ales.

Evaluation of force-carbonated Czech-type lager beer quality during storage in relation to the applied type of packaging

The scope of the study was the evaluation of selected physicochemical parameters and organoleptic properties of Czech-type lager beer [11.00% (w/w) original wort extract; 4.60% (v/v) ethyl alcohol content] during a 12-month storage period (25 ± 2 °C), in relation to the applied type of packaging [glass bottle, aluminum can, polyethylene terephthalate (PET) bottle and stainless steel beer keg]. The examined beer samples organoleptic characteristics were off-flavors, carbonation level, fullness, bitterness intensity and overall rating. Furthermore, the examined physicochemical parameters during storage were CO2 concentration, color, turbidity (haze) and foaming stability. Generally, the type of packaging significantly influenced the physicochemical and organoleptic properties of the examined samples (P < 0.05). The more intensive changes were observed in the CO2 content, color and turbidity of the examined samples. The aluminum can and stainless steel keg were evaluated as the most suitable types of packaging for beer storage. On the contrary, the PET bottle was evaluated as the least appropriate for long-term storage period.

Effect of antioxidants on dimethyl sulphoxide reduction and impact on dimethyl sulphide formation during beer storage

Dimethyl sulphide (DMS) can be important in beer aroma. Although primarily formed during wort boiling, it can evolve during fermentation by reduction of its oxidation product dimethyl sulphoxide (DMSO). In this study, a number of antioxidants – sulphite, thiols [l-cysteine, l-glutathione (GSH)], gallic acid and ascorbic acid – were tested on DMSO reduction and DMS formation in a buffered model solution [pH 4.3, 5% (v/v) ethanol] together with a Pilsner type beer. In the model solution, significant DMSO reduction and DMS formation were observed for sulphite and the thiols l-cysteine and GSH. Ascorbic acid and gallic acid were not capable of reducing DMSO. During beer storage at 28°C, the highest DMS formation was found with the combined addition of sulphite, GSH and DMSO followed by sulphite/DMSO and GSH/DMSO. In conclusion, the reaction mechanisms of DMSO reduction and their relevance to DMS formation during beer storage are discussed. © 2018 The Institute of Brewing & Distilling

Influence of pH on the Stability of 2-Substituted 1,3-Thiazolidine-4-Carboxylic Acids in Model Solutions

Upon beer storage, the levels of staling aldehydes increase, which coincides with the appearance of characteristic off-flavors. Bound-state aldehydes have been reported as potential sources of off-flavor appearance in aging beer. This study investigated the stability of cysteinylated aldehydes, also referred to as 2-substituted 1,3-thiazolidine-4-carboxylic acids, and the release of aldehyde compounds from cysteine adducts in model solutions at different pH values that are relevant in malting and brewing. The cysteinylated aldehydes were initially synthesized for their use as reference compounds in model solutions. Confirmation of their chemical structure was obtained by 1H-NMR. The results from the stability tests showed that degradation of cysteine-bound aldehydes results in concomitant release of the free aldehydes. The rate of degradation is highly dependent on the 2-substitution pattern of the thiazolidine ring, as well as on the pH of the model solution. At malting and brewing relevant pH values (pH 4.4, 5.2, 6.0), degradation of cysteine-bound aldehydes is observed, in particular at pH 4.4, which is representative of the beer pH.

Relevance of Oxygen for the Formation of Strecker Aldehydes during Beer Production and Storage.

Off-flavor in beer is often associated with the appearance of staling aldehydes. In this study, the factors amino acid concentration, carbohydrate concentration, Fe2+ concentration, and oxygen concentration were investigated in terms of their effect on the formation of carbonyl compounds during storage using response surface methodology. From all factors tested, only amino acid concentration and oxygen concentration promoted Strecker aldehyde formation during storage, while all other carbonyls measured were unaffected. A mixture of glucose/xylose, representing carbohydrate sources, as well as Fe2+ concentration were insignificant factors, though carbohydrate additions exhibited a significant role in the formation of 2-furfural. De novo formation of phenylacetaldehyde from phenylalanine during beer storage was observed using labeling experiments and a linear relationship between Strecker aldehydes formed and total packaged oxygen was identified. Capping beers with oxygen barrier crown corks and addition of 10 mg/L EDTA to beers effectively diminished Strecker aldehyde formation. Oxygen was additionally shown to significantly promote Strecker aldehyde formation during sweet wort production. A pathway for the reactive oxygen species-induced degradation of amino acids yielding Strecker aldehydes was proposed and was further scrutinized in buffered model solutions. The insignificant role of Fe2+ in the response surface experiments is discussed.

Chemical Characterization of Beer Aging Products Derived from Hard Resin Components in Hops (Humulus lupulus L.).

The bitter taste of beer originates from resins in hops (Humulus lupulus L.), which are classified into two subtypes (soft and hard). Whereas the nature and reactivity of soft-resin-derived compounds, such as α-, β-, and iso-α-acids, are well studied, there is only a little information on the compounds in hard resin. For this work, hard resin was prepared from stored hops and investigated for its compositional changes in an experimental model of beer aging. The hard resin contained a series of α-acid oxides. Among them, 4'-hydroxyallohumulinones were unstable under beer storage conditions, and their transformation induced primary compositional changes of the hard resin during beer aging. The chemical structures of the products, including novel polycyclic compounds scorpiohumulinols A and B and dicyclohumulinols A and B, were determined by HRMS and NMR analyses. These compounds were proposed to be produced via proton-catalyzed cyclization reactions of 4'-hydroxyallohumulinones. Furthermore, they were more stable than their precursor 4'-hydroxyallohumulinones during prolonged storage periods.

Antioxidative Mechanisms of Sulfite and Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer.

The radical-mediated reactions occurring during the early stages of beer storage were studied by following the rate of oxygen consumption, radical formation as detected by electron spin resonance spectroscopy, and concentrations of the antioxidant compounds sulfite and thiols. Addition of either Fe(III) or Fe(II) had similar effects, indicating that a fast redox equilibrium is obtained between the two species in beer. Addition of iron in combination with hydrogen peroxide gave the most pronounced levels of oxidation due to a direct initiation of ethanol oxidation through generation of hydroxyl radicals by the Fenton reaction. The concentration of sulfite decreased more than the thiol concentration, suggesting that thiols play a secondary role as antioxidants by mainly quenching 1-hydroxyethyl radicals that are intermediates in the oxidation of ethanol. Increasing the temperature had a minor effect on the rate of oxygen consumption.

Possibilities to improve the antioxidative capacity of beer by optimized hopping regimes

Different hopping regimes were evaluated to investigate the effect on the oxidative stability of wort and beer. Compared with a single hop dosage at the beginning of wort boil, it was possible to increase the concentration of α-acids in pitching wort and beer by applying incremental hop dosage, dry hopping or the use of a pre-isomerized hop product in combination with an α-acid extract, which concomitantly resulted in lower iron concentrations and an enhanced flavour stability as indicated by standard wort and beer analyses, atomic absorption spectroscopy, electron spin resonance spectroscopy and sensory analysis of fresh and force-aged beers. The functional principle of hop dosage variations is explained by saving of α-acids throughout the wort production process, which yields an increased formation and precipitation of pro-oxidative acting transition metal ions (e.g. Fe) in α-acid-complexes during the whirlpool rest and fermentation. Consequently, fewer reactive oxygen species are generated. Additional laboratory trials simulating wort cooling and beer storage in buffered model solutions proved that un-isomerized α-acids are strong iron chelators and confirmed the functional principle of the applied hopping regimes. Negative effects of higher α-acid contents on fermentation performance and depletion of the zinc concentration, which is an essential nutrient for yeast, could be excluded. Copyright © 2014 The Institute of Brewing & Distilling

The influence of unmalted barley on the oxidative stability of wort and beer

The aim of this study was to investigate the influences of unmalted barley on the brewing process and the quality of the resulting beer-like beverages, with the main focus on the oxidative stability, using traditional beer analyses, GC-MS for the determination of aging compounds and electron paramagnetic resonance spectroscopy to determine free radical activity. For the investigation, brews with different barley proportions and 75% barley brews with a colour malt addition, to compensate for a lower colour using barley, were produced. In general, it can be said that beers with a proportion of up to 50% barley achieved a comparable or higher extract yield and final attenuation owing to the combined effectiveness of the malt and microbial enzymes. Although all analytical values were within the normal range according to Methodensammlung der Mitteleuropaischen Brautechnischen Analysenkommission (MEBAK), a slight decrease in total polyphenols and free amino nitrogen content was observed. Also in response to higher barley portions, an increase of higher molecular weight proteins and β-glucan was detected. Barley is not exposed to heat and oxidative stress in the malting plant, which explains the lower values of the thiobarbituric acid index and colour as an indicator of Maillard reaction products in the resulting wort and beer. Additionally, the results demonstrate a slower increase of aging compounds during beer storage with increasing barley proportions. Furthermore, it was observed that higher barley proportions led to a better oxidative stability indicated by a lower radical generation (T450-value) in wort and an increasing beverage antioxidant index/endogenous antioxidative potential (BAX/EAP value) in the final beverage. The case of ‘barley beers’ showed that the positive effect of barley on the oxidative beer stability was greater than the negative effect of the addition of colour malt, to adjust the colour of a 100% malt beer. In sensory comparison with beer produced with 100% malt, the beers brewed with a barley proportion up to 50% showed a slight flavour preference and up to a 75% equivalent evaluation. Copyright © 2012 The Institute of Brewing & Distilling