Beer Color Research Articles

From Conventional to Craft Beer: Perception, Source, and Production of Beer Color-A Systematic Review and Bibliometric Analysis.

Beer is a popular beverage consumed globally, and studies have emphasized the benefits of moderate consumption as well as its sensory effects on consumers. Color is a crucial sensory attribute, being the first aspect a consumer notices when assessing a beer's quality. This review seeks to offer detailed insights into how brewing methods, raw materials, and the chemical diversity of beer influence the production of beer color. The chemical mechanisms responsible for color development and how consumers and color systems perceive the color of beer were assessed. A systematic review following the PRISMA methodology, coupled with a bibliometric analysis, was performed using (Rayyan 2022) and (VOSviewer 1.6.20) software to assess and evaluate the scientific research retrieved from the Web of Science Core Collection. The findings highlight the significant roles of malt types, heat brewing processes, control of chemical parameters, and innovative brewing techniques in conventional beer color production. Novel chromophores like perlolyrine, pyrrolothiazolate, and furpenthiazinate are thought to affect Pilsen-style beers, along with melanoidins, Strecker aldehydes, and 5-hydroxymethylfurfural (HMF) in conventional beers. In craft beers, such as fruit- or herb-based beers, flavonoids like anthocyanins, along with other natural pigments and synthetic colorants, are identified as the primary sources of color. However, studies related to the influence of chromophores like perlolyrine, pyrrolothiazolate, and furpenthiazinate on beer color are scarce, and emerging additives, such as pigments from microorganisms, spices, exotic herbs, and leaves of plants, on craft beer offer insights for future research.

The Prediction of Quality Parameters of Craft Beer with FT-MIR and Chemometrics.

Beer is one of the oldest and most known alcoholic beverages whose organoleptic characteristics are the attributes that the consumer seeks, which is why it is essential to ensure proper quality control of the final product. Fourier transform mid-infrared (FT-MIR) spectroscopy coupled with multivariate analysis can be an alternative to traditional methods to predict quality parameters in craft beer. This study aims to develop prediction models based on FT-MIR spectroscopy to simultaneously quantify quality parameters (color, specific gravity, alcohol volume, bitterness, turbidity, pH, and total acidity) in craft beer. Additionally, principal component analysis (PCA) was applied, and it was possible to classify craft beer samples according to their style. Partial least squares (PLS1) developed the best predictive model by obtaining higher R2c (0.9999) values and lower standard error of calibration (SEC: 0.01-0.11) and standard error of prediction (SEP: 0.01-0.14) values in comparison to the models developed with the other algorithms. Specific gravity could not be predicted due to the low variability in the values. Validation and prediction with external samples confirmed the predictive capacity of the developed model. By making a comparison to traditional techniques, FT-MIR coupled with multivariate analysis has a higher advantage, since it is rapid (approximately 6 min), efficient, cheap, and eco-friendly because it does not require the use of solvents or reagents, representing an alternative to simultaneously analyzing quality parameters in craft beer.

Search characteristics, online consumer ratings, and beer prices

AbstractExperience and credence characteristics are hard to assess when consumers select food products. Therefore, consumers who are unfamiliar with specific products typically use search characteristics as a proxy for product quality. As search characteristics are pivotal in consumers' decisions, we expect them to be reflected in the resulting product prices in the beer market. Besides traditional search characteristics such as beer color or fermentation type, new search characteristics such as online consumer ratings are emerging in beer markets all over the world. Thus, we use a hedonic price estimation to learn about the relative importance of traditional versus new search characteristics in the Belgian beer market. Specifically, the beer prices for 1517 different beer products of two large beer retailers are investigated to compare the role of traditional beer characteristics—color, fermentation type, beer style, origin, brewery type, and alcohol percentage—with the role of online beer ratings from the platform RateBeer.com. We find that while traditional characteristics still play a key role in the beer market, the role of online ratings seems dependent on the retail context [EconLit Citations: C36 Instrumental Variables Estimation, D83 Search—Communication, Q11 Agriculture—Prices, Q18 Food Policy].

Use of an Integrating Cavity Spectrometer to Easily Determine Beer SRM Color Without Filtration, Centrifugation or Numerical Correction

Quantification of beer color of craft unfiltered, hazy, seltzer, and fruited beer styles can be problematic due to turbidity and unconventional ingredients. A novel integrating cavity spectrometer (ICS), designed to eliminate the effect of light scatter by the sample was employed to determine if it was able to more accurately quantify beer color compared to a conventional scanning spectrophotometer (CSS). A CSS was employed to measure the absorbance and transmission of 15 filtered and unfiltered craft brewery beer samples to determine the SRM color value and tristimulus color values. The ICS measures absorbance with a 430 nm LED to determine the single-point SRM value for each beer. The SRM values of unfiltered or 0.2 µm filtered beer samples were compared using Bland-Altman analysis and regression fits. Filtered and very clear beers showed strong agreement between the methods and Bland-Altman analysis confirmed their equivalence, particularly for SRM <25. Using the ICS alone, filtered beer versus unfiltered beer showed highly correlated values and narrow limits of agreement, successfully negating the effects of turbidity. In conclusion, SRM determination by ICS is equivalent to standard spectrophotometer single-point methods and superior in accurately determining the SRM color of hazy beers without filtration or centrifugation.

Experimental Study and Modeling of Beer Dealcoholization via Reverse Osmosis

The goals of the present investigation are to study and to model pale lager beer dealcoholization via reverse osmosis (RO). Samples were dealcoholized at a temperature of 15 ± 1 °C. An Alfa Laval RO99 membrane with a 0.05 m2 surface was used. The flux values were measured during the separations. The ethanol content, extract content, bitterness, color, pH, turbidity, and dynamic viscosity of beer and permeate samples were measured. The initial flux values were determined using linear regression. The initial ethanol flux (JEtOH 0) values were calculated from the initial flux values and the ethanol content values. A 2P full factorial experimental design was applied, and the factors were as follows: transmembrane pressure (TMP): 10, 20, 30 bar; retentate flow rate (Q): 120, 180, 240 L/h; JEtOH 0 was considered as the response. The effect sizes of the significant parameters were calculated. The global maximum of the objective function was found using a self-developed Grid Search code. The changes in the analytical parameters were appropriate. The TMP had a significant effect, while the Q had no significant effect on the JEtOH 0. The effect size of the TMP was 1.20. The optimal value of the factor amounted to TMP = 30 bar. The predicted JEtOH 0 under the above conditions was 121.965 g/m2 h.

Gluten reduction in beer: Effect of sorghum:quinoa ratio and protein rest time on brewing parameters and consumer acceptability

The combined effects of the grist composition (sorghum:quinoa ratio) and mashing conditions (protein rest time) were investigated with the aim to reduce gluten content in beer and to evaluate their impact on the physicochemical parameters and consumers' acceptability of final beer. Principal Component Analysis results, which explained 72.65% of data variability, showed a good separation of beer samples according their grist composition. Using high sorghum concentrations (34 and 40%) led to a significant reduction (p < 0.05) in extract, Free Amino Nitrogen (FAN), alcohol, total nitrogen content and the colour of the final beer. Protein rest time showed a significant impact on the sensory attributes of beer samples; therefore, it should not exceed 30 min. Beer with the best brewing performance in terms of physicochemical attributes and consumers’ preference (considered as “like moderately” by 90 consumers) was formulated with 6 and 34% of unmalted sorghum and quinoa, respectively, and by performing 20 min of protein rest. Results from this study suggested that the use in brewing of unmalted sorghum and quinoa, in an optimized combination, allows to develop beer brewed with unconventional grains without adversely affect consumer acceptance and purchase intention.

Multi-Response Optimization of the Malting Process of an Italian Landrace of Rye (Secale cereale L.) Using Response Surface Methodology and Desirability Function Coupled with Genetic Algorithm.

Rye is used in some applications in the food and beverage industry and for the preparation of functional foods. It is an interesting raw material in malting and brewing due to its characteristic contribution to the beer's color, turbidity, foam and aroma. The aim of this work was to optimize the micro-malting process of a rye landrace. The response surface methodology (RSM) was applied to study the influence of three malting parameters (germination time, germination temperature and degree of steeping) on the quality traits of malted rye. Long germination times at high temperatures resulted in an increase in the extract and Kolbach index. The model for the apparent attenuation limit showed a particular pattern, whereby time and temperature inversely influenced the response. The lowest viscosities were determined in the worts produced from highly modified malts. Optimization of the variables under study was achieved by means of a desirability function and a genetic algorithm. The two methodologies provided similar results. The best combination of parameters to optimize the malting process on the rye landrace under study was achieved at 6 days, 12 °C and 44 g/100 g.

Assessing the influence of colour and glass type on beer expectations

We evaluated how beer colour and glass type interact when it comes to forming beer expectations. Following previous research, we predicted that, given that colour is a dominant feature in food and beverage expectations, it would modulate the effects of glass type on beer expectations. One hundred and ninety-five participants from the United Kingdom took part in the experiment, which followed a 6 × 7 within-participants experimental design, with factors glass type (Pilsner, Pint, Tulip, Chalice, Weissbier, and Mug) and colour (yellow, blue, brown, orange, black, red, and green). Our results revealed that whilst colour influenced the expectations-based sensory-discriminative, hedonic, and willingness to pay (WTP) ratings, glass type influenced all variables but intensity and WTP. Importantly, all the variables for which glass type had a main effect were followed by a significant interaction. The results indicate that, the extent to which an extrinsic beer element, namely glass, influences expectations, depends on the associations that people have with colour, an intrinsic beer property closely related to beer type. We discuss the implications of our results for the design of beer expectations.

Identification of potential odorant markers to monitor the aroma formation in kilned specialty malts

Specialty malts are strategic ingredients regarding their contribution to colour and flavour of beer. Malts with the same colour may present distinct flavour characteristics and intensities. Contradictorily, colour is the benchmark in practical quality control. To investigate the correlation between colour and flavour of kilned barley specialty malts, odorants of commercial products of pale ale (5–9 EBC), Vienna (6–10 EBC), Munich (11–35 EBC) and melanoidin malts (80–90 EBC) were screened via solvent-assisted flavour evaporation (SAFE) and compared via comparative aroma extract dilution analysis (cAEDA). Subsequently, selected odorants were quantified using solid-phase microextraction (SPME). A total of 34 odorants were detected, of which 12 exhibited a concentration increase as the coloration increased, whereas 4 suggested the influence of temperature and modification degree on aroma formation. Such odorants are thus elected as potential markers for monitoring the influence of process variations on the formation of aroma in commercial kilned specialty malts.

Разработка специального сорта пива повышенной антиоксидантной активности с ягодами бузины (Sambucus nigra L.)

Fruits and berries increase the antioxidant activity of beer. Elderberries (Sambucus nigra L.) contain biologically active compounds with high antioxidant capacity. The research objective was to develop a new kind of beer with elderberries introduced at different stages of the technological process, as well as to study the antioxidant activity of this functional drink. &#x0D; The pH was determined with a pH meter, the carbohydrate content and color – with a spectrophotometer, the optical density – with a spectrophotometer, the total polyphenol content – by the Folin-Ciocalteu colorimetric method, the antioxidant activity – by the DPPH radical scavenging method, and the absorption – with a UV-visible spectrophotometer at λ = 517 nm.&#x0D; Elderberries added in the amount of 62.5 and 125 g/dm3 increased the degree of fermentation. According to the European Brewing Convention, the optimal beer color is 22.29 units. To achieve this standard, elderberries had to be added 15 min after the start of boiling the wort. When elderberries were added to the cooled wort, its color decreased by 6.97 units. The concentration of elderberries appeared to have a positive correlation with the antioxidant activity of the finished product: more elderberries meant more polyphenols. The pH did not change during the brewing process and remained within the standard limit of 4.25–4.81. When the concentration of elderberries was 1.25 g/dm3, the antioxidant activity increased by 13.4 times, at 125 g/dm3 – by 22 times. The beer reached its maximal antioxidant activity when elderberries were added to uncooled wort after boiling; it decreased by 16.1% when elderberries were added after cooling the wort. &#x0D; The content of polyphenols in elderberry beer depended on the concentration of elderberries, while the color and antioxidant capacity – on the amount of elderberries and the stage of the technological process. Unfiltered and unpasteurized elderberries maximized the antioxidant activity and nutritional value of the finished product. The new beer sort will allow microbreweries to expand their product range and attract new consumers.

Roasted Malt for Distilling: Impact on Malt Whisky New Make Spirit Production and Aroma Volatile Development

Scotch malt whisky is typically produced using lightly kilned malted barley that imparts a relatively subtle aroma to the final product. Recently, there has been increased interest in exploring the feasibility of using roasted malts during whisky production to control congener profile. Although roasted malts are used widely within the brewing industry to develop product color and aroma in beer, applications and challenges have not yet been established for whisky production. This study investigated a role for roasted malt as a tool to impact whisky volatile composition and the consequences of such use for production efficiency of whisky new make spirit. Pot still malt was roasted at laboratory scale (0–60 min at 80–220 °C) and incorporated into a grist (≤50% w/w) for production of new make spirit. The influence of roasting conditions on malt processing characteristics and the impact on the concentration of key roasted malt volatile compounds in distillate were assessed using response surface modelling. Concentration of aroma active pyrazines and furans increased in the distillate produced using roasted malts (particularly when using malt heated >150 °C). Key indicators of process efficiency such as wort fermentability and alcohol yield reduced as intensity of malt roasting increased. Process efficiency when using low proportions of roasted malt (10% w/w) was comparable to that when using only pot still malt, but distillate volatile profile still differed significantly.

How sensory and hedonic expectations shape perceived properties of regular and non-alcoholic beer

While the popularity of reduced alcohol beer has been increasing, consumers still sometimes complain about perceived sensory defects of these beverages. Breweries are working to improve the sensory profile of low and non-alcoholic beers by changing the product formulation, however, here we wanted to investigate the impact of psychological, rather than chemosensory determinants of flavour perception and consumer experience. As the way we experience the world around us, including gustatory perception, is shaped by our expectations, we investigated and modelled the relationships between product-related cues, expectations, and perception. We tested 87 regular beer drinkers to examine whether and how beer colour, label-based sensory descriptors and labelled alcohol content affect expected and perceived bitterness, refreshment, liking and body. Additionally, we wanted to establish, using mediation analysis, whether expectation mediate these effects. In summary, we found that both beer colour and under some circumstances sensory descriptors can shape consumers’ perception of beer taste, flavour, and mouthfeel. However, liking of beer was only influenced by labelled and actual alcohol content, not by beer colour or sensory descriptors. Finally, we have demonstrated that expectations act as a mediator, transferring the effect of intrinsic (beer colour) and extrinsic (labelled alcohol content and sensory descriptor) product cues to shape consumer sensory experience.

Quality changes of HomChaiya rice beer during storage at two alternative temperatures

A newly developed HomChaiya rice beer has several nutritional advantages and phytochemical benefits. However, the quality after prolonged storage is not yet known. The present study explored the quality changes of HomChaiya rice beer stored in glass bottles at two temperatures (4°C for low and 25°C for ambient) for an extended period (12 months). The beer was analyzed for physiochemical quality, phytochemicals, and antioxidant activity at one-month (30 days) intervals. Prolonged storage under ambient temperature slightly darkened the beer color. The CO2 level in the stored beer was higher in ambient storage. The pH decreased with storage time, and acidic pH was noted for the beer in ambient storage. The alcohol content increased throughout the storage at both tested temperatures. Foam stability and density increased during storage, whereas viscosity and turbidity decreased. Free amino acids and total nitrogen gradually increased, and they were slightly higher in samples stored under the ambient storage. Total phenolic content was higher in beer in ambient storage, and conversely, the total flavonoids were higher in beer stored in the refrigerator. Overall, this study found that the HomChaiya rice beer is highly suitable for extended storage at low to ambient temperatures.

Assessment of Staling Aldehydes in Lager Beer under Maritime Transport and Storage Conditions.

Beer flavor stability is greatly influenced by external temperature, vibrations, and longer delivery times. The present study assessed the impact of transport and storage conditions on staling aldehyde evolution in lager beers across five sample groups (fresh, transport, and storage simulation, and their controls), which differed in their bottle opening system (either crown cap or ring pull cap). Maritime transport conditions (45 days of travel, vibrations of 1.7 Hz, and warm temperatures (21–30 °C)) were simulated, together with storage time in a distributor’s warehouse (up to 75 days). The results revealed that the concentration of Strecker aldehydes increased more quickly after transport and storage simulation in beer bottles with the ring pull cap opening system, and the contents of 2-methylpropanal and 3-methylbutanal, in particular, were up to three times higher. Benzaldehyde content also increased significantly, by 33% on average, in these samples. Hexanal was only found in beers with a ring pull cap that underwent transport simulation. Further storage after transport simulation significantly reduced the content of 2-methylpropanal, 3-methylbutanal, and hexanal, by 73%, 57%, and 43%, respectively, suggesting the formation of a bound state. 5-hydroxymethylfurfural was continuously increased by 78.5% and 40.5% after the Transport and Transport & Storage simulations, respectively. Transport conditions lead to a slight increase, of 0.6 EBC units, in beer color.

Effects of dandelion addition on antioxidant property, sensory characteristics and inhibitory activity against xanthine oxidase of beer

The effects of dandelion addition (DA) on the physiochemical properties, antioxidant activity, inhibitory activity against xanthine oxidase (XOD) and flavor of craft beer were investigated. It was found that DA changed the pH value, total acid content, thiobarbituric-acid-value, sugar content and color of beer, and increased the contents of total polyphenols and flavonoids and thus the antioxidant activity of beer. HPLC analysis showed that DA provided beer with chlorogenic, caffeic, ferulic, and chicoric acid, contributing to the inhibition activity against XOD that is a key enzyme in uric acid production. GC-MS analysis showed that 3-methyl-1-butanol, isopentyl acetate and ethyl caprylate were main aroma components of all samples. Although DA introduced the special aroma component of azulene, it did not significantly affect the appearance, bubble, aroma and taste evaluation of beer. Conclusively, DA potentially improved the beer properties of antioxidant and inhibition of uric acid production without changing its sensory characteristics.

Comparing the efficiency of applying yeast of different generations in high gravity brewing

When fermenting beer, in addition to the formation of basic, secondary, and by-products, which largely determine the taste and aroma of the beverage, yeast is accumulated. Such yeasts can be reused in subsequent serial repitching, which allows cost savings compared to yeast cultivated for each fermentation. This paper investigates the influence of yeast generation on the progress of the wort fermentation process and the quality of beer obtained, specifically in high gravity brewing. It was established that the increase in the number of yeast generation in the range from the first to the fourth generation causes a slight acceleration of the fermentation process of high-gravity wort, while at higher values of the fermentation generation number it slows down. Yeasts secreted after six or four serial wort fermentations with a gravity of 15 °P/18 °P, respectively, have a good physiological state and can be reused. The yeast generation number does not significantly affect ethanol content and sensory beer quality indicators. However, the use of yeast of the seventh and eighth generation causes a slight increase in the pH and color of high gravity beer, the appearance in the aroma of noticeable extraneous shades ‒ yeast tone, tone of young beer. As wort gravity increases, the number of yeast re-use cycles decreases, which is a consequence of the influence of various stress factors, specifically high osmotic pressure, and increased ethanol levels. Therefore, for the fermentation of wort with a gravity of 15 °P, it is recommended to use yeast up to five generations, for 18 °P wort ‒ to four generations. To obtain beer with appropriate physicochemical parameters and high sensory evaluation in high gravity brewing technology, it is advisable to ferment wort with a gravity of 15 °P with yeast for up to five generations.

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.

English

The quality and the composition and of the beer is not only depend on the qualities of the raw materials used, but also on the technology used to make it. Each and every brewing step plays an important role in quality of final product. The aim of our study was to investigate the effect of changes in profiles of mashing and wort boiling on the final beer. It was observed that change in mashing steps greatly influences the extract content and prolonged boiling lead to increase in color and bitterness of final beer.

The effect of different oat (Avena sativa L) malt contents in a top-fermented beer recipe on the brewing process performance and product quality

In brewing, barley (Hordeum vulgare L.) malt is increasingly being replaced by other cereals. This stems from the desire to add new characteristics to beer and/or to improve the brewing process or cost of production. This research aimed to analyse the effect of different percentage shares (0, 10, 50 and 100 %) of oat (Avena sativa L.) malt in the recipe on the course of top-fermented beer production. The analysis conducted did not show any negative effect of the application of 10 % share of oat malt in the recipe on the brewing process and the quality of the final product, as compared to the no-oat-malt recipe. On the other hand, in the case of higher oat malt content, prolongation of lautering time (up to ca. 120 min), lower quantity of wort (up to ca. 30 %), its extract content (up to ca. 35 %), and thus alcohol concentration, as well as intensified colour of beer were observed. In oat and barley beers, the content of D-chiro-inositol was below the detection threshold, while small amounts of myo-inositol were determined in the samples. Furthermore, the application of oat malt affected the ionic content of the wort and did not affect the level of phenolic compounds.

Gas-Diffusion Microextraction (GDME) Combined with Derivatization for Assessing Beer Staling Aldehydes: Validation and Application.

In this work, a gas-diffusion microextraction (GDME) methodology was optimized and validated for the analysis of selected staling aldehydes (furfural (FURF), 2-methylpropanal (2-MP), 2-methylbutanal (2-MB), 3-methylbutanal (3-MB), and acetaldehyde (ACET)) during natural and forced aging of beer. The methodology was optimized considering time, temperature of extraction, and derivatizing agent. Using 4-hydrazinobenzoic acid (HBA) as a derivatizing agent, the performance of the method was evaluated by assessing several parameters such as detection limits (ranging from 1.2 to 1857.7 µg/L for 2-MB and ACET, respectively), quantification limits (ranging from 3.9 to 6192.4 µg/L for 2-MB and ACET, respectively), recoveries (higher than 96%), intraday and interday precisions (lower than 3.4 and 9.2%, respectively), and linearity (r2 ≥ 0.995). During beer aging, higher content of Strecker aldehydes and FURF were found, while no significant variations in ACET levels were observed. In general, the aldehydes content assessed for beers stored at 37 ± 1 °C for 7 and 14 days mimics that observed for beers stored at 20 ± 2 °C for 3 and 6 months, respectively. Lower temperatures of storage (4 ± 1 °C) delayed the development of staling aldehydes. Based on PCA analysis, the content of staling aldehydes and beer color were responsible for 91.39% of the variance among the analyzed samples, and it was demonstrated that these are key parameters to discriminate fresh from aged beers. The results herein presented showed that the proposed analytic methodology is a valuable strategy for the characterization and quantification of important staling aldehydes in beer with a potential application in the quality control of beer during storage.