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This study investigated the activity and thermostability of α-amylase in green malt across a diverse panel of 54 barley genotypes, comprising 20 mutants, 19 hulled, 4 hulless, and 11 wild types, using starch as a substrate. The primary objective was to assess the variability in α-amylase activity among these genotypes and identify those with superior enzymatic activity and thermostability. Given that α-amylase is the most thermostable enzyme among the diastatic power enzymes yet exhibits significant activity reduction above 72.5 °C, a threshold frequently exceeded in industrial kilning and mashing. This research is therefore crucial for identifying genotypes that could enhance starch hydrolysis efficiency during mashing, a process critically dependent on sufficient enzymatic activity. We reported α-amylase activity and thermostability across a temperature range of 37 to 85 °C. The findings indicated that optimal temperature for α-amylase activity in barley malting lies between 65 and 75 °C. Interestingly, wild barley genotypes demonstrated the highest mean α-amylase activity, while hulless varieties exhibited the lowest. These results were validated by a significant negative correlation between α-amylase activity and the content of starch. Among the 54 genotypes, 11 displayed high α-amylase activity at 65 °C. Furthermore, one mutant (BL2105) and one wild genotype (WS230) exhibited high activity and thermostability at 75 °C, and another wild genotype (WS236) retained 30% of its original activity after heat treatment at 85 °C. These genotypes with enhanced α-amylase activity and thermostability could be strategically exploited in breeding programs to develop superior malt varieties. Such advancements could significantly enhance both malt quality and efficiency in beer production industry. [ABSTRACT FROM AUTHOR]

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 β-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.

Mashing is a decisive brewing step, affecting wort quality. Critical mashing parameters include time, temperature, pH, mash density and oxygen uptake. While the pH-dependent biochemical changes during mashing have been researched, the oxidative processes remain unclear. This work explores the impact of pH conditions during mashing on the biochemical composition and oxidative properties of wort. In laboratory trials, mashing was conducted at different mashing-in pH (4.5, 5.0, 5.2, 5.4, 6.0). The sweet worts were analyzed for extract, fermentable sugars, limit dextrins, amino acids, soluble proteins, polyphenols, color, aldehydes, transition metals, reducing potential, and rate of radical formation. Differences were found in enzymatic activities (particularly proteolysis), color, aldehydes, transition metal ions, the rate of radical formation and the rate of oxygen consumption. Notably, when adjusting the pH at mashing-in, the obtained wort tends to gravitate toward the pH of the unadjusted wort, underscoring its buffering capacity. This was reflected by similar properties of the produced worts, indicating pH playing a lesser role during mashing compared to time/temperature. However, under extreme acidified conditions (pH 4.5 at mashing-in), the produced wort markedly deviates. An intriguing negative correlation between the reducing potential and the content of transition metal ions with the rate of radical formation is discussed. [ABSTRACT FROM AUTHOR]

Mashing is one of the key operations in beer brewing. Together with polyphenolic compounds it can affect the quality and stability of beer. In our pilot brewing trials of pale lager (200 L), malts of three barley varieties were compared using either infusion or double decoction mashing. Total polyphenols, anthocyanogens and flavanoids were determined in sweet and hopped wort. Free phenolics were measured by HPLC coupled with coulometric detection. Antiradical power was determined by RC-DCPI, ARA-DPPH and ESR-T150 methods. In this way the influence of mashing method and barley variety on polyphenols and antiradical activity of sweet wort was demonstrated showing that the effect of mashing was stronger (ANOVA). The results showed significantly higher, i.e. by tens of per cent, levels of all polyphenols studied in both the decoction sweet wort and hopped wort. The decoction process resulted in higher levels of the antiradical power, ARA-DPPH (37–47%) and RC-DCPI (25–60%). A cluster analysis partitioned 28 free phenolic compounds in sweet wort primarily by variety and secondarily by mashing. The Malz malt showed a greater increase in polyphenols, free phenolic compounds and antiradical power in the decoction process compared to the Bojos and Sebastian malts. Decoction mashing introduces higher levels of phenolic antioxidants into the beer with the potential to improve the sensory stability of the beer and provide health benefits to the consumer. The different behaviour of malts and barley varieties needs to be better elucidated in further research.

Triticale grain, a wheat–rye hybrid, has been reported to comply very well with the requirements for modern brewing adjuncts. In this study, two triticale varieties, in both unmalted and malted forms, were investigated at various ratios in the grist, applying different mashing regimes and concentrations of the commercial enzyme Shearzyme® 500 L with the aim of evaluating their impact on wort production. In order to capture the complex relationships between the input (triticale ratio, enzyme ratio, mashing regime, and triticale variety) and output variables (wort extract content, wort viscosity, and free amino nitrogen (FAN) content in wort), the study aimed to implement the use of artificial neural networks (ANNs) to model the mashing process. Also, a genetic algorithm (GA) was integrated to minimize a specified multi-objective function, optimizing the mashing process represented by the ANN model. Among the solutions on the Pareto front, one notable set of solutions was found with objective function values of 0.0949, 0.0131, and 1.6812 for the three conflicting objectives, respectively. These values represent a trade-off that optimally balances the different aspects of the optimization problem. The optimized input variables had values of 23%, 9%, 1, and 3 for the respective input variables of triticale ratio, enzyme ratio, mashing regime, and triticale variety. The results derived from the ANN model, applying the GA-optimized input values, were 8.65% w/w for wort extract content, 1.52 mPa·s for wort viscosity, and 148.32 mg/L for FAN content in wort. Comparatively, the results conducted from the real laboratory mashing were 8.63% w/w for wort extract content, 1.51 mPa·s for wort viscosity, and 148.88 mg/L for FAN content in wort applying same input values. The presented data from the optimization process using the GA and the subsequent experimental verification on the real mashing process have demonstrated the practical applicability of the proposed approach which confirms the potential to enhance the quality and efficiency of triticale wort production. [ABSTRACT FROM AUTHOR]

In contrast to other fermented beverages, beer quality generally diminishes over time. This diminishing quality hinges heavily on the oxidative degradation of beer compounds by reactive oxygen species (ROS), whose formation is in part catalyzed by Fe(II) ions via the Fenton and Haber-Weiss reactions. Consequently, ROS accumulation throughout the brewing process results in oxidative instability and accelerates numerous beer staling reactions, like those frequently associated with the onset of unwanted flavors, aromas, and an unaesthetic appearance. However, despite its critical importance to beer stability, the oxidative state of iron in wort and finished beer continues to be poorly characterized. In this investigation, the influence of kilned specialty malt utilization on total free iron and iron ion speciation in wort was determined by EBC Method 9.13.1. Further, the reducing power of each wort was determined via 2,2-diphenyl-1-picrylhydrazyl (DPPH). Here, we demonstrate that kilned specialty malt utilization influences total iron concentration, the balance between Fe(II) and Fe(III) ion species, and the reducing power of wort. Furthermore, our results reveal a negative correlation between mash pH and total iron concentration in finished wort. These results indicate that beer's oxidative flavor stability may be improved by using lower kilned malts and adjusting mash pH. [ABSTRACT FROM AUTHOR]

Mashing is one of the key operations in beer brewing. Together with polyphenolic compounds it can affect the quality and stability of beer. In our pilot brewing trials of pale lager (200 L), malts of three barley varieties were compared using either infusion or double decoction mashing. Total polyphenols, anthocyanogens and flavanoids were determined in sweet and hopped wort. Free phenolics were measured by HPLC coupled with coulometric detection. Antiradical power was determined by RC-DCPI, ARA-DPPH and ESR-T150 methods. In this way the influence of mashing method and barley variety on polyphenols and antiradical activity of sweet wort was demonstrated showing that the effect of mashing was stronger (ANOVA). The results showed significantly higher, i.e. by tens of per cent, levels of all polyphenols studied in both the decoction sweet wort and hopped wort. The decoction process resulted in higher levels of the antiradical power, ARA-DPPH (37-47%) and RC-DCPI (25-60%). A cluster analysis partitioned 28 free phenolic compounds in sweet wort primarily by variety and secondarily by mashing. The Malz malt showed a greater increase in polyphenols, free phenolic compounds and antiradical power in the decoction process compared to the Bojos and Sebastian malts. Decoction mashing introduces higher levels of phenolic antioxidants into the beer with the potential to improve the sensory stability of the beer and provide health benefits to the consumer. The different behaviour of malts and barley varieties needs to be better elucidated in further research. [ABSTRACT FROM AUTHOR]

Consumers are more than ever in search of novel and exciting beer choices, and brewers are, therefore, continuously experimenting to adapt their product portfolio. One interesting way to naturally incorporate novel flavors and tastes is by using alternative adjuncts, but this is not always an easy and straightforward process. In this study, a 40% unmalted alternative adjunct (einkorn, emmer, spelt, khorasan, quinoa, amaranth, buckwheat, sorghum, teff, and tritordeum) or reference (barley malt, unmalted barley, and unmalted wheat) was added to 60% barley malt, after which three different laboratory mashing processes (Congress mash, Congress mash with pre-gelatinization of the adjunct, and Evans mash) were performed, and their behavior during mashing and the resulting wort characteristics were investigated in detail. Overall, the extraction process of all 10 unmalted alternative adjuncts was not complete for all three laboratory mashing processes, whereby Congress mashing resulted in the highest extract and fastest filtration, whereas Evans mashing resulted in the lowest extract and slowest filtration. Pre-gelatinization of the unmalted was generally only beneficial for adjuncts with high onset starch gelatinization temperatures. This process also inactivated endogenous enzymes in the unmalted adjuncts, which had an adverse effect on the mashing process. [ABSTRACT FROM AUTHOR]

Beer ranks third in terms of consumption worldwide, and its technology is constantly being improved and perfected. The boom in craft brewing has led to the production of thousands of new types of beer, but most often without scientific justification of the technological decisions made. This paper discusses the approaches to the modeling of the composition of the malt mixture and the mode of lager beer production. A special cubic simplex-lattice design with two replications was used to model the mixture with three malt types: Pilsner, Caramel Pils and Caramel Munich type 2. Models for the main brewing characteristics, i.e., wort extract and color, as well as models for the biological parameters of the mash, i.e., phenolic compound content and antioxidant potential, were developed using different methods. Multi-objective optimization was carried out and a specific mixture was developed for the production of lager beer. The influence of acidulated malt, lactic acid and CaCl2 additions on the extract yield and malt mash filtration time were established through one-factor experiments. The extract and fermentable sugar yield during individual pauses in the mashing mode was studied with a view to its optimization. [ABSTRACT FROM AUTHOR]

Significant innovations have occurred over the past 50 years in the malting and brewing industries, focused on optimization of the beer mashing, boiling and fermentation processes. One of the challenges faced in beer brewing has been in the malting process to obtain the desired malt and wort quality to produce high-quality beer products. The hydrolytic enzymes produced during grain germination are mostly entrapped inside the cellular matrices of the grain. The intra-grain diffusion of enzymes for in-situ hydrolysis, as well as diffusion of enzymes to wort, depends upon the malt size and malt size fractions obtained after milling. This review investigates the relationship between varying barley grain particle size distribution and the efficiency of the malting and mashing processes. Recommended ideal particle size of barley grain before and after milling are proposed based on the review of existing literature. Each brewing batch of grains with a proportion of >80% plump grains (>2.5 mm in size) is suggested to be the optimal size before milling, whereas the optimum grain particle size after milling ranged between 0.25 and 0.5 mm. The current review will summarize the theoretical aspects for malt milling and the particle size characteristics for optimizing the brewing process. [ABSTRACT FROM AUTHOR]

Beer brewing is a complex process that comprises many fundamental unit operations. Over the last few years, craft brewing has become very popular, and the number of small-scale commercial brewers has drastically increased. However, due to the use of traditional beer-making methods, energy utilization in craft breweries tends to be inefficient, resulting in poor sustainability. Therefore, there is a necessity for a holistic analysis on the energy profile of craft beer brewing to evaluate its environmental performance on a unit operation basis. In this study, a gate-to-gate life cycle assessment was conducted to analyze and compare the environmental profiles of craft beer brewing, including ale and lager, at commercial (microbrewery) and pilot scales. A process simulation model was developed to estimate the electricity and/or natural gas uses of each unit operation, including heating, mashing, boiling, whirlpool, cooling, fermentation, and maturation. The model accurately predicted the steam use for pilot-scale brewing and the electricity and gas bills of a microbrewery. The beers brewed at the microbrewery scale (21.5-barrel brewhouse) had 2–11-fold lower environmental impacts than those brewed at the pilot scale (1-barrel brewhouse), and lager beer generally produced 11–32% higher impacts than ale. The fermentation and maturation steps in brewing were the major contributors to global warming and terrestrial acidification, whereas the mashing step was predominantly responsible for marine eutrophication. This study provides craft brewers with a useful tool for identifying the hotspots of energy use in their processes and developing potential improvement strategies. [ABSTRACT FROM AUTHOR]

Why was the work done: Filtration enzymes targeting the degradation of arabinoxylan and ß-glucan are widely used in the brewing industry to improve wort and beer filtration. Although these enzymes have proven their effectiveness in improving lautering efficiency and beer filterability, the effect of varying dosage and type of enzyme preparation on beer composition and quality has not been described. How was the work done: The impact of dose of different filtration enzyme preparations (Laminex®750, Laminex®C2K, and Laminex®MaxFlow4G) was investigated on the free ferulic acid content in wort, chemical composition and viscosity of beer, together with the content and structure of arabinoxylan and ß-glucan. What are the main findings: The structural features of arabinoxylan and ß-glucan in beer were strongly influenced by the dosage and type of filtration enzyme. In general, the high-molecular weight (HMW) arabinoxylan and HMW ß-glucan and total ß-glucan content in beers decreased with increasing enzyme dosage, while the total arabinoxylan levels increased. The HMW arabinoxylan content was strongly related to beer viscosity. The use of filtration enzymes decreased HMW arabinoxylan content and beer viscosity, which could affect the palate fullness. Overdosing filtration enzymes resulted in more ferulic acid, the precursor (in the presence of phenolic yeast) of the clove-like 4-vinyl guaiacol. Why is the work important: This work provides brewers with insight as to how filtration enzymes affect beer composition and viscosity. Further it can help make an informed choice of the type of filtration enzyme and the dosage applied during mashing. [ABSTRACT FROM AUTHOR]

Introduction. Changes in mashing modes can increase extraction of biological compounds from malt. Biochemical composition of the malt wort with prolonged action of proteolytic enzymes during the mashing process was determined. Materials and methods. The raw material composition made from three types of malt: base malt, melanoidin malt and roasted malt. Analysis of the amino acid, carbohydrate and lipid profile in modified proteolytic wort was done by chromatographic methods. Results and discussion. Wort analysis identified 19 amino acids; ten of them were essential amino acids. Total content of amino acids in control wort was 1349 mg/l. Total amino acid content in wort modified by mashing mode 1 increased by 55% to 2096 mg/l. Total content of amino acid in wort modified by mashing mode 2 increased by 90% to 2572 mg/l. Proline content in modified wort was the highest: 437 mg/l in wort modified by mashing mode 1; 568 mg/l in wort modified by mashing mode 2. The high content of leucine, arginine, and phenylalanine was observed in modified wort. The percentage increase in the content of individual amino acids in the modified wort varied significantly. Thus, the content of valine and phenylalanine increased by 101-102%, meanwhile the amount of glycine increased only by 18%. Chromatographic analysis showed that prolonged proteolysis has no effect on the carbohydrate and lipid composition of the wort. Total fatty acid content was in the range from 5.6 to 11.4 mg/l. Difference in total content of fatty acids between samples of modified proteolytic wort was more than 30%. Analysis of wort showed the presence of 11 fatty acids. Palmitic and linoleic acids were predominant in fatty acid profile in modified proteolytic wort: the content of palmitic acid was 38-48%, and the content of linoleic acid (omega-6) was 30-37% from total fatty acid amounts. Carbohydrate profile of the modified proteolytic wort presented by maltose, 53.1%; dextrins, 23.4%; maltotriose, 15.2%, and glucose, 8.3%. Carbohydrate profile of modified proteolytic wort had no difference with traditional malt wort. Conclusions. Modified proteolytic wort after prolonged proteolysis during mashing is a good source of amino acids. Long proteolytic rest significantly increases the content of amino acids in malt wort, which can be further used in the technology of dietary supplement or functional drinks. [ABSTRACT FROM AUTHOR]

The molecular structural changes in starch in barley malts during mashing (a major step in brewing beer) with and without protein removal were investigated using size exclusion chromatography. The aim was to uncover how proteins affects barley starch degradation in brewing. It was found that for malts containing lower β-amylase activity, protein removal significantly increased fermentable sugar content, whilst no significant change was observed for malts with higher β-amylase, with or without addition of a metalloprotease (Neutrase®). However, metalloprotease addition significantly reduced both the content and molecular sizes of remaining wort-soluble starches. This suggests that the effects of malt protein removal on starch degradation, particularly on fermentable sugar production, largely depend on malt enzyme activity, especially that of β-amylase. This provides useful information for brewers: for example, the fact that soluble starch molecular structure correlates significantly with fermentation efficiency gives a new criterion for selecting barley varieties for optimal brewing performance.

The molecular structural changes in starch in barley malts during mashing (a major step in brewing beer) with and without protein removal were investigated using size exclusion chromatography. The aim was to uncover how proteins affects barley starch degradation in brewing. It was found that for malts containing lower β-amylase activity, protein removal significantly increased fermentable sugar content, whilst no significant change was observed for malts with higher β-amylase, with or without addition of a metalloprotease (Neutrase®). However, metalloprotease addition significantly reduced both the content and molecular sizes of remaining wort-soluble starches. This suggests that the effects of malt protein removal on starch degradation, particularly on fermentable sugar production, largely depend on malt enzyme activity, especially that of β-amylase. This provides useful information for brewers: for example, the fact that soluble starch molecular structure correlates significantly with fermentation efficiency gives a new criterion for selecting barley varieties for optimal brewing performance.

Triticale grain, a wheat–rye hybrid, has been reported to comply very well with the requirements for modern brewing adjuncts. In this study, two triticale varieties, in both unmalted and malted forms, were investigated at various ratios in the grist, applying different mashing regimes and concentrations of the commercial enzyme Shearzyme® 500 L with the aim of evaluating their impact on wort production. In order to capture the complex relationships between the input (triticale ratio, enzyme ratio, mashing regime, and triticale variety) and output variables (wort extract content, wort viscosity, and free amino nitrogen (FAN) content in wort), the study aimed to implement the use of artificial neural networks (ANNs) to model the mashing process. Also, a genetic algorithm (GA) was integrated to minimize a specified multi-objective function, optimizing the mashing process represented by the ANN model. Among the solutions on the Pareto front, one notable set of solutions was found with objective function values of 0.0949, 0.0131, and 1.6812 for the three conflicting objectives, respectively. These values represent a trade-off that optimally balances the different aspects of the optimization problem. The optimized input variables had values of 23%, 9%, 1, and 3 for the respective input variables of triticale ratio, enzyme ratio, mashing regime, and triticale variety. The results derived from the ANN model, applying the GA-optimized input values, were 8.65% w/w for wort extract content, 1.52 mPa·s for wort viscosity, and 148.32 mg/L for FAN content in wort. Comparatively, the results conducted from the real laboratory mashing were 8.63% w/w for wort extract content, 1.51 mPa·s for wort viscosity, and 148.88 mg/L for FAN content in wort applying same input values. The presented data from the optimization process using the GA and the subsequent experimental verification on the real mashing process have demonstrated the practical applicability of the proposed approach which confirms the potential to enhance the quality and efficiency of triticale wort production.

Consumers are more than ever in search of novel and exciting beer choices, and brewers are, therefore, continuously experimenting to adapt their product portfolio. One interesting way to naturally incorporate novel flavors and tastes is by using alternative adjuncts, but this is not always an easy and straightforward process. In this study, a 40% unmalted alternative adjunct (einkorn, emmer, spelt, khorasan, quinoa, amaranth, buckwheat, sorghum, teff, and tritordeum) or reference (barley malt, unmalted barley, and unmalted wheat) was added to 60% barley malt, after which three different laboratory mashing processes (Congress mash, Congress mash with pre-gelatinization of the adjunct, and Evans mash) were performed, and their behavior during mashing and the resulting wort characteristics were investigated in detail. Overall, the extraction process of all 10 unmalted alternative adjuncts was not complete for all three laboratory mashing processes, whereby Congress mashing resulted in the highest extract and fastest filtration, whereas Evans mashing resulted in the lowest extract and slowest filtration. Pre-gelatinization of the unmalted was generally only beneficial for adjuncts with high onset starch gelatinization temperatures. This process also inactivated endogenous enzymes in the unmalted adjuncts, which had an adverse effect on the mashing process.

Mashing is one of the key steps in beer brewing which influences the sensory quality of beer. Polyphenols can affect the quality and stability of beer. In pilot brewing experiments (200 l) of pale lager, the influence of the mashing on the content of polyphenols in beer was investigated for four variants, listed from the least to the most intensive: infusion (INF), single decoction (1DM), double decoction (2DM), and triple decoction (3DM). The profiles of proanthocyanidins, flavonoids, and prenylflavonoids were determined by UHPLC‒MS/MS. Antioxidant activity was measured using two methods, ARA-DPPH (1,1-dipyridyl-2-picryl hydrazyl) and RC-DCPI (2,6-dichlorophenol indophenol). The results showed a significant effect of decoction mashing on polyphenols in beer. The values of total polyphenols, reducing capacity RC-DCPI, and antiradical activity ARA-DPPH were higher for the decoction than for the infusion by 22%, 38%, and 26%, respectively. Flavanols and proanthocyanidins increased from INF to 3DM (by 16% and 38%, respectively). Even the hop-derived flavonols and prenylflavonoids increased from INF to 3DM by 10% and 37%, respectively. These results suggest that decoction mashing, especially the more intensive variants, results in a significant increase in all flavonoids in beer, with a possible benefit for the sensory stability of beer and/or the health of beer consumers. [ABSTRACT FROM AUTHOR]

Beer ranks third in terms of consumption worldwide, and its technology is constantly being improved and perfected. The boom in craft brewing has led to the production of thousands of new types of beer, but most often without scientific justification of the technological decisions made. This paper discusses the approaches to the modeling of the composition of the malt mixture and the mode of lager beer production. A special cubic simplex-lattice design with two replications was used to model the mixture with three malt types: Pilsner, Caramel Pils and Caramel Munich type 2. Models for the main brewing characteristics, i.e., wort extract and color, as well as models for the biological parameters of the mash, i.e., phenolic compound content and antioxidant potential, were developed using different methods. Multi-objective optimization was carried out and a specific mixture was developed for the production of lager beer. The influence of acidulated malt, lactic acid and CaCl2 additions on the extract yield and malt mash filtration time were established through one-factor experiments. The extract and fermentable sugar yield during individual pauses in the mashing mode was studied with a view to its optimization.

The basic step in beer production is mashing, during which insoluble starch chains, and to a lesser extent cell walls and proteins are broken down by enzymatic hydrolysis. Since the beginning of the modern brewing process there have been empirical studies into the optimum effective temperatures of the corresponding enzymes, and mashing has been carried out accordingly. The resulting resting temperatures of proteolysis, cytolysis and amylolysis with the maltose and saccharification rest, are now rarely changed, only being adapted to the properties of the raw materials used to a limited extent. New varieties of barley and other raw materials used in breweries, as well as modern processes in malting plants, ensure better enzyme potential and optimized malt gelatinization temperatures. The aim of this paper is to determine enzyme activity in barley malt during mashing. For this purpose, isothermal mashing was used, i.e., a mashing process with a constant resting temperature over the entire mashing period. The obtained worts were analyzed for the attributes of extract, final attenuation, β-glucan, total nitrogen, free amino nitrogen, viscosity, and pH as well as sugar composition and individual amino acids. The change in these attributes indicates the enzyme activity of the malt. [ABSTRACT FROM AUTHOR]

Microalgae, and particularly the cyanobacterium Arthrospira platensis (spirulina), have attracted much attention due to their wide range of uses. The potential use of spirulina in food is mainly driven by its high content of macro and micronutrients including proteins, γ-linolenic acid, sulfated polysaccharides, minerals, vitamins, and the natural pigment phycocyanin. Despite these potential benefits, spirulina is still not widely used in the food industry due to numerous technological challenges during manufacturing or specific sensory issues in the final product. This research deals with the feasibility of integrating spirulina into the brewing process to create a tasty beer with high consumer acceptance. In the novel recipes, 5% (w/w) of the malt was replaced by spirulina powder. The first part of the study investigated inclusion at different time points throughout manufacturing of a reference beer style (mild pale ale). Compared to the control, alcoholic fermentation was slightly influenced by cyanobacterial biomass but resulted in a beer with a typical beer-like character. Sensory evaluations including a simple descriptive test, a popularity analysis, and Just-About-Right-Questions, indicated a complex alteration in the sensory properties. This includes a dominant algal taste that disturbs the character of the pale ale beers but also a deep blue color of the beer, if spirulina was included during the wort cooling phase. Based on these results, another set of beers with a higher original extract concentration and increased hop dosages was produced. These beers had a high popularity (6.0 original TESTSCORE; 7.12 and 6.64 optimized TESTSCORE), and also exhibited a deep blue color due to the natural pigment phycocyanin from spirulina. Further, bitterness and algal taste was rated by most of the panelists to be “just right” and the simple descriptive test indicated “sweetness” as important attribute which was not expected for this hoppy beer style.

The filterability of barley malt is a critical quality parameter in beer brewing. The effects of two mashing processes (processes A and B) on the filterability of the three barley malts and their macromolecule contents were investigated. Filtration volume increased by 4%, 9%, and 13% for the Baudin, Ganpi, and Gangpi malts, respectively, and the final filtration volume of Gangpi was still poorer than that of Baudin. A downward mashing process (process C) was applied to measure the β‐glucan, arabinoxylans (AX), the polymeric arabinoxylan (PAX), and high molecular weight nitrogen (HMWN) content. The β‐glucan degradation rate of well‐modified malt during malting was higher than that of poorly modified malt, whereas the PAX and HMWN solubilization rates during malting were lower in well‐modified malt than in poorly modified malt. The filterability of poorly modified malt did not effectively improve with an initial mashing phase at 37℃. β‐Glucan degradation and PAX and HMWN solubilization during malting were critical for ensuring malt quality. Thus, the goal of predicting the filterability of malt was achieved by applying a downward mashing process. Practical Application: Quality of wort and beer as well as production efficiency is affected by the malt quality. The filterability of barley malt can affect the production efficiency and quality of wort. The change in the macromolecule contents during malting is important to ensure the production of high‐quality malt. The results of this study can provide a good method for the detection of malt filtration performance, and it also may contribute to the purpose of prediction the changes in barley malt and the resulting barley malt filterability. [ABSTRACT FROM AUTHOR]

Barley malting depends on hydrolytic enzymes that degrade storage macromolecules. Identifying barley cultivars with proteolytic activity that guarantees appropriate foaming, flavor, and aroma in the beer is of great importance. In this work, the proteolytic activity and profiles of brewing malt from Mexican barley cultivars were analyzed. Data showed that Cys‐ (at 50°C) and Ser‐proteases (at 70°C) are the major contributors to proteolytic activity during mashing. Essential amino acids, necessary for fermentation and production of good flavor and aroma in beer, were detected at the end of mashing. According to our results, Mexican cultivar HV2005‐19 exhibits similar proteolytic activities as those from cultivar Metcalfe, which is one of the most utilized for the brewing industry. Moreover, we propose Cys‐ and Ser‐proteases as biochemical markers during mashing at 50 and 70°C, respectively, to select barley cultivars for beer production. Practical applications: Proteolytic activity, which depends on activation and de novo synthesis of proteases in the aleurone layer of barley seeds, is crucial in beer production. Identifying new barley varieties that have optimal proteolytic activities is of great interest for genetic improvement programs. In this study, we propose the variety HV2005‐19 as a genotype with Cys‐ and Ser‐proteases activity similar to that from Metcalfe, which is a top variety in the brewing industry. [ABSTRACT FROM AUTHOR]

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Introduction. New innovative technologies make food industry more effective. The present paper introduces a new method of hopped wort production based on novel mash filters. Study objects and methods. The research featured two new designs of mash filters. The study of the mashing process involved malt, hops, drinking water, and beer wort. The research included generally accepted methods of physicochemical and sensory research. Results and discussion. Both models differed from the traditional design. Mash filter I had a cylindrical filtration vat at its bottom with filters in the lower and upper parts of the vat. A pump was installed on the outer side of the steam jacket to produce forced circulation of the liquid medium flow through the vat. The steam jacket was covered with Corundum Classic superfine liquid thermal insulation. Mash filter II had a filtration bottom made of perforated sheet and provided intensive liquid circulation. It also had a regulated mixer that moved the mash, which significantly improved the mashing process. After the mashing, the mash passed through the filtration bottom, separating the liquid phase from the solid phase. The crushed material was discharged through a hatch in bottom. The physicochemical and sensory profiles of the obtained beer wort and beer samples complied with State Standard 30060-93 «Beer. Methods for determination of organoleptic indices and product’s volume». Mash filter II produced beer wort of higher quality and improved the sensory properties of the finished product. This model proved more effective in extracting proteins and digestible sugars during amylolysis due to a better mixing and circulation of liquid medium flow during the wort preparation. Conclusion. The new modified mash filter made it possible to reduce the brewing time by 28.6%. Not only was it more user friendly, but it also was less heat and electricity consuming. In addition, it reduced the production area as it combined the stages of mashing and filtering.

The independent and interactive contributions of α-glucosidase to the degradation of raw starch isolated from barley and to the degradation of Lintner starch have been mathematically evaluated, but its contributions to the production of fermentable sugars during the actual mashing process have not been previously determined. Here we report the evaluation of those contributions through the use of an active site inhibitor, conduritol B epoxide, that specifically inhibits only α-glucosidase and has no effects on either α-amylase or β-amylase activities. Introduction of the inhibitor at the beginning of mashing resulted in the reduction of glucose produced by 20 − 30% throughout mashing and the reduction of maltotriose by 15 − 30%. Maltose levels were less influenced by α-glucosidase activities than were the levels of glucose and maltotriose. Hence, even though α-glucosidases are considerably thermolabile at temperatures often used for starch conversion, they can contribute significantly to the production of two of the three fermentable sugars generated from starch degradation during mashing. Additionally, we demonstrate that kilning resulted in a 12 − 34% loss of α-glucosidase activity, that 50-60% of the total activity was solubilized during mashing, most activity solubilized survived until mashing temperatures reached 55 °C, and that when mash temperatures reached 72 °C, α-glucosidase activity was rapidly inactivated. [ABSTRACT FROM AUTHOR]

Free amino nitrogen (FAN) concentrations in beer mash can be determined with machine learning algorithms from near-infrared (NIR) spectra. NIR spectroscopy is an alternative to a classical chemical analysis and allows for the application of inline process quality control. This study investigates the capabilities of different machine learning techniques such as Ordinary Least Squares (OLS) regression, Decision Tree Regressor (DTR), Bayesian Ridge Regression (BRR), Ridge Regression (RR), K-nearest neighbours (KNN) regression as well as Support Vector Regression (SVR) to predict the FAN content in beer mash from NIR spectra. Various pre-processing strategies such as principal component analysis (PCA) and data standardization were used to process NIR data that were used to train the machine learning algorithms. Algorithm training was conducted with NIR data obtained from 16 beer mashes with varying FAN concentrations. The trained models were then validated with 4 beer mashes that were not used for model training. Machine learning algorithms based on linear regression showed the highest prediction accuracy on unpre-processed data. BRR reached a root mean square error of calibration (RMSEC) of 2.58 mg/L (R² = 0.96) and a prediction accuracy (RMSEP) of 2.81 mg/L (R² = 0.96). The FAN concentration range of the investigated samples was between approx. 180 and 220 mg/L. Machine learning based NIR spectra analysis is an alternative to classical chemical FAN level determination methods and can also be used as inline sensor system. [ABSTRACT FROM AUTHOR]

Ascorbic acid oxidase (AAO) develops in the embryo tissues of barley during steeping and initial stages of germination. Two AAO enzymes have been identified. One of them is of remarkably low molecular weight (

Malt is the major source of iron (Fe) and copper (Cu) in wort and beer, and the main uptake of Fe and Cu ions happens during mashing. Past research has indicated that the mineral composition of sweet wort primarily depends on the ion removal rate during mash filtration. In this study, the capacity to remove Fe and Cu during mashing has been evaluated. Each metal was added (50 µM) at the beginning of congress mashings and the final concentrations in sweet wort were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). There was little to no difference between the samples spiked with Fe and the blanks when using pure pilsner malt, suggesting that there is an efficient binding of Fe in the spent grains. A significant, but not complete, removal was also observed for Cu-spiked samples. Mashing with roasted malt showed decreased removal of Fe while removal of Cu was increased. The effects of addition of high metal concentrations during mashing on the oxidative stability of the sweet wort were evaluated using electron spin resonance (ESR) spectroscopy and oxygen consumption. It was concluded that the spent grains have an important leveling effect on the final Fe and Cu concentrations in sweet wort, which also levels the effects on oxidative reactions. [ABSTRACT FROM AUTHOR]

(1) Background: In the current highly competitive brewing industry, most breweries may benefit from a reduction in mashing time. In this study, a novel enzymatic assay format was used to investigate the activities of α-amylase and β-amylase during different mashing profiles, with the aim to use it as a tool for optimizing the production time of an existing industrial mashing process; (2) Methods: Lab-scale mashings with eight different time-temperature programs and two different pilot brews were analyzed in terms of enzymatic activity, sugar composition, alcohol by volume in the final beer, FAN and others; (3) Results: A 20-min reduction (out of an original 73-min mashing program) was achieved by selecting a temperature profile which maintained a higher enzymatic activity than the original, without affecting the wort sugar composition and fermentability, or the ethanol concentration and foam stability of the final beer. (4) Conclusions: A method is presented which can be used by breweries to optimize their mashing profiles based on monitoring α-amylase and β-amylase activities. [ABSTRACT FROM AUTHOR]

Using the Bradford assay that measures total protein, there is a detectable lowering of polypeptide that occurs as the temperature is raised to conversion temperature, though not at the lower temperature (45oC) at which mashing was started. However, this decrease in total soluble protein is not enzyme catalysed. There appears to be no impediment to proteinase action in mashes, as added proteolytic enzymes can lower the level of detectable protein. Comparison of worts made from the same malt using a Hot Water Extract procedure and a Cold Water Extract test illustrates that the protein distribution in the latter (monitored using SDS‐polyacrylamide gel electrophoresis) is much the more complicated. It is concluded that proteolysis does occur in mashes through the action of endogenous proteinases, but that this does not manifest itself in a detectable change in soluble protein as measured by a general protein assay procedure. © 2020 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The potential to utilize low nitrogen barley for production of distilling quality malt was studied. This presents an opportunity to reduce the environmental impact of nitrogen fertilizer applications. Malting barley (cv. Octavia) was grown without the application of inorganic nitrogen fertilizer, to produce grain with a relatively low nitrogen concentration (1.16%, dry weight basis). Following micro-malting trials, dextrinizing units (58 DU) obtained from low nitrogen malt were much higher than a typical specification of 45 DU for malt with a conventional nitrogen concentration (<1.5%). A higher soluble nitrogen ratio (SNR) or index of modification (IoM) of 49 indicated greater modification of the low nitrogen barley, resulting in higher extract released into the wort. Additionally, much lower levels of β-glucan were found in low nitrogen malt wort (64 mg/L compared with over 100 mg/L in wort of conventional nitrogen malt). Low nitrogen malt also produced higher predicted spirit yields following wort fermentation and wash distillation. These findings indicate that lower nitrogen concentration barley can be processed without negatively impacting malt quality for distilling applications. The implication of these findings to help realize more environmentally sustainable production of barley for malting and use in distilling is discussed. [ABSTRACT FROM AUTHOR]

There are numerous scientific publications about the folate content of several types of beers available in commercial trade, but there is limited information about the effect of raw materials and technological steps of brewing on folate content. In this study the aim was to investigate different raw materials and the evolution of folate content during laboratory and pilot scale brewing. For the determination of folate content of different malts, three types of barley malts (Pilsner, Caramel, and Coloring), wheat malt, rye malt, and oat malt were analysed. For the study of the evolution of folate content during the brewing process, worts were produced on laboratory and pilot scale. Among malts, Pilsner type barley malt had the highest folate content (44.7 μg/100 g d.m.). During brewing the protein rest seemed to dissolve the majority of the folate content, and with the increasing temperature of the β- and α-amylase rests there was a further dissolution. Filtration and sparging did not have negative effect on folate concentration related to the extract content of the wort. Hop boiling had no negative effect on folate content, folate seemed to be stable during the one-hour boiling. Natural folate of barley malt seemed to be stable through the technological steps of brewing, offering the possibility to produce a foodstuff with high natural folate content. [ABSTRACT FROM AUTHOR]

Akey first step in the production of beer is themashing process, which enables the solubilization and subsequent enzymatic conversion of starch to fermentable sugars. Mashing performance depends primarily on temperature, but also on a variety of other process parameters, including pH and mash thickness (known as the "liquor-to-grist" ratio). This process has been studied for well over 100 years, and yet essentially all predictive modeling efforts are alike in that only the impact of temperature is considered, while the impacts of all other process parameters are largely ignored. A set of statistical and mathematicalmethods collectively known as Response SurfaceMethodology (RSM) is commonly applied to develop predictive models of complex processes such as mashing, where performance depends on multiple parameters. For this study, RSMwas used to design and test a set of experimentalmash conditions to quantify the impact of four process parameters--temperature (isothermal), pH, aeration, and the liquor-to-grist ratio--on extract yield (total and fermentable) and extract composition in order to create a robust, yet simple, predictive model. In contrast to previous models of starch hydrolysis in a mash, a unique aspect of the model developed here was the quantification of significant parameter interaction effects, the most notable of which was the interaction between temperature and mash thickness (i.e., the liquor-to-grist ratio). This interaction had a sizeable impact on important mash performance metrics, such as the total extract yield and the fermentability of the resultant wort. The development of this model is of great future utility to brewery processing, as it permits the multi-parameter optimization of the mashing process. [ABSTRACT FROM AUTHOR]

Grains of four naked oat varieties (Amant, Maczo, Polar and Siwek) and one hulled oat variety (Kozak) from three consecutive years (2018, 2019 and 2020), grown under three different nitrogen fertilization regimes (40, 60 and 80 kg of nitrogen per hectare) were malted and then mashed in the laboratory conditions for the first time; this was carried out to determine whether hulled and naked oat grains possess favourable properties as a raw material for the production of malt. Most of the analysed samples possess a favourable Kolbach index (39.06–46.82%), good extractivity (81.07–81.97%) and rather good saccharification time (13.33–26.67 min); however, some disadvantages of the produced malts could be pointed out. During the congress mashing, the filtration time of the worts produced from the hulled and naked oat malts was long (96.67–110 min) and the wort volume was not satisfactory (155–228.53 mL). Subsequent studies over oat malting and mashing need to be performed to maximize oat potential as the raw material for the production of the malt.

A holistic view of the fate of barley starch, arabinoxylan and β‐glucan throughout malting and brewing is largely missing. Here, an industrial scale malting trial and pilot brewing trial were performed, and the concentration and structural characteristics of carbohydrates were analysed at 28 key points in the process. The barley starch content decreased during malting from 75.0% to 69.7%. During mashing, malt starch was converted to fermentable sugars (75.3%), dextrin (22.8%) or was retained in spent grains (1.8%). Arabinoxylan was partially hydrolysed during malting. Despite mashing‐in at 45°C, no further solubilisation of arabinoxylan was observed during mashing. However, the average degree of polymerisation of the soluble arabinoxylan fraction decreased slightly. During fermentation, the arabinoxylan content decreased to 2.5 g/L. The amount of barley β‐glucan decreased gradually in time during malting. Of the solubilised β‐glucan, 31% was retained in the spent grains during wort filtration, slightly lowering the β‐glucan content in the wort. The β‐glucan content remained at 0.5 g/L during fermentation. Sucrose was hydrolysed during mashing, probably by barley invertases. From the total amount of malt used, 41.0% was converted to fermentable sugars. This mashing yield could have been improved by the full hydrolysis to fermentable sugars of the present β‐glucan (to 41.1%), the remaining starch in spent grains (to 42.0%) and dextrin in wort (to 50.3%). These results provide more insight into the carbohydrate conversions during malting and brewing and can act as a baseline measurement for future work. © 2020 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Maltose increases the activity and thermostability of barley β-amylase at high mashing temperatures. Here we examined the effects of maltose on malt β-amylase activity and thermostability at reduced mashing temperatures. The β-amylase activity was relatively thermostable at both 52 and 58 °C with or without added maltose. At 52 °C, only 500 mM maltose significantly increased (P = 0.0004 to P < 0.0001) Harrington β-amylase activity over mashes without maltose (controls) from 30 to 90 min of mashing. With Morex, at 52 °C, 50 to 500 mM maltose significantly increased β-amylase activity (P = 0.0004 to P < 0.0001) compared to controls at 60 and 120 min. At 58 °C, Harrington β-amylase activity was significantly increased (P = 0.017) only at 120 min with additions of 200 to 500 mM maltose. In contrast, maltose additions to Morex mashes at 58 °C significantly increased β-amylase activities at 30 min (400 and 500 mM), at 60 and 90 min (50 to 500 mM), and at 120 min (100 to 500 mM). This suggests that genotypes with a Morex-like β-amylase phenotype could benefit from low initial mashing temperatures. Incubations with 0 to 500 mM mannitol at 52 and 58 °C were compared with incubations containing maltose and in general mannitol had fewer effects than maltose. [ABSTRACT FROM AUTHOR]

Crushing and enzyme treatment are pivotal factors that cannot be ignored in the mashing stage of qingke (hull-less barley) craft beer brewing. This study aimed to explore the impact of different mashing conditions on physicochemical, fermentation, and antioxidant properties of qingke wort as well as elucidate the mechanisms of mashing conditions affecting the quality of qingke wort. The results showed that wort with a high fermentable sugar content, including maltose and glucose, could be obtained using a crushed size smaller than 0.9 mm. Furthermore, enzyme treatment further led to an increase in fermentable sugar content, enhancing the fermentation capacity of qingke wort. Notably, crushing significantly affected the antioxidant properties of qingke wort, with smaller crushed particle sizes yielded superior antioxidant properties to the wort, mainly due to the increase in the content of phenolic compounds such as chlorogenic acid, caffeic acid, and epicatechin. • Qingke malt with a crushed size of less than 0.9 mm is suitable for beer brewing. • Phenolic compounds are the main antioxidants in qingke wort. • Crushing and enzyme treatment can effectively improve the quality of qingke wort. [ABSTRACT FROM AUTHOR]

Efficient enzymatic hydrolysis of cereal starches requires a proper hydrothermal pre-treatment. For malted barley, however, the exact initial temperature is presently unknown. Therefore, samples were micro-mashed according to accurately determined gelatinization and pasting temperatures. The impact on starch morphology, mash viscometry and sugar yields was recorded in the presence and absence of an amylase inhibitor to differentiate between morphological and enzymatic effects. Mashing at gelatinization onset temperatures (54.5–57.1 °C) led to negligible morphological and viscometric changes, whereas mashing at pasting onset temperatures (57.5–59.8 °C) induced significant starch granule swelling and degradation resulting in increased sugar yields (61.7% of upper reference limit). Complete hydrolysis of A-type and partial hydrolysis of B-type granules was achieved within only 10 min of mashing at higher temperatures (61.4–64.5 °C), resulting in a sugar yield of 97.5% as compared to the reference laboratory method mashing procedure (65 °C for 60 min). The results indicate that the beginning of starch pasting was correctly identified and point out the potential of an adapted process temperature control.

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 β-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.

(1) Background: In the current highly competitive brewing industry, most breweries may benefit from a reduction in mashing time. In this study, a novel enzymatic assay format was used to investigate the activities of α-amylase and β-amylase during different mashing profiles, with the aim to use it as a tool for optimizing the production time of an existing industrial mashing process; (2) Methods: Lab-scale mashings with eight different time-temperature programs and two different pilot brews were analyzed in terms of enzymatic activity, sugar composition, alcohol by volume in the final beer, FAN and others; (3) Results: A 20-min reduction (out of an original 73-min mashing program) was achieved by selecting a temperature profile which maintained a higher enzymatic activity than the original, without affecting the wort sugar composition and fermentability, or the ethanol concentration and foam stability of the final beer. (4) Conclusions: A method is presented which can be used by breweries to optimize their mashing profiles based on monitoring α-amylase and β-amylase activities.

• Not all barley malt starch is gelatinized at 72 °C during mashing. • Small starch granules yield relatively more dextrins during mashing. • Large granules yield relatively more fermentable sugars during mashing. • Limited water availability might increase gelatinization temperature. • Annealing of small starch granules is hypothesized to occur at 62 °C. This study investigates the impact of different gelatinization characteristics of small and large barley starch granules on their enzymatic hydrolysis and sugar production during mashing. Therefore, a barley malt suspension was consecutively incubated at 45, 62, 72 and 78 °C to monitor starch behavior and enzymatic starch hydrolysis and sugar production. The combination of microscopic and rapid visco analyses showed that small starch granules persisted longer in the system and were present non-gelatinized at temperatures higher than 62 °C. HPAEC-PAD analysis showed that 8% of the total amount of starch, predominantly small granules, gelatinized at temperatures between 62 °C and 78 °C. Due to their delayed gelatinization in this system, their enzymatic hydrolysis yielded relatively more dextrins compared to what was observed for large granules. It was concluded that small granules should be taken into account when optimizing enzymatic hydrolysis of barley starch, like in brewing, distilling or bio-ethanol production. [ABSTRACT FROM AUTHOR]

The germination process activates amylolytic enzymes that can produce rice syrup through mashing, however the factors affecting enzyme activities and soluble saccharides have not been investigated. This study characterized amylolytic enzymes activities, including α‐amylase, β‐amylase, and α‐glucosidase, and soluble saccharides from germinated rice cultivars of four rice cultivars, including waxy, short grain, medium grain, and long grain, under aerobic and anaerobic germination conditions over 4 days and then mashed at 55, 65, 75, and 85 °C. The results showed that the long‐grain rice had higher activities of all three enzymes, whereas the waxy rice exhibited lower activities. Glucose and maltose were the predominant saccharides at low mashing temperatures of 55 °C and 65 °C; saccharides of degree of polymerization 3 to 7 became significant at mashing temperatures of 75 °C and 85 °C. The amount and composition of saccharides were strongly influenced by rice cultivar, and germination and mashing conditions. The findings highlight the importance of rice components and starch structure on the amount and composition of soluble saccharides from germinated brown rice. Practical Application: Rice syrup is commercially produced by the addition of external bacterial enzymes to brown or milled rice. Germinated brown rice is naturally rich in nutrients and amylases, both are produced during the germination process. Because of the presence of naturally activated amylases, germinated brown rice could be used to produce rice syrup without the addition of external enzymes while preserving the nutrients from germination of brown rice. [ABSTRACT FROM AUTHOR]

Efficiency in the recovery of the extract in malt flour mash by centrifugation In order to determine the efficiency in the recovery of the malt flour mash by centrifugation, wort extraction and the liquor retained in solid residue of spent malt flour by means of centrifugation was carried out on a laboratory scale. The recovery of the extract in the mash residue was carried out by applying one and two washes with water at 76 °C and subsequent centrifugation at 4 000 min-1 for 5 min. The results show that the recovery efficiency of the extract was 99.3%, significantly higher than that obtained by the traditional mash tun method of 97.5%, also proving that the application of a second wash is not necessary. [ABSTRACT FROM AUTHOR]

Adjuncts like rice, wheat and sorghum are used by beer manufacturers worldwide to reduce the cost of production by replacing malt as a starch source. Rice is the most widely used adjunct in Asian countries. Understanding the enzyme kinetics in mashing process is vitally important to maximize sugar yield at a minimum cost. In this research, a semi-empirical model was developed for the mashing process, based on enzyme kinetic equations and experimental results; and this model was used to optimize the operating conditions when enzymes are not added externally. As predicted by the model, when 30% (w/w) of rice was used as an adjunct the maximum sugar yield can be obtained at 56° C and 6.5 pH, and the optimum temperature for mashing process increases with acidity. Since the acidity of solution increases during the mashing process due to the formation of organic acids, use of an increasing temperature profile is recommended to get the maximum output from the mashing process. [ABSTRACT FROM AUTHOR]