Effect of varying starch properties and mashing conditions on wort sugar profiles

The aim of this research was to investigate the relationship between starch composition in barley and its malted counterpart alongside malt enzyme activity and determine how these factors contribute to the fermentable sugar profile of wort. Two Australian malting barley varieties, Commander and Gairdner, were sourced from eight growing locations alongside a commercial sample of each. For barley and malt, total starch and gelatinisation temperature were taken, and for malt, α‐ and β‐amylase activities were measured. Samples were mashed using two mashing profiles (infusion and Congress) and the subsequent wort sugar composition and other quality measures (colour, original gravity, soluble nitrogen) were tested. Variety had no significant (<0.05) effect on any barley, malt, enzyme or wort characteristics. However, growing location impacted gelatinisation temperature, colour, malt protein content and original gravity. The gelatinisation temperature in malt samples was higher, by ~0.8°C, than in the equivalent barley sample. Several malt samples, even with protein contents <12.0%, had gelatinisation temperature >65°C. The fermentable sugars measured in the malt prior to mashing showed a higher proportion of maltose than glucose or maltotriose. In addition, there were significant differences in the amount of sugar produced by each mashing method with the high temperature infusion producing a higher amount of sugar and proportionally more maltose. There is scope for further research on the effect of genetics and growing environment on gelatinisation temperature, mash performance and fermentable sugar development. Routinely measuring gelatinisation temperature and providing this information on malt specification sheets could help brewers optimise performance. © 2019 The Institute of Brewing & Distilling     

Variation in maltose in sweet wort from barley malt and rice adjuncts with differences in amylose structure

Starch from malt and solid adjuncts provides the majority of fermentable sugars for fermentation. However, there is no current data on the variation in starch structure (particularly long chained amylose) and its impact on the final wort composition of fermentable sugars, specifically maltose. This is the first study to report variation in amylose structure from barley malt and rice used as an adjunct and how this impacts the production of maltose. We compared four commercial malts with two rice adjuncts mashes, in solid and liquid additions, with an all‐malt mash used as a control. All combinations of malt and rice adjuncts were tested under two grist‐to‐liquor (G:L) ratios (1:3 and 1:4) in a 65°C ramped mash. After mashing, the wort original gravity and maltose concentration were measured. The commercial malts had different malt quality but very similar gelatinisation temperatures (~65°C). The malts varied in starch and amylose contents but had only minor variations in average amylose chain lengths. The two rice adjuncts also had similar average amylose chains lengths, but quite different amylose contents, and hence different gelatinisation temperatures. The results showed that liquid adjunct mashes had higher original gravity and maltose concentration for both G:L ratios. However, there was no consistent result in original gravity or maltose between G:L ratio or adjunct type, suggesting interactions between each malt and rice adjunct. Knowing amylose chain length could improve understanding of the potential maltose levels of the sweet wort prior to fermentation. © 2018 The Institute of Brewing & Distilling     

Studies on the mashing conditions of teff (Eragrostis tef) malt as a raw material for lactic acid‐fermented gluten‐free beverage

Formation of extracts and fermentable sugars during mashing can be limited by incomplete starch gelatinisation. The aim of this research was to develop mashing programme for 100% teff malt as a potential raw material for gluten‐free lactic acid‐fermented beverage. Isothermal mashing at temperatures ranging between 60 and 84 °C was conducted, and the highest extract (85%) was observed for the wort samples produced at temperatures higher than 76 °C. Sixty‐minute rest at 71 °C resulted in higher fermentable sugars than other tested conversion rest temperatures. Inclusion of lower mashing‐in temperature in the mashing programme also substantially improved the concentrations of free amino nitrogen (128 mg L^?1) and fermentable sugar (58 g L^?1) in the final wort. Therefore, 30‐min rest at 40 °C followed by 60‐min rest at 71 °C and 10‐min rest at 78 °C was found to be a suitable mashing programme for teff malt.     

Optimisation of a Mashing Program for 100% Malted Buckwheat

The objective of this study was to develop a temperature programmed mashing profile for 100% buckwheat malt. Both standard brewing methods and a rheological tool (Rapid Visco Analyser) were used to characterise worts and mashes. An optimal grist: liquor ratio of 1:4 was observed. At this ratio, buckwheat malt showed a gelatinisation temperature of 67°C and barley malt 62°C. A one hour stand at 65°C exhibited higher FAN levels, fermentable extracts and lower viscosity values than stands at 67°C or 69°C, and was therefore used in further mashing trials. An extra mashing step of 30 min, at any of the tested temperatures, increased extract values a minimum of 4%, decreased viscosities a minimum of 0.20 mPas, and increased fermentable extracts 12%. Best results were obtained when a mashing‐in temperature was used in the range of 35°C to 45°C. These mashing‐in temperatures were used to design an optimal mashing procedure: 15 min at 35°C; 15 min at 45°C; 40 min at 65°C; 30 min at 72°C; 10 min at 78°C. This program showed higher extract values and fermentable extract values (72.7% and 49.9%) than obtained by congress mashing (65.3% and 40.0%), thus successfully optimising the mashing program.     

Investigation of mashing regimes for low‐alcohol beer production

Low‐alcohol beer can be obtained by physical and biological methods. The group of biological methods includes modification of the mashing regimes and changes in the fermentation process. The aim of the present work was to study two mashing regimes for low‐alcohol beer production. The increase in the mashing duration at 50 °C led to a linear increase in the extract and the concentration of reducing and fermentable sugars in the wort. It was found that the rate of formation of reducing sugars was higher than that of the formation of fermentable sugars, which can be used for the optimization of the mashing process. The introduction of a pause at 77 °C did not lead to a substantial increase in the concentration of fermentable extract, but did lead to an increase in the total and non‐fermentable extract. The available nitrogen content in the laboratory wort was in the range of 120–150 mg/dm³. As a result of conducting fermentation processes with the top‐fermenting yeast strain Saccharomyces cerevisiae S‐33, it was found that the combination of a small amount of fermentable sugars and a low fermentation temperature led to a beer being obtained that met the requirements for a low‐alcohol beverage. Copyright © 2016 The Institute of Brewing & Distilling     

Validation and application of osmolyte concentration as an indicator to evaluate fermentability of wort and malt

The objective was to develop a new simple and quick approach to predict fermentability, based on osmolyte concentration (OC). Eight malts were assayed for diastatic power, starch‐degrading enzymes [α ‐amylase, β ‐amylase and limit dextrinase (LD)] and malt OC (MOC). All malts were mashed to determine wort OC (WOC), real degree of fermentation (RDF) and sugar contents in a small‐scale mashing protocol. The results showed that MOC was correlated with malt α ‐amylase, LD, the resultant WOC, RDF and fermentable sugar (r  = 0.813, 0.762, 0.795, 0.867, 0.744, respectively), suggesting that MOC was discriminating in predicting levels of malt amylolytic enzymes, wort sugar and RDF without the mashing and fermentation process. Moreover, WOC showed stronger correlations with malt α ‐amylase, LD, RDF and fermentable sugars (r  = 0.796, 0.841, 0.884, 0.982, respectively), suggesting that WOC can be used to quickly predict wort sugar contents and RDF without a fermentation step. Furthermore, the effects of mashing temperature and duration on WOC, RDF and sugar contents are discussed. Adjusting mash temperature to 65°C or extending the mash duration dramatically increased RDF and WOC, whereas malt extract was relatively stable. Similarly, WOC showed significant correlations with RDF and fermentable sugars (r  = 0.912 and 0.942, respectively), suggesting that WOC provides a simple and reliable tool to assist brewers to optimize mash parameters towards the production of ideal wort fermentability. In conclusion, the ability of OC to predict malt fermentability and sugar content allows brewers to keep better control of fermentability in the face of variation of malt quality, and to quickly adjust mashing conditions for the consistency of wort fermentability. Copyright © 2017 The Institute of Brewing & Distilling     

Effect of Amyloglucosidase on Wort Composition and Fermentable Carbohydrate Depletion in Sorghum Lager Beers

A three‐factorial experiment with a level of confidence of P < 0.05 was performed to study fermentable carbohydrate depletion and ethanol production during 144 h fermentations of lager beers produced with barley malt (BM), sorghum malt (SM), refined maize (MZ) or waxy sorghum (WXSOR) grits treated during mashing with or without amyloglucosidase (AMG). The percentage glucose, maltose and maltotriose, based on total fermentable carbohydrates for the BM wort was 20, 68 and 13% and for the SM wort 35, 48 and 17% respectively. Treatment with AMG increased wort glucose from 9.3 to 24.5 g/L wort and total fermentable sugar equivalents, expressed as g glucose/L, from 59.2 to 72.6 g/L wort. The SM worts had approximately 50% more glucose and 40% less initial maltose content respectively compared to the BM worts. The WXSOR grits produced worts and beers with similar properties to those produced from the MZ adjuncts. AMG addition led to a >2.5 fold increment in wort glucose and 23% in total fermentable carbohydrate content. Linear regression analysis determined that the consumption rate of fermentable carbohydrates during fermentation followed first order reaction kinetics. Depletion times to reach 50% of the initial concentrations of glucose, maltose and maltotriose were 49, 128 and 125 h, respectively, clearly indicating that the fermenting yeast preferred glucose. Maltose and maltotriose depletion times of the AMG treated worts were significantly faster and lower, respectively, when compared with the untreated worts. At the end of the fermentation, the BM beers contained higher ethanol levels (5.1% v/v) than the SM beers (3.9% v/v). For AMG treated beers, no significant differences in ethanol content were observed among samples mashed with BM and beers produced from SM and MZ grits. The results demonstrated that AMG could be used to increase the initial concentration of glucose and total fermentable carbohydrates thus decreasing dextrin levels, especially from sorghum mashes.     

Mashing of rice with barley malt under non-conventional process conditions for use in food processes

Non-conventional mashing conditions are relevant in the development of a lactic acid-fermented soymilk beverage where mashed rice is the source of carbohydrates for the fermentation and sweetness of the beverage. Advantages in the process layout could be achieved by mashing at higher pH and lower malt concentrations than normally used in the brewing industry. the work reported here assessed the consequences of mashing under non-conventional conditions. Malt concentration in the cereal part was varied from 25% to 70% (w/w), pH was varied within 5.3 to 7.1, and prolongation of the holding times at 50°C and 62°C was investigated. Regression equations have been established for predicting yields of soluble protein, low molecular weight sugars and total fermentability as functions of pH and malt concentration. the results showed that the maltose yield was constant while glucose, maltotriose and total fermentable sugar yields decreased slightly with increasing pH and decreasing malt concentration. Prolonged mash holding times at 50°C and 62°C gave minor increases in protein yields only. It is concluded that it is quite acceptable to use non-conventional mashing conditions when a mashing step is integrated in other food processes.     

Influence of sorghum grain type on wort physico‐chemical and sensory quality in a whole‐grain and commercial enzyme mashing process

To determine the most suitable types of sorghum for whole‐grain adjunct in lager beer brewing, 14 cultivars of five different types: white tan‐plant, white non‐tan‐plant, red non‐tannin, white tannin (type II) and red tannin (type III) were evaluated. The effects of grain type on wort physico‐chemical and sensory quality with raw grain and malt plus commercial enzyme mashing were assessed. Tannin content correlated significantly and negatively with wort extract and fermentable sugars (p < 0.001) and free amino nitrogen (FAN; p < 0.1). This is attributable to inactivation of the exogenous enzymes by the tannins during the mashing process. However, the type II tannin sorghums had wort quality attributes closer to the non‐tannin sorghum types, probably owing to their relatively low tannin content (≤1%). Malting gave a great improvement in wort extract, fermentable sugars and FAN, but substantially influenced wort sensory properties in terms of higher sourness, bitterness and astringency, as well as the expected more malty flavour. Worts from raw red non‐tannin sorghums were similar to those of white tan‐plant sorghums in both physico‐chemical and sensory quality. Thus, red non‐tannin sorghums, in view of their better agronomic quality, have considerable potential as a whole‐grain adjunct in lager beer brewing. Copyright © 2013 The Institute of Brewing & Distilling     

响应面法优化麦汁糖化工艺条件

以大麦芽、小麦芽为原料,麦汁浸出物收得率为评价指标,在单因素试验基础上,利用响应面法对麦汁糖化工艺进行优化研究。结果表明,最佳的糖化工艺为小麦芽添加量为42.0%,水料比为4∶1（mL∶g）,37 ℃投料保温10 min,52 ℃糖化保温45 min,65 ℃糖化保温68 min,78 ℃保温10 min。在此优化糖化工艺条件下,测得麦汁浸出物得率为79.63%,比未优化前提高8.2%。麦汁糖化液中α-氨基酸态氮含量为272.01 mg/L,还原糖含量为9.14 g/100 mL,可溶性氮含量为1.41 g/L。     

A novel approach for the production of a non‐alcohol beer (≤0.5% abv) by a combination of limited fermentation and vacuum distillation

Despite the increasing demand, the production of non‐alcohol beers is still limited by unsatisfactory or artificial flavour and taste. In this study, a novel approach to producing non‐alcohol beer is presented, in which the alcohol‐reducing techniques, limited fermentation and vacuum distillation were combined. Starting from barley and wheat malts, wort with a low level of fermentable sugars was prepared by infusion mashing and lautering. Limited fermentation was carried out by Saccharomycodes ludwigii at 18°C. When the level of fermentable sugar was reduced by 25%, the fermented wort was quickly cooled from 18 to 0°C and held at that temperature for two days. The young beer was obtained after degassing and removal of yeast and was then subjected to vacuum distillation at 0.06 MPa to remove the alcohol. The concentrated extract is suitable for storage and transportation. The final product of non‐alcohol beer was obtained by dilution with deoxygenated water and carbonation with 6.0 g/L CO₂, followed by addition of 8–12% of regular beer and equilibration for 2–3 days to develop normal beer aroma. The results showed that the non‐alcohol beer had several favourable properties, including the alcohol level of <0.5% (v /v), colour 7.0 (EBC), thiobarbituric acid value of 1.05 and ratio of alcohols to esters of 1.08. Compared with other methods for the production of non‐alcohol beer, this novel approach produced a favourable alternative to regular beers with similar flavour characteristics and satisfactory stability. Copyright © 2017 The Institute of Brewing & Distilling     

ROLE OF ALPHA-GLUCOSIDASE IN THE FERMENTABLE SUGAR COMPOSITION OF SORGHUM MALT MASHES*

The cause of the high glucose to maltose ratio in sorghum malt worts was studied. Mashing temperature and pH strongly affected both the amount of glucose and the proportion of glucose relative to total fermentable sugars. The relative proportion of glucose was higher when mashing was performed. at pH 4.0, close to the pH optimum for sorghum alpha-glucosidase, than at the natural pH of the mash (pH 6.0–5.5). Mashing according to the EBC procedure using an enzymic malt extract with pre-cooked malt insoluble solids producing a wort containing maltose and glucose in an approximately 4:1 ratio, whereas mashing with a malt extract without pre-cooking the malt insoluble solids resulted in a wort with approximately equal amounts of maltose and glucose. Both treatments gave the same quantity of total fermentable sugars and amount of wort extract. Sorghum alpha-glucosidase was confirmed to be highly insoluble in water. All or virtually all activity was associated with the insoluble solids. Hence, it appears that the high amount of glucose formed when sorghum malt is mashed conventionally is due to alpha-glucosidase activity. Pre-cooking the malt insoluble solids inactivates the alpha-glucosidase, preventing the hydrolysis of maltose to glucose.     

Carbohydrate content and structure during malting and brewing: a mass balance study

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     

The influence of proteolytic and cytolytic enzymes on starch degradation during mashing

The objective of this research was to investigate the impact of proteolysis and cytolysis on starch degradation over the course of the mashing process. A proteolytic enzyme (Neutrase 0.8L, Novozymes) and a number of cytolytic enzymes (barley β‐glucanase from Megazyme, Shearzyme 500L and Ultraflo Max from Novozymes) were used to test their efficiency on starch degradation during mashing. The proteolytic and cytolytic enzymes had positive effects on the levels of starch‐degrading enzymes and starch solubilization during mashing, resulting in higher levels of wort sugar compared with the control, indicating that proteins and residual non‐starchy polysaccharides limited the digestibility of starch during mashing. Moreover, the proteolytic enzyme showed a significantly greater improvement than the cytolytic enzymes, yielding a 57% increase in β‐amylase, a 173% increase in limit dextrinase, rapid starch solubilization during mashing and a higher percentage of fermentable sugars in resultant wort. The increases in limit dextrinase and β‐amylase promoted by the protease suggest that sufficient proteinaceous inhibitor existed in the wort during mashing to inhibit their activities, leading to the unavailability of β‐amylase and especially limiting dextrinase. Furthermore, Ultraflo Max, which contained a β‐glucanase–xylanase mixture, showed a greater improvement than either the individual β‐glucanase or the xylanase on starch hydrolysis. These findings suggest that β‐glucanase is the major enzyme responsible for the degradation of cell walls, and that the complete hydrolysis of the residual cell walls depends on the synergistic effect of β‐glucanase and xylanase. The results suggest that brewers should adjust the degradation of the cell walls and correct the degree of protein modification in order to obtain the desired wort composition. Copyright © 2014 The Institute of Brewing & Distilling     

运用不同质量的麦芽进行双醪浸出糖化工艺的研究

<正> 前言 双醪糖化法,就是糖化过程中具有两种原料醪液;辅料醪和麦芽醪,辅料醪中添加少量的麦芽粉或酶制剂以帮助辅料淀粉液化的顺利进行。由于混合醪是杏具有倒醪煮沸的不同,这种糖化方法又可分为两类:双醪煮出糖化法和双醪浸出糖化法。国内各啤酒厂在生产下面发酵啤酒中,普遍采用了前种糖化方法(即二次糖化法),虽然它的原料利用率较高,但工艺过程较复杂,酶的反应条件不很合理,倒醪煮沸费时,热能消耗较多,且麦芽汁色度较     

Effect of mashing procedures on brewing

The effect of the double decoction mashing method (method A) and the single decoction plus infusion mashing method (method B) on brewing were compared. The trials were carried out with the same raw material (malt and a minor amount of corn as adjunct) on an industrial-scale plant. The effects of mashing methods A and B were evaluated in wort and beer samples obtained with the high gravity system. The analytical parameters of the worts and beers produced and the economic aspects of production (yield, beer quality, time and energy) were discussed. The results showed no considerable differences in beer quality, while a significant difference was observed in the composition of fermentable sugars of worts. Method B gave a wort with a higher content of fermentable sugars which were converted to alcohol during fermentation; therefore, it allowed to obtain a higher beer volumetric yield of the same quality while saving time and energy.     

低浓度淡爽型啤酒的酿造

以改善低浓度淡爽型啤酒品质为目的 ,提出了一种新颖的低浓度淡爽型啤酒的酿造方法 .采用二次煮出二段式糖化法 ,用 70 %麦芽和 3 0 %大米的原料配比 ,提高麦芽汁中糖与非糖的比值 ,并在糖化过程中添加啤酒酵母提取物作啤酒发酵的补充氮源 .所酿造的啤酒口味纯正 ,泡沫洁白细腻 ,持久挂杯 .     

Production of Malt Flavoured Low-Sugar Drink from Banana (Musa sapientum) Fig Using Amyloglucosidase

Banana fig from fully ripe banana, caramel and malt extract, food drink thickening agent, acetic acid and local hop extract (Alfalfa) were used in the formulation of a low-sugar malt drink. Banana fig was used as a replacement for malted barley. The pH, total titratable acidity (TTA), percentage sugar content, specific gravity and saccharification of the extracts were determined. The effects of optimization of the mashing process using industrial enzyme-amyloglucosidase were also evaluated. The pH and percentage sugar content of the banana fig extract decreased with increased mashed temperatures. Specific gravity of the banana fig extracts decreased with increased mashed temperatures, with values from 1.013 to 1.010 against mashed temperatures of 45°C and 80°C respectively. At temperatures of 70°C and above the saccharification was observed to be incomplete. However, the introduction of industrial enzyme-amyloglucosidase resulted in complete saccharification. The formulation of the malt flavoured low-sugar drink gave three samples of 6.2%, 7.4% and 11.8% sugar contents. Sensory evaluation carried out on the malt flavoured low-sugar drink with commercial Amstel malt drink showed no significant difference in taste and flavour for all the samples compared with reference sample at p > 0.05. But sample BS3 with 11.8% sugar content was significantly different (p < 0.05) from sample BS2 (7.4% sugar) and BS1 (6.2% sugar) in colour and general acceptability. All samples except BS1 with 6.2% sugar were accepted by the panellists. This malt flavoured low-sugar drink could thus help reduce health complications in conditions associated with high sugar consumption. The use of additional enzymes in combination with the amyloglucosidase could improve the extract yield, nutritional and sensory qualities of the drink.     

Comparison of the impact on the performance of small‐scale mashing with different proportions of unmalted barley,Ondea Pro®, malt and rice

The impact of using different combinations of unmalted barley, Ondea Pro® and barley malt in conjunction with a 35% rice adjunct on mashing performance was examined in a series of small scale mashing trials. The objective was to identify the potential optimal levels and boundaries for the mashing combinations of barley, Ondea Pro®, malt and 35% rice (BOMR) that might apply in commercial brewing. Barley and malt samples used for the trials were selected from a range of Australian commercial barley and malt samples following evaluation by small‐scale mashing. This investigation builds on previous studies in order to adapt the technology to brewing styles common in Asia, where the use of high levels of rice adjunct is common. Mashing with the rice adjunct, combined with differing proportions of barley, Ondea Pro® and malt, resulted in higher extract levels than were observed for reference mashing, using either 100% malt reference or 100% barley reference and Ondea Pro® enzymes. Synergistic mashing effects between barley, Ondea Pro® and malt were observed for mash quality and efficiency parameters, particularly wort fermentability. The optimum levels of barley in the grist (with the relative level of Ondea Pro®) were assessed to be in the range 45–55% when paired with 10–20% malt and 35% rice. When the proportion of malt was reduced below 10% of the grist, substantial reductions in wort quality were observed for wort quality parameters including extract, lautering, fermentability, free amino nitrogen and haze. Extension of this new approach to brewing with rice adjuncts will benefit from further research into barley varietal selection in order to better meet brewer's quality requirements for the finished beer. Copyright © 2016 The Institute of Brewing & Distilling     

Increasing fermentable sugar yields by high‐pressure treatment during beer mashing

High‐pressure treatment, which is an effective means of enhancing enzymatic reactions, was implemented during beer mashing to increase the production yield of fermentable sugar (FS). The malt solution was heated (62, 67, and 72°C) under pressure [0.1 (1 atm), 2, 50 and 100 MPa], and the FS was measured. The amount of FS reached an equilibrium level, which was the highest at 67°C and at 2 MPa. The pressures were 2, 50, 100, and 0.1 MPa in decreasing order of FS amount at 67°C. The temperatures were 67, 72 and 62°C in decreasing order of FS amount at 2 MPa. With a mechanistic approach, only the effect of pressure on gelatinization was analysed. The gelatinization degrees were also higher at pressures higher than 0.1 MPa. This observation highlights the positive effect (increasing the FS yield) of high‐pressure treatment on beer mashing. Copyright © 2015 The Institute of Brewing & Distilling