Effects of arabinoxylan solubilization on wort viscosity and filtration when mashing with grist containing wheat and wheat malt

Arabinoxylans are partially water-extractable, high-molecular-weight polymers that contribute to the problems of viscosity and membrane filterability during beer brewing. These problems are more pronounced when wheat and wheat malt are used as adjuncts due to their higher arabinoxylan contents and higher molecular weights. This paper aimed at investigating the effects of mashing temperature, time, grist size and liquor:grist ratio on the solubilization of arabinoxylans. Results indicated that increasing the mashing temperature generally increased the amount of arabinoxylans released into the wort. When greater proportions of wheat or wheat malt were used as adjunct, higher arabinoxylan contents in the final wort were observed. The more finely ground the grist, the more were arabinoxylans released into the wort. When more diluted mashes were used, more efficient solubilization of arabinoxylans was observed. The effects of arabinoxylan content and β-glucan content on the wort viscosity were also examined using a General Linear Model (GLM). There was a good correlation (R² = 0.98) between wort viscosity and its arabinoxylan and β-glucan contents.     

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     

Quality characteristics of triticale malts and worts

Worts from triticale malts, in particular well modified malts, separated poorly from mashes. Worts prepared at 70° C had high viscosities (10–27 cSt) indicating that problems would occur during filtration in brewing. The viscosities of triticale worts were higher than those of worts from barley malts. In addition, worts from well modified malts were generally turbid. Proteinaceous material (partly degraded prolamins) was the primary cause of this turbidity. Although the degree of malt modification did influence the rate of wort separation, it had little effect on wort viscosity. High viscosity was caused by pentosans dissolved from the triticale malt during mashing. Oxidative gelation was not observed with these pentosans. Grains and malts were fractionated, and the high molecular weight fractions were analysed for their sugar and acyl components. All were rich in arabinose and xylose. There was a rough inverse correlation between the solubility of the poly saccharide fractions and the levels of substitution with acetyl and feruloyl residues. The poor wort separation from triticale malt grists appeared to be related to the particle size distributions, which were narrow. The sedimentation values of the grist ‘fines’ were high.     

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     

Changes in crude arabinoxylan during cloudy wheat beer brewing on a production scale

As one of the major non‐starch polysaccharides in the cloudy wheat beer, arabinoxylan has a crucial influence on the wort viscosity, foam profile and stability of the beer. In this study, the cloudy wheat beer was fermented on a production scale with a ratio of barley to wheat malt of 1:1, during which the changes in arabinoxylan were monitored in order to determine the key steps which influence the content, substitution degree of arabinoxylan (A/X) and average degree of polymerization (avDP) value of crude arabinoxylan during cloudy wheat beer brewing. The results show that the total contents of crude arabinoxylan, arabinose, xylose and galactose increased until the end of mashing and then dropped with the addition of spent grain sparging water. The crude arabinoxylan decreased during the saccharification, and then stabilized at ~10.00 mg/g. During fermentation and storage, the content of crude arabinoxylan did not change remarkably. The A/X remained at ~0.50 in the process of wort preparation and brewing and the avDP value of crude arabinoxylan decreased during saccharification and then stayed at ~3.00 in the fermentation and storage phases, which was lower because the contents of free arabinose, xylose and galactose were not subtracted from the total contents of the sugars. Therefore, wort preparation is shown the key step influencing the changes in crude arabinoxylan during cloudy wheat beer brewing. Copyright © 2017 The Institute of Brewing & Distilling     

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     

EXTRUDED SORGHUM AS A BREWING RAW MATERIAL

Small scale mashes (50 g total grist) with grists containing up to 50% by weight of extruded whole sorghum produced worts of high extract yield and low viscosity. Increasing the proportion of extruded sorghum in the grist resulted in decreasing wort filtration volume, total nitrogen and free amino nitrogen content. The wort filtration behaviour of mashes containing sorghum extruded at 175°C was superior to that of mashes containing sorghum extruded at 165°C or 185°C. The results from such small scale mashing experiments suggested that extruded sorghum compared favourably to extruded barley and extruded wheat as a brewing adjunct. Worts and beers were produced on a pilot brewery scale (100 1) from grists comprising 70% malt + 30% extruded sorghum and 100% malt under isothermal infusion mashing conditions. Mashes containing sorghum extruded at 175°C showed comparable wort filtration behaviour to that of the all malt control mash whereas mashes containing sorghum extruded at 165°C or 185°C showed poor wort filtration behaviour. Worts produced from grists containing extruded sorghum fermented more quickly than the control wort and attained lower values of final gravity. The resulting beers were filtered without difficulty. Beers produced from grists containing extruded sorghum contained lower levels of total nitrogen and free amino nitrogen compared to the control beer consistent with extruded sorghum contributing little or no nitrogenous material to the wort and beer. Beers brewed from grists containing extruded sorghum were of sound flavour and showed reasonable foam stability behaviour.     

小黑麦啤酒糖化工艺的探讨

首次采用了小麦与黑麦属间异源多倍体杂交品种——小黑麦作为酿造啤酒原料。与传统啤酒大麦原料相比 ,小黑麦不仅淀粉酶活性及蛋白质含量高 ,八种必需氨基酸平衡 ,而且产量高 ,种植费用低 ,可降低原料价格。本试验对小黑麦糖化工艺进行了探讨 ,确定糖化主要技术参数 ,麦汁质量符合酿造啤酒标准。     

Release of phenolic flavour precursors during wort production: Influence of process parameters and grist composition on ferulic acid release during brewing

In this study, the effects of mashing variables such as mashing-in temperature, time and pH, mash thickness, grist coarseness and composition, and stirring regime on the release of ferulic acid were examined. Ferulic acid is a precursor for the formation of flavour-active volatile phenols and a potent natural antioxidant in beer. Given one barley malt variety, the multitude of choice in setting various process parameters and adding brewery adjuncts during brewhouse operations can give rise to worts with widely varying ferulic acid levels. A clear difference in temperature- and pH-dependence between the release of the water-extracted and the enzymatically hydrolyzed fraction was found. The T,t-dependencies of arabinoxylan-degrading enzyme activities were correlated with ferulic acid release during mashing. Results from laboratory-scale mashing experiments were validated with those from a pilot-scale (5 h) wort production process. Enhancing the enzymatic release of phenolic flavour precursors from bound forms during mashing can greatly enhance the phenolic aroma potential of wort. Optimising this precursor release during mashing may be a means for controlling final volatile phenol levels in beer.     

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.     

THE USE OF EXTRUDED BARLEY,WHEAT AND MAIZE AS ADJUNCTS IN MASHING

The principles of extrusion cooking are summarised. In small scale trials good extracts were obtained from extruded barley when it was mashed with industrial enzymes, using a programmed temperature cycle. Extruded barley, wheat and maize and wheat flour yielded acceptable levels of extract when mashed with lager malt (70%) using a programme with 1 hour rests at 50°C and 65°C. The extracts obtained from these grists were increased above those obtained from grists of lager malt alone and the viscosities of the worts were reduced when the mashes were supplemented by preparations of bacterial enzymes. Enzyme additions also improved extract recoveries from all-malt mashes and reduced the viscosities of the derived worts. Using a temperature programmed mashing cycle and supplementary enzymes beers were prepared from a lager malt grist and grists in which the lager malt was partly replaced, by 30%, with extruded barley or extruded wheat, or extruded maize or wheat flour pellets. In every case wort was recovered relatively easily, the worts fermented normally and the beers were all fully acceptable, although their flavours did differ. However, in contrast to results of preliminary brewing trials, the head retentions of the beers made with adjuncts were unusually low, possibly because of particular enzyme additions.     

Free α-amino nitrogen production in sorghum beer mashing

Free α-amino nitrogen (FAN) is an essential nutrient for yeast growth during fermentation. Under normal conditions of sorghum beer mashing, 60°C at pH 4.0, production of FAN by proteolysis accounts for approximately 30% of wort FAN, the remaining 70% being preformed in the malt and adjunct. The quality of the FAN in sorghum beer worts is good as it does not contain a high percentage of proline. Optimum conditions for FAN production during mashing are 51°C and pH 4.6. Wort FAN was increased proportionally by raising the ratio of sorghum malt to adjunct and conversely decreased by raising the ratio of adjunct to malt. FAN was also increased by the addition to the mash of a microbial proteolytic enzyme. Wort FAN is directly proportional to malt FAN.     

Corn grist adjunct – application and influence on the brewing process and beer quality

In the brewing industry, barley malt is often partially replaced with adjuncts (unmalted barley, wheat, rice, sorghum and corn in different forms). It is crucial, however, to preserve constant quality in the beer to meet the expectations of consumers. In this work, how the addition of corn grist (10 and 20%) influences the quality of wort and beer was examined. The following parameters were analysed: wort colour, dimethyl sulphide (DMS) and protein content, non‐fermentable extract, extract drop during fermentation, alcohol content and the attenuation level of the beer, together with filtration performance. The samples (all‐malt, and adjunct at 10 and 20% corn grist) were industrial worts and the beers produced in a commercial brewery (3000 hL fermentation tanks). The application of 10 and 20% corn grist had an effect on the wort colour, making it slightly lighter (11.1 and 10.5°EBC, respectively) than the reference barley malt wort (12.2°EBC). The free amino nitrogen level, DMS and non‐fermentable extract were significantly lower in the worts produced with the adjunct; the alcohol content and attenuation levels were higher in the beers produced with adjunct. The use of corn grist, at the level of up to 20% of total load, appears to affect some of the technological aspects of wort and beer production, but it does not significantly influence the final product characteristics. Copyright © 2014 The Institute of Brewing & Distilling     

Overcoming technical barriers to brewing with green (non-kilned) malt: a feasibility study

Brewing using enzyme rich ‘green’ (germinated, but not kilned) malt has the potential to unlock considerable energy savings in the malting and brewing chain. This paper examines the major quality issues associated with green malt, by monitoring lipoxygenase (LOX) activity and S-methyl methionine (SMM) levels through a micromalting cycle both with and without rootlets after 48 h of germination. The data suggest that rootlets are a major concern when brewing with green malt and that their influence on wort and beer quality needs to be further investigated. Lipoxygenase activity and nonenal potential were measured following treatment under varying conditions of pH, temperature and pre-treatment. Results indicated that lipoxygenase activity can be controlled to a substantial degree by manipulating these limiting factors, while preserving diastatic enzyme activity. Green malt worts were then prepared from (i) whole green malt immediately post-germination; (ii) heat treated green malt (65°C x 1 h); (iii) re-steeped green malt and (iv) endosperm-rich extracts of green malt after the husk and rootlets had been removed; using laboratory mashing with a ‘LOX-hostile’ mash schedule. Data were compared with mashing of kilned pale malt made from the same green malt, as a reference point. Based on the present data, re-steeping of green malt in combination with a LOX hostile mashing environment (63°C, pH 5.2) could help to control LOX activity and the trans-2-nonenal potential of green malt. The resultant brewing process would need to be optimised to deal with the elevated SMM levels in green malt worts. © 2020 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling     

小麦麦芽在低度啤酒生产中的应用

在低度啤酒生产中，酿造时添加30％小麦麦芽，30％大麦麦芽，40％大米，采用添加复合酶补充酶活，增加可发酵糖含量，降低麦汁粘度，提高原料利用率；过滤时添加硅胶，提高啤酒非生物稳定性；酵母接种量为原料的0．6％，采用低温发酵；可减少副产物，改善啤酒风味特征；提高社会效益。     

糖化温度对7°P麦汁阿拉伯木聚糖、β-葡聚糖的影响研究

小麦是良好的啤酒酿造原料,在我国种植面积广泛,价格较低,品种多,富含蛋白质、淀粉。本文设计添加10％小麦芽进行糖化,研究不同糖化温度和糖化时间对7^oP麦汁理化指标的影响。实验结果表明,52℃15mm、63℃110min、72℃20min、78℃过滤糖化工艺中,7^oP麦汁阿拉伯木聚糖含量最多,为1034．33mg／L;52℃15min、63℃100min、72℃20min、78℃过滤糖化工艺中,β-葡聚糖含量最高,为72．96mg／L。当阿拉伯木聚糖产生919．33mg／L、β-葡聚糖产生两为72．96mg／L时,7^oP麦汁的粘度最大,此时,过滤速率为81．52mL／30min。     

以黑小麦为辅料酿造啤酒的初步研究

以黑小麦为辅料进行啤酒酿造研究,并与使用大米作为辅料和全麦酿造的啤酒进行对照,结果显示以黑小麦为辅料制得的麦汁可溶性氮含量高、多酚含量明显下降,并且其成品啤酒泡持性好,酯香突出,所以选用黑小麦为啤酒辅料具有良好的应用前景。     

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。     

Brewing Beer with Sorghum

Research reports on extracts, proteins, total nitrogen and free amino nitrogen content of sorghum malt and worts obtained from mashes indicate that sorghum is potentially an alternative substrate for conventional beer brewing in the tropics. Remarkable variations in biochemical characteristics among different sorghum cultivars affect their optimal malting conditions. Factors such as temperature and time of steeping and germinating of grains with their intrinsic enzymic activities, and kilning temperature determine the quality of malt. Further works on mashing, viscosity and fermentability of worts as well as the character of the resulting beers, such as alcoholic content, colour, taste and specific gravity tend to confirm the status of sorghum as a credible substitute for barley in beer brewing. This review reports on progress made in the use of sorghum for brewing beer.