Barley Wort Research Articles

Malted and unmalted oats in brewing

Using oats as a raw material in brewing has recently become the focus of increased interest. This is due to research findings that have shown that oats can be consumed safely by coeliac sufferers. It is also a response to consumer demand for products with novel sensory properties. In this study, beer was produced entirely from oat malt, from barley malt and from oat and barley malts mixed with various quantities of unmalted oats. Compared with barley wort, wort made from malted oats provided a lower extract content and had a higher protein content, but a lower free amino nitrogen content (FAN). The oat wort also showed increased viscosity and haze. The addition of unmalted oats during wort production produced significant changes in the physico-chemical parameters of both oat and barley worts and beers. Unmalted oats caused an increase in wort viscosity and haze, and a reduction in total soluble nitrogen and FAN. Unmalted oats also contributed to lowering the concentration of higher alcohols and esters. Beer made from 100% oat and barley malts exhibited a similar alcohol content. The use of an oat adjunct in both cases resulted in a lower ethanol content. The introduction of enzyme preparations during the production of wort with oat adjunct had many benefits: increased extract content and FAN; a higher volume of wort; and a lower viscosity that led to faster wort filtration. This research suggests that the use of enzymes is necessary to make production using a high proportion of oats in the grist profitable. Copyright © 2014 The Institute of Brewing & Distilling

The Influence of Malt Quality on Malt Brewing and Barley Quality on Barley Brewing with Ondea Pro, Compared by Small-Scale Analysis

Brewing high quality beer efficiently requires good quality malt for conventional malt brewing or good quality barley for barley brewing with the Ondea Pro enzyme system. The potential brewing performance of both malt and barley were compared by using two similar small-scale mashing protocols, both variations on the EBC-Congress mashing protocol, which produced wort of a similar gravity and fermentability. This was achieved by mashing 93 different malt samples with the “Final 65°C” protocol and 137 different barley samples with the barley brewing protocol. The two different mash grist sources provided an opportunity to compare and contrast these two alternative brewing systems. Overall, barley brewing with Ondea Pro produces slightly lower levels of extract, while fermentability levels were somewhat lower than malt mashed with the Final 65°C protocol but comparable with the fermentability previously observed for malt mashed with the EBC-Congress protocol. For barley brewing, high levels of fermentability, comparable with the level achieved with malt (Congress protocol), result from the selection of the appropriate quality barley for brewing. Typically, barley from malting or food grade varieties that contain the highly thermostable Sd2H β-amylase type produced the highest levels of extract and fermentability. In addition, barley brewing assessment of samples from two subsequent growing seasons produced higher extracts that were equivalent to that achieved with malt, indicating a potential seasonal impact. The worts produced by both brewing systems were of similar pH and contained similar levels of Bradford protein. The barley brewed wort did have substantially higher levels of wort lipid (measured as total fatty acids) and lower levels of FAN, although previous investigations and our results suggest that this does not adversely impact yeast fermentation performance. With respect to wort filtering and lautering efficiency, barley brewed mashes/worts were substantially superior due to reduced wort viscosity and lower β-glucan content. This was despite the higher levels of wort lipid, presumably fatty acids, observed in barley brewed wort. With both malt and barley brewing, wort lipid levels were positively correlated with wort haze but were negatively correlated with lautering and wort filtration efficiency. These observations suggest that variation in the level of lipase activity in malt could potentially impact wort filtration and lautering efficiency. Malt and barley characteristics that potentially predict extract, fermentability, FAN, wort filterability, and lautering efficiency were assessed by step-wise multi-linear regression analysis and discussed. Overall, barley brewing was shown to be reproducible, efficient, and generally comparable to conventional malt brewing. The contrast between these two brewing strategies potentially identifies barley and malt quality parameters worthy of further study to improve brewing efficiency, and product quality, from both production systems.

Production of Lager Beers from Different Types of Sorghum Malts and Adjuncts Supplemented with β-Amylase or Amyloglucosidase

Sorghum has been used in lager beer production as a source of malt and brewing adjuncts and it is viewed as an excellent choice for the production of gluten-free beers. In this research, lager beers produced from white or red sorghum malts, waxy or regular sorghum adjuncts, and β-amylase or amyloglucosidase supplementation were evaluated and compared with a control beer produced from barley malt. Worts were produced by a double-mashing procedure and brewed by typical lager fermentation. The addition of β-amylase increased the amount of fermentable sugars in the sorghum malt worts. When amyloglucosidase was added, the total sugar content was augmented 20% and the glucose content was five times higher compared with worts without exogenous enzymes. Barley and sorghum malt worts contained adequate amounts of free amino nitrogen contents. After fermentation, the barley malt beers contained approximately 1% more ethanol compared with the sorghum malt counterparts that were not supplemented with exogenous amylolytic enzymes. In beers supplemented with amyloglucosidase, the ethanol augmented 1.1% units and contents were comparable independently of the sort of malt. Fusel alcohol concentrations did not differ among treatments. The higher yields of 100% gluten-free sorghum beers were achieved when worts were supplemented with amyloglucosidase during mashing.

Tracking the Progress of Wort Sugar Production during Congress Mashing with North American Barley Cultivars and Comparisons to Wort Osmolyte Concentrations and Malt Extract

This study was conducted to test the following hypotheses: 1) increases in barley wort total sugar concentrations during mashing would be greater than those for malt extract (ME) and more closely reflect increases in wort osmolyte concentrations (OC); and 2) individual wort sugars would correlate better with OC than ME. Malts from 12 barley cultivars were mashed, and wort sugars were quantified at six time points during mashing. Over the initial 55 min of mashing, total sugars for combined cultivars increased 110% compared with 120 and 91% for OC and ME, respectively. At the end of the mashing regime, total sugars for combined cultivars increased to 116% versus 132 and 91–92% for OC and ME, respectively. This indicates starch conversion to sugars was more closely reflected by OC than ME and that after 55 min of mashing sugars and OC continued to increase due to degradation of starch and other malt components to lower molecular weight compounds. In contrast, ME remained relatively constant, supporting the first hypothesis. LSD analysis of data from combined cultivars throughout mashing revealed that both OC and total sugars increased significantly from 55 to 70°C, whereas ME did not, supporting the first hypothesis. Over all time points for combined cultivars, OC correlated better than ME with total sugar concentrations, supporting the second hypothesis. In correlations of individual sugar concentrations with ME and OC for combined and individual cultivars, OC correlated better than ME with all sugars and maltodextrins for combined cultivars and most individual cultivars, supporting the second hypothesis.

Brewing with 100% Oat Malt

Oats are a cereal with beneficial nutritional properties and also unrealized brewing potential. Furthermore, oats can be tolerated by the majority of people who suffer from celiac disease. Malting of oats produced a malt, which was found suitable for brewing a 100% oat malt beer. The mashing regime, designed by using mathematical modelling, was successfully transferred to a pilot scale plant. The improved lautering performance of oat malt was due to its higher husk content, which also led to a lower extract content in oat wort when compared to barley wort. The protein profile of oat wort, as measured by using Lab-on-a-Chip analysis, revealed that there was no significant difference in the protein profile between oat and barley wort. The fermentation of oat and barley worts followed the same trend; differences could only be seen in the higher pH and lower alcohol content of the oat beer. The flavour analysis of oat beer revealed some special characteristics such as a strong berry flavour and a lower amount of staling compounds when forced aged. This study revealed that it was possible to brew a 100% oat malt beer and that the produced beer was comparable to a barley malt beer.

Monitoring Barley Extract Utilization by Saccharomyces cerevisiae in a Microbrewery

Among the cereals used for alcohol production, barley is usually preferred due to its high carbohydrate content. Standard brewing barley wort extracts contain approx. 80�90% carbohydrates, of which maltose makes up approx. 60�70% of the total. It is, therefore, of paramount importance to understand the utilization of barley wort carbohydrate extracts by Saccharomyces cerevisiae during the fermentation process. The conversion of barley wort to beer, which is used as an index of beer strength, is a function of Saccharomyces yeast. The fermented wort has an impact on beer stability due to the presence of sugars, as well as on beer quality and shelf life. Partition high-per�formance liquid chromatography (HPLC) was used to determine the individual fermentable sugars in the wort of lager beer produced at the Wits microbrewery laboratory. The sugars (glucose, fructose, and maltose) monitored were identified by their retention times, which varied from 2.82 � 0.01 to 8.62 � 0.18 min at a 95% confidence interval. Fermented wort extract pH decreased with a concomitant increase in the yeast biomass and alcohol content of the fermenting sugars. There was a decrease in the refractive indices of the fermenting medium with the exhaustion of the sugars, resulting in a constant specific gravity of 1.015, which indicated total consumption of the sugars. The highly sensitive HPLC method of monitoring different sugar levels served as a key indicator as to when the fermentation process was complete. This process is important because it can help ensure that the wort carbohydrate chemistry and parameters (temperature and pH) are optimized to produce the maximum yield of ethanol.

Effects of processing methods on sorghum wort filtration

Effects of processing methods on sorghum wort filtration were investigated using three mashing processes to produce wort namely; infusion at 65°C, modified mash at 80°C and modified mash at 100°C. Sorghum was malted at the temperatures of 20°C and 25°C for 8 days to produce two types of malts. Well-modified barley malt was used as control. Brewing parameters measured were filtration rate, specific gravity, viscosity, reducing sugars, hot water extract, soluble extract level, fermentable extract level, and fermentability level. Results revealed that though the sorghum worts had faster filtration rate than barley in infusion at 65°C, other brewing parameters were all inferior to those of barley malt. In both modified mash at 80°C and modified mash at 100°C barley wort had higher filtration rate than the two sorghum malts. Sorghum malted at 20°C had better filtration in 80°C mashing process while sorghum malted at 25°C performed better in modified mash at 100°C. The other brewing parameters obtained from the two sorghum malts in these two modified mashing methods were comparable to those of barley malts and were adequate for brewing purposes. The results in this work showed that the performances of the two sorghum malts improved in terms of filtration; indicating that well-modified sorghum malts with appropriate processing method could eliminate filtration problems associated with sorghum brewing. The effects of malt quality and processing methods on the sorghum wort filtration rate and other brewing parameters were significant at p

Preliminary Study of the Enzymolysis of Sorghum and Barley Pentosans and their Levels in Worts

The pentosanase complex of the sorghums, unlike that of barley, does not embody a xylosidase, but as in barley, displays arabinosidase activity. Isolation and purification studies, following elution in a DEAE-SS cellulose column, reveal that unlike in barley the water-soluble pentosans are arabinans. Using a modified Bial's orcinol–HCl method, after dialysis to remove free sugars, polymeric pentosans of barley worts were found to range from 162 mg/100 ml in the unmalted grains to 239 mg/100 ml in the 6 day malts while that of the sorghum over the same period was from 41 to 79 mg/ml.

The Gel Filtration Chromatographic-Profiles of Proteins and Peptides of Wort and Beer: Effects of Processing - Malting, Mashing, Kettle Boiling, Fermentation and Filtering

Barley and malt proteins, of infusion (IoB) and decoction (EBC) mashing worts as well as commercial wort and beer, obtained from the Castlemaine Perkins brewery, Brisbane, were gel filtered, with or without further treatments. A general, similar pattern of protein and peptide profiles emerged from barley malt and beer. This confirmed the widely assumed fact that beer proteins descend from barley, some transformed and others perhaps mostly unchanged by processing. In the gel-filtrate profiles, a maximum of 8 or 9 fractions were discerned. These fractions were collected and quantified for protein contents and amino acid compositions. The first four fractions contained the proteins and polypeptides of molecular weight higher than 14,000. Consequently, the remaining fractions contain the smaller peptides (<14,000), that were completely removed by dialysis. The effects of processing on proteins and peptides varied contingent upon the type of processing step considered and the pre-chromatographic treatment. Malting was the most effective process remarkably increasing the soluble protein contents, especially the smaller peptide fractions and the colour development. This is the first report, as far as we are aware of, on the gel filtration profiles of wort and beer low molecular weight peptides including those of barley wort. The importance of the smaller peptides in foam formation and retention cannot be overemphasised. The amino acid composition of the fractions revealed much more diversity than was observed in the comparison of the profiles. Proline content of fraction 1 resembled that of barley soluble proteins while fractions F2, F3 and F4 that of glutelin and only fraction 8 that of hordein. The latter, suggests that hordeins or, at least the peptide products rich in proline, are likely to be completely digested to amino acids, during malting.

FERMENTATION OF WORTS MADE FROM 100% RAW SORGHUM AND ENZYMES

Worts made from raw sorghum and enzymes were successfully fermented even though the level of FAN present (51 mg/l) is well below that essential for fermentation of wort made from malted barley. Changes in typical fermentation parameters such as specific gravity, pH uptake of free amino nitrogen (FAN) and ammonium ions mirrored the increase in yeast cell concentration. Yeast viability remained high throughout the fermentation. Under identical fermentation conditions, malted barley worts showed typical fermentation profiles. However, malted barley worts with specific gravity maintained by the addition of D-glucose, but in which the FAN was diluted to a level similar to that found in a wort made from sorghum and enzymes, fermented more slowly and failed to attenuate fully. Five consecutive fermentations, using yeast cropped from the preceding to pitch the current fermentation were conducted. The specific gravity profiles were essentially the same in all five fermentations. Final values of pH, yeast in suspension, yeast viability and FAN were also indistinguishable. The yeast crop taken from fermentations of worts made from raw sorghum and enzymes represented a 5-fold increase over the initial pitching rate. When compared to commercial beers, the beers derived from fermentation of worts made from raw sorghum and enzymes contained lower levels of ethyl acetate, and higher levels of both 2- and 3-methyl butanol. In the beers derived from sorghum, isobutanol was always less than 20% of the total higher alcohol concentration.

THE PROPERTIES, COMPOSITION AND FERMENTABILITIES OF WORTS MADE FROM 100% RAW SORGHUM AND COMMERCIAL ENZYMES

A mashing regime was developed using 100% raw sorghum which enabled commercially acceptable hot water extracts to be obtained in 85 minutes with minimal use of a heat stable α-amylase and proteolytic enzymes. This gave worts of HWE 295 1°/kg, with FAN levels of about 40 mg/l and ammonium ion concentration of about 60 mg/l. Higher, but commercially unacceptable, levels of proteolytic enzymes gave worts with FAN from 84.5 to 95 (mg/l). Addition of an amyloglucosidase as the commercial preparation Amylo300L, was required to convert the HWE to fermentable extract. The addition of Amylo300L, increased the DP1, DP2 and DP3 carbohydrate fractions of the worts from 22% to more than 90% of the total, compared to about 80% for a wort made from malted barley without the use of enzymes. Two different proteolytic enzymes gave different extracts and FAN contents presumably reflecting either differences in susceptibilities of the sorghum to the two enzymes or the presence of different additional enzyme activities in the different preparations. The level of ammonium ions in malted barley worts was 86 mg/l and up to 88 mg/l in worts produced from sorghum and enzymes. Enzyme addition produced increased levels of ammonia. The content of Group A (the most readily assimilated) amino acids was proportionally higher in sorghum worts compared to malted barley wort. Worts made from raw sorghum and enzymes, containing as little as 40 mg/l FAN, were fully attenuated. The yeast consumed about 35 mg/l FAN and 45 mg/l ammonium ions. Under identical fermentation conditions, the same yeast, fermenting a malted barley wort of comparable extract consumed 104 mg/l FAN and 37 mg/l ammonium ions.

Amylolytic potentials and wort fermenting components of Nigerian sorghums and barley

The diastatic power of four 'improved' Nigerian sorghum cultivars was produced principally by α-amylolytic activity, unlike that of Nigerian Proctor barley which came principally from β-amylolytic activity. Free amino nitrogen levels and extracts of the sorghums were higher than those of barley when the sorghum was mashed in a modified procedure in which the separated active wort was added to the gelatinized (and cooled) sorghum starch of the mash. The percentage fermentability of the sorghum worts ranged from 76 to 79% for the four cultivars as against 83% for Proctor barley. Maltose in the sorghum worts was about 15 mg/ml compared with 50 mg/ml in the barley wort. Maltotriose in the sorghum worts was 14 to 16 mg/ml while in barley it was 11 mg/ml.

β-Glucan in Barley, Malt, and Congress Wort by Fluorescence

β-Glucan in Barley, Malt, and Congress Wort by Fluorescence

Beverage stabilization through enzymatic removal of phenolics

Abstract In the production of beverages such as wine, fruit juice and beer, the removal of phenolics (coumaric acids, flavans, antho‐cyanins ) in order to prevent discoloration, haze and flavour changes is a regular practice based on the addition of proteins, adsorbants and PVPP (polyvinylpolypyrrolidone). In this experiment, Laccase, Tannase and Peroxidase were separately added to grape musts and barley worts in order to ascertain the effectiveness of their use as stabilizer in wine and beer processing. The effects of Laccase were examined more closely, as this enzyme acts on a wide range of phenolics in these beverages and at an adequate pH level. Some positive results seem to confirm the potential usefulness of either Laccase and Tannase as a pre‐fermentative treatment, coupled with conventional fining.

Continuous ethanol production by immobilized yeast reactor

Saccharomyces cerevisiae yeast immobilized in calcium alginate gel beads was employed in packed-bed column reactors for continuous ethanol production from glucose or cane molasses, and for beer fermentation from barley malt wort. With properly balanced nutrient content or periodical regeneration of cells by nutrient addition and aeration, ethanol production could be maintained for several months. About 7 percent (w/v) ethanol content could be easily maintained with cane molasses diluted to about 17.5 percent (w/v) of total reducing sugars at about 4 to 5 h residence time. Beer of up to 4.5 percent (wv) of ethanol could be produced from barley wort at about 2 h residence time without any addition of nutrients.

Immobilized ?-glucanases and their applications

A number of β-glucanase active enzyme preparations were successfully immobilized either by adsorption on Duolite S-761 phenol-formaldehyde resin or covalently on silanized Spherosil XOB-075 porous silica beads to obtain remarkably stable active biocatalysts. A Duolite immobilized β-glucanase could be employed for continuous treatment of barley wort in a packed-bed column reactor to decrease viscosity and to improve filtrability. A Duolite immobilized cellulase that exhibited no detectable Avicel hydrolyzing activity could be applied for batch treatment of wheat starch process water. The same enzyme when covalently bound on Spherosil was, however, capable of hydrolyzing microcrystalline cellulose in a recirculating fluidized-bed reactor.

VARIETAL DIFFERENCES IN BARLEYS AND MALTS: VI. AUTOLYTIC PROTEOLYTIC ACTIVITY OF MALT AND ITS CORRELATIONS WITH WORT NITROGEN AND BARLEY NITROGEN FRACTIONS

The proteolytic activity of 144 samples of malt, representing 12 varieties grown at 12 experimental stations in Canada, was determined by an autolytic method. Certain varieties differed widely in average activity (Olli, 291; O.A.C. 21, 235; and Wisconsin 38, 150 units), those of poor malting quality tending to give low values. The spread between station means was also large (Beaverlodge, 284; and Nappan, 149 units).The correlations between proteolytic activity, barley nitrogen fractions, total barley nitrogen, and wort nitrogen (data given in an earlier paper), were also studied. Intra-varietal partial correlations independent of total nitrogen, between proteolytic activity and nitrogen fractions, were all insignificant. Corresponding inter-varietal partial correlations were insignificant for insoluble and alcohol-soluble nitrogen, but highly significant for salt-soluble barley nitrogen and wort nitrogen. A close inter-varietal relation was found between proteolytic activity and salt-soluble barley nitrogen, and it was impossible to demonstrate that these two properties influenced wort nitrogen independently.