Mash Temperature Research Articles

Simultaneous Evaluation of β-Glucan and β-Glucanase Relationship during Different Mash Temperature Profiles

High wort β-glucan may contribute to brewery processing problems such as poor run-off, slow filtration, and unwanted haze. To investigate how β-glucanase impacts wort β-glucan throughout mashing, 10 different mashes were considered with varied temperature profiles, malt bills, and levels of malt modification. The European Brewing Congress (EBC) and Institute of Brewing (IoB) mashes were employed to compare the effects of mash conditions on enzyme activity and β-glucan content. Mashes were sampled periodically and evaluated for β-glucan concentration and β-glucanase activity using Megazyme kits adapted to the Gallery™ Plus BeerMaster Discrete Analyzer (Gallery). Enzyme activity quickly decayed in modified IoB mashes (average half-life 12.4 min) accompanied by logarithmic accumulation of wort β-glucan. IoB β-glucan percent extract ranged from 30.3% to 99.5%. In EBC mashes, a slow decay in enzyme activity was followed by an increased rate of decay after 30 min. The β-glucan concentration in well-modified samples remained steady while enzyme activity was appreciable, though it increased after 40 min. As a result, β-glucan percent extract remained relatively low, ranging from 11.9% to 34.3%. The β-glucanase activity at lower temperatures compensates for high malt β-glucan. Measuring wort β-glucan in an EBC mash is insufficient in predicting malt performance in other mash styles. Methods for β-glucan and β-glucanase analysis adapted for the Gallery autoanalyzer increased throughput, enabling analysis of the enzyme and substrate throughout mashing.

Technological features of Saccharomyces cerevisiae var. boulardii for potential probiotic wheat beer development

A comparative controlled study was carried out to evaluate the performance of Saccharomyces cerevisiae var. boulardii to act as brewer's yeast for potential probiotic beer production. The yeast performance on the beer wort (cell growth, sugar consumption and products production) was compared with the conventional top-fermentation Saccharomyces cerevisiae. To improve the yeast metabolism, changes were made in the malt concentration of the wort recipe and in the ramp mash temperature profile, emphasizing β-amylase activity to provide high glucose concentration in the wort. Next, metabolism close to conventional brewer's yeast was achieved. Saccharomyces cerevisiae var. boulardii survivability in the beer and after in vitro gastrointestinal transit was assessed as the indicative of potential probiotic properties in the beer. The yeast population did not decrease dramatically over the storage period, withstanding alive above the minimal dose prescribed to confer health benefit to the host. The present work shows an alternative method to produce potential probiotic wheat beer. However, Saccharomyces cerevisiae var. boulardii metabolism is still not completely understood, especially the metabolism on the wort sugar and the optimized conditions of the wort recipe and ramp mash temperature profile.

Comparisons of Modern United States and Canadian Malting Barley Cultivars with Those from Pre-Prohibition: IV. Malting Quality Assessments Using Standard and Nonstandard Measures

This study was conducted to identify which traits or combination of traits associated with malting quality and mashing performance could best define the differences between and within a population of six pre-Prohibition malting barley varieties and a population of five modern elite malting barley cultivars. To accomplish this, standard and nonstandard metrics of malt quality and of performance during Congress mashing were analyzed by simple linear correlations and multivariate statistics. Analyses of the two populations combined revealed that activities of α-amylase at each time sampled during mashing were positively and significantly correlated with the concentrations of glucose at that same time, were not significantly correlated with maltose concentrations at any time, and were only significantly correlated with maltotriose concentrations for the first 30 min of mashing. Activities of β-amylase were not significantly correlated with concentrations of glucose, maltose, or maltotriose at any time during mashing. Analysis of α-glucosidase activities showed no consistent trends in correlations with either glucose or maltotriose and no significant correlation with maltose at any time. Analysis of limit dextrinase activities showed significant and positive correlations with glucose and maltotriose concentrations prior to the mash temperature reaching the starch conversion stage. Although no individual amylolytic enzyme activity was significantly correlated with maltose concentration, diastatic power was positively and significantly correlated with maltose at five of six times sampled during mashing. Diastatic power was not significantly correlated with glucose or maltotriose concentrations at any time. Malt extract values and osmolyte concentrations were positively and significantly correlated with mash glucose concentrations at all times sampled, with maltose concentrations at the first four times sampled, and with maltotriose for the first five times. Principal component analysis (PCA) of the traits analyzed in the two populations combined showed that the modern malting barleys were generally well separated from the pre-Prohibition barleys by three principal components that accounted for 75% of the variation among the 11 cultivars. The traits that collectively contributed the most to separation of the modern from the pre-Prohibition barleys were osmolyte concentrations, malt extract values and glucose concentration, which were higher in the modern cultivars, and α-glucosidase thermostability and concentrations of maltopentaose, maltohexaose and maltoheptaose, which were higher in the pre-Prohibition cultivars. PCA of the individual populations also separated Tradition from the other modern cultivars due to its lower levels of glucose, maltotriose, and α-amylase activity and by its higher levels of maltose and % plump. PCA of the pre-Prohibition population separated Hanna from the other pre-Prohibition cultivars primarily by its higher levels of maltopentaose through maltoheptaose and its low levels of osmolytes. Silver King was somewhat displaced from other pre-Prohibition cultivars due to its low levels of osmolytes and to its very high levels of α-glucosidase thermostability.

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

Application of quantitative nuclear magnetic resonance spectroscopy to biological acidification of barley mashes

Spontaneous biological acidification has long been a part of the German brewing tradition, and was historically used to optimize the pH of brewhouse mashes. By facilitating the growth of native barley flora, the production of lactic, acetic and succinic acids sours the mash, functioning in a similar way to the addition of food-grade acids, which are prohibited under the Reinheitsgebot of 1516. Traditionally, sour mashes have been performed at the ‘optimum’ temperature of 49 °C. Quantitative proton nuclear magnetic resonance spectroscopy was used for the investigation and quantitation of organic acids produced by acidified mashes over a range of temperatures. All target metabolites demonstrated an inverse relationship with temperature, although lactic acid reached a relative maximum at 49 °C, which is in agreement with the customary sour mash temperature. Therefore, it would seem that the optimization of a sour mash is dependent not on absolute acid concentration, which would give the greatest pH regulation potential, but on the relative acid concentration, an important factor influencing the final flavour profile of a beer. Copyright © 2014 The Institute of Brewing & Distilling

Effect of Mashing Temperature on the Processability of Malted Barley

The infusion method used in mashing well-modified malt could be a source of problems associated with malt processing. This study showed that when well-modified barley malt was mashed at an infusion temperature of 65�C the actual internal temperature of the mash was 63�C (65/63�C). Under this mashing condition, good results were obtained for both free amino nitrogen (FAN) products and predicted spirit yield (PSY). Filtration rates were also encouraging because it was possible to collect up to 250 mL of wort in record time. Similarly, when malt was mashed at an infusion temperature of 67�C, the actual internal temperature of the mash was 65�C (67/65�C). Again, good results were obtained for both FAN products and PSY, with a marginal increase of 0.5% obtained for PSY. Filtration rates were also good, because it was possible to collect up to 250 mL of wort in record time. A very strong correlation (R(^2) = 0.9999) was found between filtration rates for infusion mash at 67/65�C and 65/63�C. When the infusion mashing temperature was increased to 69�C, it corresponded to an internal mash temperature of 67�C. Under this infusion mashing condition (69/67�C), a marginal drop in FAN product release occurred, it took longer than 2 h to collect 200 mL of wort, and collection of 250 mL of wort was very difficult to achieve. Although strong correlations were found for filtration rates of infusion mash at 69/67�C versus 65/63�C and infusion mash at 69/67�C versus 67/65�C (R(^2) = 0.975 or 0.973, respectively), a decline was observed compared with infusion mash at 67/65�C versus 65/63�C (R(^2) = 0.9999). The 69/67�C mashing experiment resulted in a decrease of 0.6% for PSY. It appears that a rise in temperature of 2 degrees Celsius in internal mash from 65 to 67�C caused the release of materials that impeded filtration, as well as the release of some materials that were not fermentable. Optimum results were obtained when infusion mashing was performed at 67/65�C.

A Comprehensive Revaluation of Small-Scale Congress Mash Protocol Parameters for Determining Extract and Fermentability

The objective of this study was to comprehensively and methodically evaluate the small-scale mash parameters of the standard Congress (EBC and ASBC) mash protocol in order to modernize this protocol so it better emulates modern commercial brewing practices. For the recommended final 65°C mash protocol, the key parameters were grist milling at 0.7 mm by disc mill, an initial grist/water ratio of 1:3, an initial mash temperature of 65°C, and an initial mashing phase of 65°C for 60 min. Of lesser importance, but still adopted due to widespread use in commercial brewing, was the addition of CaSO4 (0.3 mM) and completion of mashing at 74°C, after which the grist/water ratio was decreased to 1:6 before cooling and lautering. The “final 65°C” mash protocol was compared with the Congress mash protocol and a simple 65°C variant (“old 65°C”) mash protocol to determine the influence of mash protocol on extract and fermentability using a selection of 29 commercial malts. It was demonstrated that the choice of mash protocol applied had subtle, but important, impacts on the determination of extract and prediction of fermentability. Through a relatively simple modification of the small-scale wort production protocol, measurement of malt lautering performance, based on the volume of wort lautered at 25 min, was also proposed. The investigation showed that the mash protocol used could interact with subtle differences in malt characteristics, which could alter the relative importance of the predictive parameters of important malt quality characteristics such as extract, fermentability, and lautering. Researchers and malt quality technicians should be aware that these subtle influences could potentially result in unexpected biases in routine malt analyses and research investigations of components that influence malting and brewing parameters.

Object-oriented modelling and simulation of starch mashing

Abstract In the brewing process, a well-functioning temperature control in the mashing phase is of paramount importance for a good quality of the final product. Given the complexity of the underlying biochemical reactions, a reliable process model can be of great help. However, most of the models developed in the literature are not suited for that task, since the mash temperature is considered an exogenous input. In this work, literature models are complemented with suitable energy balance equations, implemented in the Modelica language, and verified against literature data. A temperature control system is then set up with one of those (first principle) models, to illustrate the usefulness of the idea, including the possibility of simulating the control code up to a quasi-replica setting—i.e., integrating continuous-time and event-based modelling. Future developments will include more extensive use of model-based control techniques, and also the integration of model forecasts and process measurements, to further improve the control results.

Effect of Operational Parameters on the Determination of Laboratory Extract and Associated Wort Quality Factors

Mashing for the determination of malt extract and wort quality factors is one of the most fundamental analyses performed in malting and brewing laboratories. The origins of the Congress mash method date from the late 19th century, and dissatisfaction with the method has sometimes been voiced because the operational parameters do not necessarily reflect current commercial practices. The objective of this study was to evaluate the effect of operational parameters on the laboratory determination of malt extract and associated wort quality parameters. Two current malting cultivars, displaying three modification levels, were used in combination with three levels of grind, three grist/water ratios, and two mash temperature profiles. Grind clearly had the most marked effect and impacted all analytical values. The effects were greatest on extract. Temperature profile also affected all analytical parameters, but its impact was most obvious for wort color, β-glucans, and fermentable sugars. Mash gravity had small effects on soluble protein and free amino nitrogen. Significant interactions involving modification often were observed, suggesting that observed differences were more pronounced as malt modification of samples decreased. The results of this study suggest that although the alteration of the laboratory mash parameters evaluated in this study may change the magnitude of differences between samples it is unlikely to change the overall actual rank of samples.

Microwave heating of apple mash to improve juice yield and quality

The effects of four heat treatments of apple mash on juice yield and quality were evaluated and compared to juice produced from unheated apple mash at 21°C. Fuji and McIntosh apple mashes were heated to bulk temperatures of 40°C, 50°C, 60°C and 70°C in a 2450 MHz microwave oven at 1500 W. Juice yield increased when mash was heated before pressing. Cider produced from the heated mashes had comparable pH, titratable acidity, and sensory characteristics to cider produced from room temperature mashes; however, total phenolic and flavonoid content of the juice increased with increasing mash temperature. Soluble solids and turbidity also increased as treatment temperature increased.

The Impact of the Thermostability of α-Amylase, β-Amylase, and Limit Dextrinase on Potential Wort Fermentability

Diastatic power (DP), a measure of the level of activity of starchhydrolyzing enzymes, is a term that refers to the combined activity levels of β-amylase, α-amylase, limit dextrinase, and α-glucosidase. The result of the action of these enzymes during brewing is to break down starch into component sugars that are readily fermented into alcohol by yeast. Although DP is a reasonable predictor of fermentability, it does not always accurately estimate the level of fermentable sugars generated during mashing or the subsequent fermentability of the resultant wort. Previously, it has been shown that allelic variation in β-amylase thermostability has a significant impact on wort fermentability. The thermostability of the DP enzymes is critical in determining fermentable sugar yield during mashing, where the mash temperature profile is a balance between the temperature required for starch gelatinization to enable efficient hydrolysis and the rate of thermal inactivation of the DP enzymes. This study demonstrates that there is significant variation in the thermostability of α-amylase and limit dextrinase in malts made from a wide range of Australian and international malting barley varieties. This variation in α-amylase and limit dextrinase thermostability combined with that of β-amylase provides an opportunity for barley breeders to produce divergent malting varieties that better fulfill brewers' fermentability requirements. The implications of the varying DP enzyme thermostability on the selection of malt by brewers to optimally suit different brewing styles and regimens are outlined.

The Effect of Mashing on Malt Endoproteolytic Activities

During malting and mashing, the proteinases of barley (Hordeum vulgare L.) and malt partially hydrolyze their storage proteins. These enzymes are critical because several aspects of the brewing process are affected by the soluble proteins, peptides and/or amino acids that they release. To develop improved malting barleys and/or malting and brewing methods, it is imperative to know whether and when the green malt endoproteinases are inactivated during malting and mashing. These enzyme activities are totally preserved during kilning and, in this study, we have determined when they were inactivated during mashing. Samples were removed from experimental mashes that mirrored those used in commercial breweries and their endoproteolytic activities were analyzed. The malt endoproteinases were stable through the 38 degrees C protein rest phase, but were quickly inactivated when the mash temperature was raised to 72 degrees C for the conversion step. All of the proteinase activities were inactivated at about the same rate. These findings indicate that the soluble protein levels of worts can be varied by adjusting the protein rest phase of mashing, but not by altering the conversion time. The rates of hydrolysis of individual malt proteins probably cannot be changed by altering the mash temperature schedule, since the main enzymes that solubilize these proteins are affected similarly by temperature.

Quick Fiber Process: Effect of Mash Temperature, Dry Solids, and Residual Germ on Fiber Yield and Purity

ABSTRACTPreliminary calculations showed that recovery of fiber before fermentation in the dry grind ethanol facilities known as the Quick Fiber process increases fermenter capacity and reduces ethanol production cost by as much as 4 ¢/gal. The objective of the current research was to evaluate the effect of mash temperature, dry solids, and residual germ on fiber yield and purity when using the quick fiber process. Fiber was recovered by flotation and skimming, while maintaining a specified temperature, dry solids, and residual germ in the mash. Varying temperature and dry solids in the mash resulted in a statistically significant effect on the fiber yield, neutral detergent fiber (NDF) content, and weight of NDF/100 g of dry corn. Varying residual germ in the mash resulted in statistically significant differences for NDF through dilution and the weight of NDF/100 g of dry corn. The highest fiber yield was 10.9% at 45°C, 23% dry solids, and 15% residual germ; the highest NDF was 50.9% at 30°C, 21% dry solids, and 0% residual germ. The highest weight of NDF/100 g of dry corn was observed at 45°C, 23% dry solids, and 0% residual germ.

Decanter centrifugation of apple mash: effect of centrifuge parameters, apple variety and apple storage

Enzyme treated (0·02% Pectinex Ultra SP, 40°C, 3–4 h) apple mash gave juice yields of 80–90% with suspended solids <3% when decanter centrifuged. Centrifugal conditions were a 230 mm bowl, 5696 rev/min, pool depth of 39 mm and mash temperature of 40°C. Capacities were 0·33–0·39 kg/s (2600–3100 lb/h) under appropriate conditions for Red Delicious, Spartan, McIntosh and Golden Delicious apples. Storage in air at 0–1°C for 8 months did not affect machine capacity with Red Delicious and McIntosh varieties but storage of Spartan and Golden Delicious varieties beyond 3–4 months resulted in markedly reduced (half or less) machine capacities. The effects of varying decanter centrifuge settings and problems associated with decanter separation of apple juice are documented and discussed.

Application of fuzzy control theory to the sake brewing process

Abstract Know-how of skilled operators concerning the management of the traditional sake brewing process was analyzed using fuzzy control theory, and arranged as production rules having the following four fuzzy variables: if (DB = DBi) & (DD = DDi) & (AL = ALi) then (CT = CTi). Membership functions of DB and DD were arranged in real-time using a kinetic model proposed by us previously. Based on these control rules, a fuzzy control system for regulating the moromi (sake mash) temperature was constructed. A computer simulation of sake brewing indicated that the proposed control system could be applied to control the temperature along the desired curve of traditional sake brewing.

無蒸煮穀類を用いた食酢の製造

Alcohol fermentation of uncooked corn and rice grain at a mash temperature between 20°C and 25°C resulted in less dissolution of nitrogeneous substances and a lower production of lactic acid. But the alcohol yield was not affected by this control. Proteinase is usually contained in commercial glucoamylase preparations. In alcohol fermentation of uncooked rice grain, proteinase-free glucoamylase had a depressive effect on the production of lactic acid and dissolution of nitrogeneous substances, and the rate of alcohol fermentation was significantly reduced, but this enzyme showed no effect on alcohol fermentation of uncooked corn grain. The lactic acid produced and nitrogeneous substances dissolved in the alcohol fermented beer of corn or rice seemed to lead to formation of acetoin and several volatile acids in the acetic acid fermentation, because the amounts of these substances were roughly in parallel with those of the former substances.

Application of a Commercial Barley Beta-Amylase in Brewing

Food-grade barley β-amylase, commercially available in bulk, was tested on the laboratory and pilot-plant scale to evaluate its potential utility in mashing. When mash temperature was varied betwee...

Application of a Commercial Barley β-Amylase in Brewing

Food-grade barley β-amylase, commercially available in bulk, was tested on the laboratory and pilot-plant scale to evaluate its potential utility in mashing. When mash temperature was varied between 60 and 80° C and adjunct ratio between 0 and 98%, wort fermentability was affected more than extract yield. Therefore, mashing appears to be a β-amylase limited process. When used in the fermentation, barley β-amylase markedly increased fermentability and may find special application in the production of reduced dextrin beers.

Nucleic Acid Degrading Enzymes of Barley Malt. I. Nucleases and Phosphatases

Seven enzymes involved in the degradation of nucleic acids and nucleotides were studied in barley and during germination, kilning, and mashing. Among these enzymes were deoxyribonuclease (DNase), two ribonucleases (RNase) (sensitive and insensitive to ethylenediaminetetraacetic acid), phosphodiesterase, 3′- and 5′-nucleotidases, and phosphomonoesterase. The levels of all of the enzymes were low in mature barley and remained low during steeping, but large increases in activity were observed during 10 days of germination. Application of gibberellic acid in the steep had a statistically significant effect on DNase, phosphodiesterase, and phosphomonoesterase. All of the enzymes were quite stable during kilning for 24 hr at 45°C. Phosphodiesterase, 3′-and 5′-nucleotidases, and phosphomonoesterase showed good temperature stability during kilning at 65 and 85° C, whereas DNase and the RNases showed slight losses at these temperatures. The RNases were unstable even at low mash temperatures, and their activities declined very rapidly as the mash temperature rose to 70° C. DNase was more stable than the RNases and had a slower decline in activity as the temperature rose to 70°C. Phosphomonoesterase and the 3′- and 5′-nucleotidases were similar to the nucleases in temperature stability. Only a low level of phosphodiesterase activity was extracted during mashing. Commercial brewers' malts had high levels of these enzymes compared to experimental malts.

Precipitation of Protein during Mashing: Evaluation of the Role of Calcium, Phosphate, and Mash pH

In a temperature-programmed mash, malt protein first dissolved during the protein rest, then decreased in concentration as the mash temperature approached 70° C. With a technique called grain-out m...