Lautering Performance Research Articles

​Mashing with Unmalted Buckwheat Influence of Proportion Grind Size, and Exogenous Enzymes on Small Scale Lautering Performance

​Mashing with Unmalted Buckwheat Influence of Proportion Grind Size, and Exogenous Enzymes on Small Scale Lautering Performance

Mashing with Unmalted Buckwheat Influence of Proportion, Grind Size, and Exogenous Enzymes on Small-Scale Lautering Performance

Mashing with Unmalted Buckwheat Influence of Proportion, Grind Size, and Exogenous Enzymes on Small-Scale Lautering Performance

A Glycoside Hydrolase Family 62 A-L-Arabinofuranosidase from Trichoderma Reesei and Its Applicable Potential during Mashing.

Arabinoxylan is the second most abundant component in the endosperm cell wall of barley and it has been shown to have negative effects on the viscosity and filtration rate of wort and beer. In this study, a glycoside hydrolase (GH) family 62 α-L-arabinofuranosidase (AFase), termed as TrAbf62A, was purified from the culture filtrate of Trichoderma reesei CICC 41495 by a combined chromatographic method. The preferred substrates of the purified TrAbf62A were soluble, highly substituted arabinoxylan oligosaccharides and polymers, similar to the type found in barley grain. TrAbf62A exhibited activity towards oligomeric and polymeric arabinoxylans, as well as colorimetric arabinose-based substrates, thus meeting the criteria to be classified as a type B AFase. TrAbf62A released mainly arabinose and xylose from soluble wheat arabinoxylan, thus indicating a dual lytic enzyme activity. Supplementation of TrAbf62A during mashing, with a loading of 12 mU/g malt, resulted in a 36.3% decrease in arabinoxylan polymer content, a 5.6% reduction in viscosity, and finally, a 22.1% increase in filtration rate. These results revealed that TrAbf62A has a high potential value in improving lautering performance during mashing.

Validation of a high-performance size-exclusion chromatography method to determine and characterize β-glucans in beer wort using a triple-detector array

Beer wort β-glucans are high-molecular-weight non-starch polysaccharides of that are great interest to the brewing industries. Because glucans can increase the viscosity of the solutions and form gels, hazes, and precipitates, they are often related to poor lautering performance and beer filtration problems. In this work, a simple and suitable method was developed to determine and characterize β-glucans in beer wort using size exclusion chromatography coupled with a triple-detector array, which is composed of a light scatterer, a viscometer, and a refractive-index detector. The method performances are comparable to the commercial reference method as result from the statistical validation and enable one to obtain interesting parameters of β-glucan in beer wort, such as the molecular weight averages, fraction description, hydrodynamic radius, intrinsic viscosity, polydispersity and Mark-Houwink parameters. This characterization can be useful in brewing science to understand filtration problems, which are not always explained through conventional analysis.

Lautering Performance Prediction from Malt by Combining Whole Near-Infrared Spectral Information with Lautering Process Evaluation as Reference Values

The aim of this study is to predict lautering performance from malt batches. It pursues an innovative approach by combining the total near-infrared (NIR) spectral information content with lautering process evaluation data. For this, multivariate data analysis is applied to combine the information content of whole NIR spectra of malt with lautering process data. Three NIR spectra were taken for each of the 11 single-malt batches of 100% pilsner malt. Additionally, standard laboratory analyses were performed. Standardized lautering processes were carried out, evaluated, and categorized in “good,” “semi,” and “bad.” The 51 lautering process evaluation values, each with three associated NIR spectra, add up to a total of 153 objects employed in building the prediction model. Partial least squares discriminant analysis (PLS-DA) was used for classification and calculating prediction accuracy. The prediction accuracy of the calibration set was 92.7% with only three failed lautering performance predictions. In the test set validation, only one lautering process prediction failed. This results in a prediction accuracy of 90.6% for the calibration model. With this study, the feasibility of NIR spectroscopy in combination with multivariate statistics to predict lautering performance by analysis of malt was proven.

The Impact of Malt Blending on Lautering Efficiency, Extract Yield, and Wort Fermentability

The impact of malt blending on brewing performance in terms of extract, lautering, and fermentability performance was examined in a series of small-scale mashing trials. Malts were blended so that 40–60% of the grist consisted of malt with lower levels of one or more of these malt quality characteristics. With extract, blending resulted in additive improvements between malts of lower and higher levels. In contrast, improvements were synergistic for lautering performance when there was a substantial difference between the lautering performance of the two malts. The markers for synergism in lautering performance were the level of β-glucanase and wort viscosity. Fermentability performance also typically showed synergism between low and high fermentability malts, with the exception of one malt sample whose blend combination showed an unexplained antagonism. The synergism in fermentability performance was achieved when there was a deficiency between the malts for Kolbach index, the diastatic power enzymes, or β-amylase thermostability that compensated for the lack of these components in the lower-fermentability malts. The importance of these blending interactions was discussed in relation to malt quality specifications and achieving consistent and predictable brewing outcomes.

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.

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.

Storage of Malt, Thiol Oxidase, and Brewhouse Performance

An enzyme capable of oxidizing thiol groups and tentatively called thiol oxidase has been isolated from barley and malt. There is also considerable incidence of thiol-removing activity in profoundly denatured extracts of barley, malt, and specialty malts, which may reflect nonenzymic oxidation or nonoxidative binding of thiols. The enzyme is capable of oxidizing cysteine, glutathione, and dithiothreitol and has an alkaline pH optimum. The enzyme decays in malt during storage, and it is suggested that this is the reason why stored malt displays better lautering performance: if allowed to act, the thiol oxidase promotes the cross-linking of gel proteins, which impede wort flow.

The Influence of Starter Cultures on Barley Contaminated with Fusarium Culmorum TMW 4.0754

This study investigates the effects of lactic acid bacteria (LAB) added concomitantly to barley infected with fungal spores or mycelia of Fusarium culmorum TMW 4.0754. The trials were performed in a micromalting plant simulating an industrial malting program. Malt samples were compared with those of nonacidified barley, disinfected nonacidified barley, chemically acidified barley, and barley with additional modified DeMan-Rogosa-Sharpe 4 medium. All control samples had fungal spores and fungal mycelia added. Bacterial cultures were chosen as a result of their enzymatic (proteolytic/amylolytic) activity level or their good acidification properties. The effects of the LAB and Fusarium-infected malts on wort characteristics were investigated. Characteristics such as pH, extract, color, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, and lautering performance of the resultant worts were determined. Results showed that spores of F. culmorum TMW 4.0754 do not affect the quality of malt or wort. The quality of wort was reduced when mycelia of F. culmorum were applied in the presence of LAB or chemical lactic acid leading to slower filtration rates, lower extract, fermentability, TSN, and FAN yields along with higher viscosity levels. These effects seemed to depend mainly on the presence of mycelia together with the content of lactic acid present.

Lactobacillus plantarum and Pediococcus pentosaceus Starter Cultures as a Tool for Microflora Management in Malting and for Enhancement of Malt Processability

Lactobacillus plantarum VTT E-78076 (E76) and Pediococcus pentosaceus VTT E-90390 (E390) starter cultures were added to the steeping water of normal malting barley in order to balance the microbial community and to enhance malt processability. In this study, we also investigated the effects of lactic acid-acidified MRS-spent medium (MRS-LA) on malting performance. Malting trials with five different two-row barley varieties were carried out in 25 kg pilot scale. The starter cultures promoted yeast growth during malting and restricted the growth of harmful bacteria and Fusarium fungi. Furthermore, they had positive effects on malt characteristics. Reduction in wort viscosity and beta-glucan content and enhanced xylanase and microbial beta-glucanase activities were observed. Starter cultures notably improved lautering performance. Some of the beneficial effects were due to the lactic acid and low pH, as similar effects were obtained with MRS-LA. Starter cultures offer a tool for tailoring of malt properties.

Effects of Three Fusarium Species on the Quality of Barley and Malt

In this study, field-grown barley was artificially infected during the heading stage with three Fusarium species, F. culmorum, F. graminearum, and F. poae. The objective was to investigate possible differences among Fusarium species in terms of how severely they affect the quality of barley under Finnish field conditions. Moreover, we studied the effects of heavy infection on corresponding malt quality. Field trials were carried out with two different barley cultivars at two experimental farms. Spike samples collected during the growing period were analyzed for Fusarium infection and moisture content. Total precipitation and temperature data were collected daily. In addition, the harvested barley samples were analyzed for overall microbial flora and for mycotoxins. The infection rate and the amount of mycotoxins produced in the barley samples differed among species. F. graminearum was found to have the most negative effects on barley quality in terms of the studied parameters. Samples were malted in laboratory scale. All three Fusarium species increased the gushing potential of malt. Heavy fungal infection increased the enzyme activities in malt resulting in darker wort color and increased soluble nitrogen and free amino nitrogen content. However, high Fusarium contamination reduced lautering performance.

The Influence of Lactic Acid Bacteria on the Quality of Malt

In this study three strains of lactic acid bacteria were applied during the malting process to evaluate the impact on malt and wort quality. The trials were performed in a micromalting plant simulating an industrial malting programme. The samples were compared to chemically acidified as well as non-acidified malt. Bacterial cultures were chosen with reference to their enzymatic (proteolytic/amylolytic) activity, or their good acidifying properties. The effects of lactic acid bacteria on wort characteristics were investigated and compared to wort produced from 100% unacidified malt. A chemical food grade lactic acid was also used to acidify the barley for comparison purposes. Characteristics such as pH, extract, colour, viscosity, total soluble nitrogen, free amino nitrogen, apparent fermentability, β-glucan and lautering performance of the resultant worts were determined. Results showed improved levels of β-glucanase in the malt although reduced malt friability was observed where LAB was employed. An improved lautering performance, lower wort viscosity and elevated TSN levels were also reported where LAB exhibiting protease activity were applied.

Application of Biological Acidification to Improve the Quality and Processability of Wort Produced from 50% Raw Barley

In this study four strains of lactic acid bacteria (LAB) were chosen to bioacidify a mash containing 50% barley and 50% malt. The strains were isolated from malted and unmalted barley and assayed for extracellular enzymatic activities (proteases, amylases, β-glucanases). The biologically acidified mash was compared to a chemically acidified mash, 100% malt mash un-acidified and 50% malt and 50% barley mash unacidified. Characteristics such as pH, extract, colour, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, β-glucan and lautering performance of the resultant worts were determined. A model lautering system replicating one used in a brewery was designed and built in University College Cork (UCC) to measure the lautering performance of the bioacidified mashes. The new system was compared to the filtration method used in EBC method 4.5.1. Overall the addition of LAB to bioacidify a mash of 50% barley and 50% malt resulted in faster filtration times, which correlated with decreased β-glucan levels. Proteolytic LAB had a positive influence on the quality of wort and resulted in increased FAN levels. Lighter colour worts were observed along with increased extract levels.

Optimum size distribution of sorghum grist for brewing purposes

The effect of particle size distribution of malted sorghum grist on extract yield and lautering performance was assessed. Sorghum grist particle size evaluation was carried out by sieve analysis after milling. The malted sorghum grist with proportions of coarse, fine, and flour particles in the ratio of 0.36: 0.25: 0.39 respectively gave good results in terms of extract yield and filtration rate. The values of 103.05% and 1.42 x 10-4 m3/s were obtained for extract yield and filtration rate respectively. Keywords: Size distribution, Filtration rate, Brewing (Global Journal of Pure and Applied Sciences: 2003 9(2): 259-264)

PREDICTION OF THE LAUTERING PERFORMANCE OF MALT

The lautering performance of malt in a laboratory column can be predicted from the results of a series of simple analytical estimations. For normal commercial malts, prediction of lautering rates requires measurement of particle size after passage through a roller mill, combined with results from a simple sedimentation test. For poorly-modified malts a laboratory scale mashing operation is additionally required. This allows estimation of the volume of fine particles in the exhausted mash bed and a measurement of wort viscosity.