Kolbach Index Research Articles

Barley varieties registered in the Slovak Republic after the harvest of 2023

After the harvest 2023, three varieties were registered in the Slovak Republic after three years of testing: the spring barley variety LG Rhapsody, the two-row winter barley variety Claudia, and the six-row winter barley variety MH Irén. The malting quality was determined for the varieties LG Rhapsody and Claudia. LG Rhapsody gave extract in malt dry matter of 83.2%. Proteolytic modification of this variety was high (Kolbach index 52.3%). The diastatic power (343 WK), the quality of the sweet wort (apparent final attenuation 82.1%), and the cytolytic modification (friability 94% and β-glucan content 60 mg/l) were at an optimal level. In all cases, the variety gave a clear sweet wort. The winter two-row barley variety Claudia gave a sweet wort with an extract of 81.5%. Kolbach index (46.2%) and diastatic power (508 WK) were at optimal levels. The quality of the sweet wort (apparent final attenuation 80.5%) and the cytolytic modification (friability 83% and β-glucan content of the wort 169 mg/l) were at an average level.

Malt Quality Characteristics of Selected Maize Varieties

In tropical and sub-tropical regions, the cultivation of barley is generally very limited and far less viable for brewing. This study was intended to investigate the potential of released maize varieties for malt purpose. Seventeen released maize varieties were collected from Bako, Ambo and Melkassa Agricultural Research Centers. The varieties were investigated for the most critical chemical compositions, germination test and malt quality. AMH-851 variety had the highest crude protein and ash contents. The highest moisture absorption (49.2%) and germination energy (82%) was noticed in MK-1 maize variety. Insignificant variation and less malting loss (0.7g) was noticed for MK-141 and BH-661 varieties. A significant increment in protein content was observed in maize malt compared to the un-malted grain. AMH-851had the highest (13.8%) and MK-2 showed the lowest (11.2%) malt protein content and the highest kolbach index. In its coarse and fine extract contents, BH-661 (69.93%) and BH-540 (69.29%) varieties had the highest and did not show a significant variation. A range of 6.8 to 29.07 wk enzymatic activity was observed among the selected maize malt with the highest for AMH-851 followed by BH-547 and the lowest for Limu variety. It was noticed that maize grains grown in intermediate agro-ecology could be used as potential malt for brewing purpose.

Development of technology for the production of all-purpose buckwheat malt using plasmochemically activated aqueous solutions

The result of the conducted research is the development of buckwheat malt production technology using plasma-chemically activated aqueous solutions. Buckwheat grain with high starch content became the object of research. The main technological problem is obtaining high-quality brewing malt suitable for the production of gluten-free beer. The expediency of using plasma-chemically activated aqueous solutions as an intensifier of the process of germination of buckwheat grains and an effective disinfectant of buckwheat malt has been experimentally proven. It is shown that the use of plasma chemical activation of technological solutions allows to speed up the process of moistening of buckwheat grain by more than 2 times. The energy and germination capacity of buckwheat grains, when using plasma-chemically activated aqueous solutions, underwent positive changes. The effect of increasing the energy of germination was from 8 to 14 %, and the ability to germinate was 2–9 %. The amylolytic activity of buckwheat malt was analyzed, an increase in amylolytic activity in the range of 30–77 units/g was noted. The extractability of buckwheat malt was investigated separately. This indicator increased by 2–9 % depending on the concentration of peroxides in the solution. The Kolbach index also increased by 2–10 %, which indicates an intensive course of proteolysis. The total amount of amino acids in the experimental samples increased by 619 mg/100 g. There was a significant decrease in the viscosity of the wort, which indicates the high solubility of the obtained buckwheat malt. The technology can be applied in the industrial production of brewing malt and sprouted buckwheat grain of functional purpose. The developed buckwheat malting technology will receive priority in the production of environmentally friendly buckwheat malts of universal purpose that are not contaminated with pathogenic microflora

Deciphering the potential of diverse barley genotypes for improving the malt quality

The quality of barley grains and malt significantly influences the fermentation process and the ultimate quality of beer. However, the diverse range of desired quality requirements complicates the selection of suitable malting barley varieties. Achieving a combination of all desirable traits within a single genotype poses a significant challenge. This study aimed to identify the most promising malting genotypes by evaluating the malting potential of 29 barley genotypes, considering various grain (plumpness, hectolitre weight, grain protein, starch and β-glucan content) and malt quality (diastatic power, filtration rate, hot water extract, kolbach index and green malt β-glucanase activity and β-glucan content) traits. Significant genotypic variations were observed for individual grain and malt traits. Low malt β-glucanase activity led to high β-glucan content and low diastatic power, affecting the profile of fermentable sugars in the wort. Therefore, β-glucanase activity and β-glucan content were identified as potential additional selection criteria for producing high-quality malt. A weighted scoring system based on eight quality traits identified ten barley genotypes that outperformed the check varieties. Among them, three genotypes (BL1523 > PL807 > BL1748) exhibited exceptionally higher scores than the check varieties. Furthermore, wort sugar profiling confirmed the potential of these genotypes as valuable contributors to future barley improvement programs aimed at enhancing malt quality.

The impact of terroir on barley and malt quality – a critical review

Why was the work done: With respect to terroir, ‘To be or not to be,’ (Hamlet, Shakespeare) is a key question for maltsters and brewers for malt and beer quality. Terroir is a sparsely studied aspect of malt quality, despite it being an important component of added market-value in wine since ancient times. The ‘sense of place’ imbued by terroir is an expression of the growth of a grape variety in a specific region with respect to local climate, soil, microbiome, elevation/aspect of the vineyard, viticultural and wine making methods. Similar corollaries to wine terroir can be drawn for hops and malting barley. How was the work done: A comprehensive review of the literature was undertaken to identify reports of terroir in barley/malt quality. Where possible, the discussion was extended by consideration of appropriate unpublished data. What are the main findings: The primary influence of terroir on malt is grain protein content (GPC). This appears, in part, to be controlled by the daylength during grain maturation. Increasing day length typical of grain maturation in Australia tends to be associated with a lower GPC, while decreasing daylength during grain maturation in Canada is associated with a higher protein content. GPC is positively correlated with diastatic power, beta-amylase activity and foam positive proteins such as protein Z4 and hordeins. Conversely, GPC is inversely correlated with extract and Kolbach Index (KI). Interestingly, lower protein barley tends to produce higher KI malts that result in wort with greater flavour complexity and desirability. The level of ionic micronutrients (cations, anions) including calcium and zinc are understudied aspects of malt quality. It is evident that there is significant variation in the ionic micronutrient content of malt produced from different international regions and between regions of the same country which would be an expression of terroir. Lastly, the microbiome of barley/malt shows influences of terroir such as the deleterious impacts of Fusarium head blight on malt quality including gushing and mycotoxins. Variation in terroir will also have more subtle impacts, both desirable and undesirable, on malt quality for the contribution of beneficial enzymes (e.g., cell wall degrading enzymes) or for the propensity of barley to impart malt components into wort (e.g., arabinoxylan) that have been implicated in premature yeast flocculation (PYF) and undesirable beer quality. Why is the work important: The concept of terroir in malt quality has important implications for the efficiency of mashing, lautering, fermentation and beer quality.

Effect of ultrasound pretreatment and soaking time on Quinoa malting.

In this study, malt was produced from quinoa seeds using different ultrasound treatment with different intensities (20%, 60%, and 100%), ultrasound times (5, 10, and 15 minutes), and soaking times (2, 6, and 10 hours) at a frequency of 20 kHz. The seeds were soaked in water at 25°C during exposure to ultrasound waves. The results showed that an increase in soaking time led to a higher malting yield and percentage of soluble solids (°Brix), followed by a downward trend. This trend was intensified by longer exposure to ultrasound waves at higher intensities. The interaction effect of ultrasound wave and soaking time on physicochemical properties showed a downward trend, followed by an upward trend in cold-water and hot-water extract yields, reducing sugar, soluble nitrogen, color, and Kolbach index, with increasing levels of the variables. Finally, quinoa malt treated with an ultrasound intensity of 100% for 15 minutes and soaked for 6hours exhibited the best physicochemical characteristics.

Barley varieties registered in the Slovak Republic after the harvest 2022

The study presents the results of technological quality and agronomic characteristics of the spring barley LG Flamenco and winter barley Sonja. These varieties have passed three-year trials within the state varietal trials of the Slovak Republic. At the optimum nitrogen content in unmalted grain, the LG Flamenco variety showed an extract content of 83.2% and the Sonja variety 81.4%. The diastatic power was at the optimum level for both varieties (316 and 411 WK un.). The Kolbach index was at the optimum level (48.3%) for LG Flamenco and 39.6% for Sonja. In the LG Flamenco variety, cell wall degradation was given by a friability value of 88% and a β-glucan content of 192 mg/l. The friability value for the variety Sonja was 82% and the β-glucan content was 193 mg/l. The quality (apparent final attenuation) of the sweet wort was satisfactory for both varieties (81.0%).

Barley varieties registered in the Czech Republic after the harvest 2022

After the 2022 harvest, seven new varieties of malting barley were registered in the Czech Republic. After three years of testing, spring barley varieties Ambiana, Gingko, Kimberly, KWS Thalis, LG Ludvik, LG Rhapsody and RGT Proxima were registered. Based on the results obtained, LG Ludvik was recommended for the production of beer with the protected geographical indication 'České pivo'. This variety showed low activity of proteolytic and cytolytic enzymes and low level of final attenuation. The other spring barley varieties (Ambiana, Gingko, Kimberly, KWS Thalis, LG Rhapsody and RGT Proxima) gave sweet wort with extract content in malt dry matter ranging from 82.6 to 84.6%. The varieties Ambiana, Gingko, LG Rhapsody and RGT Proxima had extract contents of more than 83%. Proteolytic modification was high (Kolbach Index above 50%) in the varieties Gingko, LG Rhapsody and RGT Proxima. The β-glucan content in sweet wort below 100 mg/l was recorded in the varieties Gingko and LG Rhapsody. Cell wall degradation (friability 85–94%) and final attenuation(81.7–83.0%) were at optimum levels in Ambiana, Gingko, Kimberly, KWS Thalis, LG Rhapsody and RGT Proxima. Gingko, Kimberly and LG Rhapsody always produced clear sweet wort. Low to zero lipoxygenase activity was found in KWS Thalis.

Old but still good – Comparison of malting and brewing characteristics of current and historical malting barley varieties

Historical Czech malting barley varieties Chlumecký, Stupický staročeský, Opavský Kneifel, and Diamant were tested in pilot malting and brewing tests (50 L) of 12% pale lager and compared with five Czech barley varieties recommended for the production of the beer with the protected geographical indication ‘České pivo’. The grain yield of the historical varieties (6.00–7.83 t/ha) was lower compared to the current varieties (8.23–9.39 t/ha). The malts from the historical varieties had high nitrogen content (12.45–13.89%), and low extract (75.2–78.6%, proteolytic (Kolbach index 37.4–40.9%) and cytolytic modification (friability 46.2–57.7%) was also low. Apart from lower extract yield and lower beer filtration rate, the experimental malts from the historical varieties were well processable in the pilot brewery. The sensory quality of the beers was very good (overall impression 3.3–3.8 points), fully comparable to beers made from malts from current barley varieties (3.4–3.9 points). Cluster analysis clearly differentiated the sensory profile of beers of historical and current barley varieties. The historical malting barley varieties under study may find their use mainly in the production of regional microbreweries.

Malting process optimization of an Italian common wheat landrace (Triticum aestivum L.) through response surface methodology and desirability approach

Local and alternative raw materials are of growing interest to the malting and brewing industry. These include wheat landraces, old varieties characterized by high protein content and resistance to biotic and abiotic stress. One of the basic ingredients of beer is malt, i.e., a grain that have been subjected to germination under controlled conditions. Malting awakens the seed's physiological activity, thereby triggering its chemical and structural modification. The response surface methodology (RSM) was used to assess the impact of three independent variables (germination time, germination temperature, degree of steeping) on certain traits defining malt quality. Germination time and temperature exerted a major role during the malting experiments. A desirability function was applied to predict the best combination of parameters that would optimize the desired outcomes. After 6 days, at 18 °C and 42 g/100 g, the following results were achieved: extract 81.6% d.m., Kolbach index (KI) 38.3%, free amino nitrogen (FAN) 116 mg/100 g, apparent attenuation limit (AAL) 82.9%. The response surface methodology (RSM) proved to be largely suitable for the optimization of the malting process under study. Its implementation through the R statistics programming language and environment provided an alternative and valuable resource for conducting the statistical analysis and optimization.

Multi-Response Optimization of the Malting Process of an Italian Landrace of Rye (Secale cereale L.) Using Response Surface Methodology and Desirability Function Coupled with Genetic Algorithm.

Rye is used in some applications in the food and beverage industry and for the preparation of functional foods. It is an interesting raw material in malting and brewing due to its characteristic contribution to the beer's color, turbidity, foam and aroma. The aim of this work was to optimize the micro-malting process of a rye landrace. The response surface methodology (RSM) was applied to study the influence of three malting parameters (germination time, germination temperature and degree of steeping) on the quality traits of malted rye. Long germination times at high temperatures resulted in an increase in the extract and Kolbach index. The model for the apparent attenuation limit showed a particular pattern, whereby time and temperature inversely influenced the response. The lowest viscosities were determined in the worts produced from highly modified malts. Optimization of the variables under study was achieved by means of a desirability function and a genetic algorithm. The two methodologies provided similar results. The best combination of parameters to optimize the malting process on the rye landrace under study was achieved at 6 days, 12 °C and 44 g/100 g.

QUALITY ASSESSMENT OF SPRING BARLEY VARIETIES INTENDED FOR MALTING PROCESS

The suitability of a barley grain for malt production depends upon a large number of quality parameters that are crucial for the identification of high-quality malt varieties. The grain and malt technological quality parameters of five samples of four spring malting barley varieties were studied in order to estimate their malting potential. Selected barley varieties proved to be of satisfactory malting quality in terms of analyzed technological parameters. First-class grain percentage in the analyzed samples ranged from 84.9 to 94.6 %. Hectoliter weight reached values from 634.2 to 737.1 g.dm-3. Barley samples also contained a relatively high starch content of 63 to 68 %. Nitrogenous substances ranged from 9.9 to 11.3 % and all tested varieties met the requirement for nitrogen content. These samples were micro-malted and resulting malt was analyzed. All tested malt samples achieved high and satisfactory extract content of 82.4 - 84.3 %. Statistically significant (p<0.05) the highest extract content was confirmed in variety LG Tosca (84.3 %) which was found to be relatively the best technological quality also for its kernel size and optimal starch and protein content. The average value of friability was 98 %. The intensity of proteolytic modification among varieties was satisfactory (Kolbach index 39.18 - 47.17 %). The viscosity of the wort reached values from 1.41 to 1.47 mPa.s-1, varieties provided clear wort in all cases. Based on the results of grain and malt quality parameters it can be concluded that all tested spring barley varieties are suitable for malting process.

Barley varieties registered in the Czech Republic after the harvest of 2021

Ten new varieties of malting barley were registered in the Czech Republic after the 2021 harvest. After four years of testing, the malting barley varieties Fangio and LG Slovan were registered, and after three years of testing, the spring barley varieties Evgenia, Guzel, LG Flamenco, LG Lodestar, LG Sedlak, Schiwago, SY Solar and the winter barley variety Suez were registered. Based on the results obtained, LG Slovan and LG Sedlak were recommended for the production of beer with the protected geographical indication 'České pivo'. These varieties showed low activity of proteolytic and cytolytic enzymes and low level of final attenuation. The other spring barley varieties (Evgenia, Fangio, Guzel, LG Flamenco, LG Lodestar, Schiwago and SY Solar) gave wort with extract contents ranging from 82.5 to 83.6 %, with Guzel, Evgenia, Fangio and Schiwago showing extract contents above 83 %. Proteolytic modification was mostly at an optimal level in these varieties, with only Fangio, Schwago and Guzel having the Kolbach index above 50 %. The β-glucan content in wort below 50 mg/l was recorded for Schiwago and Fangio. The level of final attenuation for these varieties ranged from 80.7 % to 82.8 %, while final attenuation level above 82.5 % was observed for the varieties Fangio and Guzel. LG Lodestar and SY Solar always produced clear wort. Low to zero lipoxygenase enzyme activity was found in LG Lodestar. The winter barley variety Suez gave malt with an average extract content of 81.9 %. Proteolytic modification, cell wall degradation and malt quality were at an optimal level. The β-glucan content was 158 mg/l.

Barley varieties registered in the Slovak Republic after the harvest of 2021

After three years of testing, the spring barley varieties Amidala, Ellinor and LG Belcanto were registered in the Slovak Republic. Extract of the varieties was between 82.3 and 82.8 %. The varieties showed optimal to high levels of proteolytic modification (Kolbach index 48.6 to 49.4 %) and satisfactory to optimal malt quality (final attenuation 80.9 to 81.5 %). Cell wall degradation was optimal (high friability 87 to 92 %). The beta-glucan content of the wort was satisfactory to optimal (174 to 68 mg/l).

Malting and Wort Production Potential of the Novel Grain Kernza (Thinopyrum intermedium)

As the environmental impacts of beer are of increasing concern to maltsters, brewers, and consumers, perennial cereal crops can offer a more sustainable solution. One new cereal species of interest to the brewing industry is intermediate wheatgrass (Thinopyrum intermedium subsp. intermedium), developed by The Land Institute, in Salina, Kansas, U.S.A., under the branded name Kernza®. It has been touted as a more sustainable alternative to barley and wheat in its requirements for less water and nutrient additions and reduced tilling of agricultural fields. To date, no published research has been performed to assess the potential for this grain for the malt and beer industries as a barley replacement. Here, the “M5” variety Kernza grain was micromalted and the finished malt was compared with both the raw grain and to a reference raw and malted barley (Hordeum vulgare L. var. Copeland). All samples were analyzed for starch gelatinization temperatures via differential scanning calorimetry, amino acid composition, alpha-amylase, diastatic power (DP), total and soluble nitrogen and protein, Kolbach Index (KI), extract, wort free alpha-amino nitrogen (FAN), wort β-glucan, wort color, pH, and clarity. The Kernza malt produced sufficient extract and FAN for typical fermentations with low β-glucan content. However, extract and FAN in the Kernza malts were lower than in the barley reference, and the Kernza worts exhibited higher levels of undesirable soluble protein and haze. Interestingly, the DP for both the raw and malted Kernza were similarly high, indicating that both of the raw grains exhibit high enzymatic activity, which malting did not increase substantially. Results support that Kernza could be an acceptable candidate for malting and subsequent wort production; however, specific techniques may be required to utilize this malt most effectively. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2022.2026662 .

Influence of Variety and Nitrogen Fertilization on the Technological Parameters of Special Malts Prepared from Naked and Hulled Oat Varieties

Grains of four naked oat varieties (Amant, Maczo, Polar and Siwek) and one hulled oat variety (Kozak) from three consecutive years (2018, 2019 and 2020), grown under three different nitrogen fertilization regimes (40, 60 and 80 kg of nitrogen per hectare) were malted and then mashed in the laboratory conditions for the first time; this was carried out to determine whether hulled and naked oat grains possess favourable properties as a raw material for the production of malt. Most of the analysed samples possess a favourable Kolbach index (39.06–46.82%), good extractivity (81.07–81.97%) and rather good saccharification time (13.33–26.67 min); however, some disadvantages of the produced malts could be pointed out. During the congress mashing, the filtration time of the worts produced from the hulled and naked oat malts was long (96.67–110 min) and the wort volume was not satisfactory (155–228.53 mL). Subsequent studies over oat malting and mashing need to be performed to maximize oat potential as the raw material for the production of the malt.

A Malting Barley (Hordeum Vulgare L.) Variety, ‘Nurimaeg’ with Resistance to Barley Yellow Mosaic Virus and Tolerance to Lodging Stress

Other SectionsAbstract서 언재료 및 방법결과 및 고찰적 요사 사FigureTableReferenceA malting barley variety, ‘Nurimaeg’, was developed with resistance to barley yellow mosaic virus (BaYMV), tolerance to lodging stress, and good brewing quality. ‘Nurimaeg’ was developed by crossing Milyang127 and Miharu gold in 2004. Regional yield trials were conducted for ‘Nurimaeg’ as a breeding line ‘Iksan175’ in four different regions from 2014-2016. It has a type I growth habit, and its average heading and maturity dates were April 12 and May 20, respectively-which were 1 day later than the maturity date of ‘Hopum’ variety. As ‘Nurimaeg’ has a shorter culm length (77 cm) than that of ‘Hopum’, it showed tolerance to lodging stress. This variety possesses the rym5 gene and is resistant to BaYMV. It showed a 42.9 g 1000-grain weight and 90% assortment ratio. The yield potential of ‘Nurimaeg’ was 408 kg/10a, which is approximately 18% higher than that of ‘Hopum’. Analysis of grain quality for malting showed that ‘Nurimaeg’ has high quality of low protein and β-glucan content. Malt quality analysis revealed that it has 72.8% extract, 4.2% soluble protein, 38.9% kolbach index, and 243 WK diastatic power, which all were similar to those of ‘Hopum’. ‘Nurimaeg’ would be suitable for cultivation in the areas of Korea that have a daily minimum temperature of -4℃ in the month of January (Registration No. 7960).Keywords : malting barley, BaYMV resistance, lodging resistance, malt, variety

Effect of malting process duration on malting losses and quality of wheat malts

Abstract The study assesses impact of malting process duration on malting losses and quality of malts obtained from three varieties of winter wheat, i.e., Elixer, Rockefeller and Gimantis. The findings show that increased duration of the malting process (from 4 to 7 days) corresponded to greater total weight loss, with the most significant differences observed between 5-day and 6-day wheat malts. The qualitative analysis of the malts was carried out in accordance with EBC methodology. The assessments showed that the 5-day long malting process applied to the relevant wheat varieties resulted in production of high-quality malt with optimum malting losses observed in the case of Elixer and Rockefeller varieties. Slightly higher malting losses were identified in the case of Gimantis, and the malt obtained from this variety had very high contents of soluble protein (on average 5.34% d.m.) and Kolbach Index (average of 50.49%), which reflects high proteolytic activity during the grain malting process and a need to modify the malting process for this variety.

Malting Quality of ICARDA Elite Winter Barley (Hordeum vulgare L.) Germplasm Grown in Moroccan Middle Atlas

The use of barley (Hordeum vulgare L.) in Morocco is still limited to food and feed despite the amplified demand by local industries for imported malt. This study aims to evaluate 36 barley elite lines for major grain physicochemical parameters and malt quality traits. Analysis of variance, Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA) were performed. The results showed significant genotypic variation among genotypes for individual grain and malt traits. High broad sense heritability was obtained for all traits except for plump grain percentage, malt friability, and germination capacity. Starch, malt extract, Kolbach index, grain area, and test weight correlated significantly and negatively with barley protein. Malt extract correlated positively with Kolbach index and starch, but a negative correlation with soluble protein and malt protein was found. Based on 12 characters, 77% of the total genotypic variation was explained by the three first principal components following PCA and four clusters were depicted based on HCA. Genotypes of high interest with desirable levels of quality standards were identified to be used as a malt quality traits donor while designing crossing programs. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.1978036 .

Barley varieties registered in the Czech Republic after the harvest of 2020

The study presents malting quality and agronomic characteristics obtained during testing of barley varieties in the Czech Republic. After the harvest of 2020, the following spring barley malting varieties were registered: Amidala, Focus, Greenway, KWS Jessie, LG Belcanto, and LG Stamgast. LG Stamgast was recommended for production of the beer with the protected geographical indication České pivo. In addition, the non-malting spring barley variety RGT Gagarin was registered. Amidala, Focus, Greenway, KWS Jessie, LG Belcanto provided malt with the extract content over 83%. These varieties also easily degraded nitrogenous substances. The value of the Kolbach index ranged from 48.6 to 52.1%. Diastatic power was at the optimal level. Degradation of cell walls was also optimal. Friability moved from 89 to 97% and β-glucan content in wort achieved satisfactory values of 65 – 170 mg/l in the given varieties . Wort quality, which is characterized by final attenuation, was at the above average to optimal level of 80.9 – 83.2% in these varieties of spring barley. LG Stamgast showed lower values of proteolytic and cytolytic modification and lower values of final attenuation, which is required for the varieties recommended for the production of the beer with the protected geographical indication České pivo.