Variation in quality of grains used in malting and brewing

Cereal grains have been domesticated largely from food grains to feed and malting grains. Barley (Hordeum vulgare L.) remains unparalleled in its success as a primary brewing grain. However, there is renewed interest in "alternative" grains for brewing (and distilling) due to attention being placed on flavor, quality, and health (i.e., gluten issues) aspects that they may offer. This review covers basic and general information on "alternative grains" for malting and brewing, as well as an in-depth look at several major biochemical aspects of these grains including starch, protein, polyphenols, and lipids. These traits are described in terms of their effects on processing and flavor, as well as the prospects for improvement through breeding. These aspects have been studied extensively in barley, but little is known about the functional properties in other crops for malting and brewing. In addition, the complex nature of malting and brewing produces a large number of brewing targets but requires extensive processing, laboratory analysis, and accompanying sensory analysis. However, if a better understanding of the potential of alternative crops that can be used in malting and brewing is needed, then significantly more research is required.

From the Raw Materials to the Bottled Product: Influence of the Entire Production Process on the Organoleptic Profile of Industrial Beers

In the past few years, there has been a growing demand by consumers for more complex beers with distinctive organoleptic profiles. The yeast, raw material (barley or other cereals), hops, and water used add to the major processing stages involved in the brewing process, including malting, mashing, boiling, fermentation, and aging, to significantly determine the sensory profile of the final product. Recent literature on this subject has paid special attention to the impact attributable to the processing conditions and to the fermentation yeast strains used on the aromatic compounds that are found in consumer-ready beers. However, no review papers are available on the specific influence of each of the factors that may affect beer organoleptic characteristics. This review, therefore, focuses on the effect that raw material, as well as the rest of the processes other than alcoholic fermentation, have on the organoleptic profile of beers. Such effect may alter beer aromatic compounds, foaming head, taste, or mouthfeel, among other things. Moreover, the presence of spoilage microorganisms that might lead to consumers' rejection because of their impact on the beers' sensory properties has also been investigated.

Proteome Phenotypes Discriminate the Growing Location and Malting Traits in Field-Grown Barley

Barley is one of the key cereal grains for malting and brewing industries. However, climate variability and unprecedented weather events can impact barley yield and end-product quality. The genetic background and environmental conditions are key factors in defining the barley proteome content and malting characteristics. Here, we measure the barley proteome and malting characteristics of three barley lines grown in Western Australia, differing in genetic background and growing location, by applying liquid chromatography-mass spectrometry (LC-MS). Using data-dependent acquisition LC-MS, 1571 proteins were detected with high confidence. Quantitative data acquired using sequential window acquisition of all theoretical (SWATH) MS on barley samples resulted in quantitation of 920 proteins. Multivariate analyses revealed that the barley lines' genetics and their growing locations are strongly correlated between proteins and desired traits such as the malt yield. Linking meteorological data with proteomic measurements revealed how high-temperature stress in northern regions affects seed temperature tolerance during malting, resulting in a higher malt yield. Our results show the impact of environmental conditions on the barley proteome and malt characteristics; these findings have the potential to expedite breeding programs and malt quality prediction.

From Ground to Glass: Evaluation of Unique Barley Varieties for Craft Malting, Craft Brewing, and Consumer Sensory

Differentiating agricultural products has been adopted as a strategy to improve farm profitability and thereby business sustainability. This study aimed to evaluate unique barley varieties for craft malting and brewing markets to enhance profitability for diversified grain growers in southwestern Washington. Advanced barley breeding lines from Washington State University (WSU) were compared to a control variety (CDC-Copeland) through field trials, experimental and commercial malting conditions, and consumer sensory evaluation. The beers differed only by the genotype-dependent malt. Malting conditions (experimental or commercial) and field replicate influenced five out of the eight malt quality traits measured, while genotype influenced seven out of eight of the traits. Consumers differentiated the beers through ranking, open description, and check all that apply during a central location test. Based on consumer liking, breeding lines 12WA_120.14 or 12WA_120.17 could replace CDC-Copeland in beers. A total of 83% of consumers responded that they would pay more for a beer if it would support local farmers. This value proposition represents an opportunity for consumer purchasing to support producers, who form the foundation of the craft malt and beer value chain and whose economic success will determine the sustainability of small farms in minor growing regions. We provide further evidence for the contributions of barley genotype to beer flavor, while tracing the impact of barley genotype from ground to glass.

Aroma and color development during the production of specialty malts: A review

Specialty malts comprise a promising field for innovative approaches concerning their potential in terms of color, aroma, and taste influence on the composition of beer and other beverages. Nevertheless, poor reproducibility of aroma and taste is a recurrent struggle between maltsters, leaving color as a practical parameter for quality control. However, malts with similar coloration can present distinct aroma profiles, leaving open questions concerning key aroma compounds, their dynamic responses to malting process variations and to what extent they may vary in a certain color range. Key aroma volatiles have been identified in the matrix of barley malt, comprising a variety of products of non-enzymatic browning reactions (e.g., caramelization, pyrolysis, and Maillard reactions). Here, water plays a crucial role together with the intensity of the temperature regimes. Nevertheless, the final aroma profile of a malt product is the result of a balance between aroma formation and losses. Therefore, the correlation between color and aroma is of big complexity. That being the case, the present article questions if key aroma compounds responsible for the peculiar flavors of specialties have been defined by scientific literature and whether their production dynamics is unveiled. In this manner, this work proposes an overview of the aroma compounds present in specialty malt products studied up to the current date. More specifically, the process production of specialty malts and its potential impact on the formation of aroma and taste is studied alongside the key aroma-active compounds, their correlation to color, and trending analytical techniques for aroma and color assessment.

Autochthonous Biological Resources for the Production of Regional Craft Beers: Exploring Possible Contributions of Cereals, Hops, Microbes, and Other Ingredients

Selected biological resources used as raw materials in beer production are important drivers of innovation and segmentation in the dynamic market of craft beers. Among these resources, local/regional ingredients have several benefits, such as strengthening the connection with territories, enhancing the added value of the final products, and reducing supply costs and environmental impacts. It is assumed that specific ingredients provide differences in flavours, aromas, and, more generally, sensory attributes of the final products. In particular, of interest are ingredients with features attributable and/or linked to a specific geographical origin. This review encompasses the potential contribution and exploitation of biodiversity in the main classes of beer inputs, such as cereals, hops, microbes, and adjuncts, with a specific emphasis on autochthonous biological resources, detailing the innovative paths already explored and documented in the scientific literature. This dissertation proposes an overview of the impact on beer quality for each raw material category, highlighting the benefits and limitations that influence its concrete applications and scale-up, from the field to the stain. The topics explored promote, in the sector of craft beers, trends already capitalised in the production of other alcoholic beverages, such as the preservation and revalorisation of minor and autochthonous varieties, the exploitation of yeast and bacteria strains isolated from specific sites/plant varieties, and the valorisation of the effects of peculiar terroirs on the quality of agricultural products. Finally, the examined tendencies contribute toward reducing the environmental impacts of craft beer manufacturing, and are in line with sustainable development of food systems, increasing the economic driver of biodiversity preservation.

Molecular Insights into the Contribution of Specialty Barley Malts to the Aroma of Bottom-Fermented Lager Beers

Specialty barley malts provide unique aroma characteristics to beer; however, the transfer of specialty malt odorants to beer has not yet been systematically studied. Therefore, three beers were brewed: (1) exclusively with kilned base barley malt, (2) with the addition of a caramel barley malt, and (3) with the addition of a roasted barley malt. Major odorants in the beers were identified by aroma extract dilution analysis followed by quantitation and calculation of odor activity values (OAVs). The caramel malt beer was characterized by outstandingly high OAVs for odorants such as (E)-β-damascenone, 2-acetyl-1-pyrroline, methionol, 2-ethyl-3,5-dimethylpyrazine, and 4-hydroxy-2,5-dimethylfuran-3(2H)-one, whereas the highest OAV for 2-methoxyphenol was obtained in the roasted malt beer. Quantifying odorants in the malts revealed that the direct transfer from malt to beer played only a minor role in the amount of malt odorants in the beers, suggesting a substantial formation from precursors and/or a release of encapsulated odorants during brewing.

Strategic malting barley improvement for craft brewers through consumer sensory evaluation of malt and beer

American craft brewers are targeting barley malt as a novel source of flavor and as a means of differentiation. However, fundamental tools have only recently emerged to aid barley breeders in supporting this effort, such as the hot steep malt sensory method, a wort preparation method recently approved by the American Society of Brewing Chemists for evaluation of extractable malt flavor. The primary objective of this study was to determine if insights into beer liking and sensory attributes can be gained through hot steep malt sensory using an untrained panel of craft beer consumers (n = 95). We evaluated consumer acceptance of hot steep and beer samples of different barley genotypes using a 9-point hedonic scale, check-all-that-apply (CATA), and open comment during separate sensory panels. Beers brewed with Washington State University breeding lines (n = 4), selected for all-malt craft brewing, generally had higher consumer acceptance than the industry-standard control variety (CDC Copeland). Genotype had a significant influence on the consumer acceptance of beer aroma, appearance, taste/flavor, sweetness, and overall liking but only on hot steep appearance. Significant differences between genotypes were found for 18% (fruity and other) and 46% (chemical, citrus, earthy, fruity, stale, and sweet aromatic) of CATA attributes for the hot steep and beer panels, respectively. Hot steep and beer liking and sensory attributes had low correlation coefficients. For example, beer overall liking was negatively correlated with chemical (r = -0.338, p < 0.0001) and positively correlated with fruity (r = 0.265, p < 0.0001). This study demonstrates that untrained craft beer consumers can better differentiate among genotypes using beers than hot steep samples. PRACTICAL APPLICATION: In general, Washington State University barley breeding lines had higher consumer acceptance than the control variety, CDC Copeland. Each genotype had a distinctive beer flavor profile, such as 12WA_120.14 (fruity and sweet aromatic), which had the highest consumer acceptance ratings, and 10WA_107.43 (citrus), which has been released as the variety "Palmer." The results illustrate that the use of different barley genotypes presents varied sensory properties in the final beer and that particular malt and beer sensory attributes may influence consumer acceptance.

The Impact of Terroir on the Flavour of Single Malt Whisk(e)y New Make Spirit

The impact of barley variety and its geographical growth location (environment) on the flavour of new make spirit was investigated to determine if "terroir" can be applied in the production of single malt whisk(e)y. New make spirits were produced at laboratory scale under controlled conditions from two different barley varieties (Olympus and Laureate) grown at two distinct environments (Athy, Co Kildare and Bunclody, Co Wexford) in Ireland over two consecutive seasons (2017 and 2018). The spirit samples were analysed by gas chromatography mass spectrometry olfactometry and descriptive sensory analysis. Forty-two volatiles were detected with eight deemed as very influential and fifteen deemed as influential to the aroma of new make spirit. Sensory attributes were influenced by barley variety, environment, and the interactions thereof over both seasons, with environment and the interaction of variety x environment having a greater impact than variety alone. Chemometric analysis of the olfactometry and sensory data found that both environment and season had a greater impact on the aromatic sensory perception of the new make spirits than variety alone. Therefore, this study clearly demonstrates a "terroir" impact on the flavour of new make spirit and highlights its potential importance especially in relation to single malt whisk(e)y.

Assessing the impact of corn variety and Texas terroir on flavor and alcohol yield in new-make bourbon whiskey

The whiskey industry is dominated by whiskey styles with recipes that contain corn as the primary grain. However, little research has been conducted to investigate whiskey specific distinctions arising from different corn varieties and growing environments (i.e. terroir). Further, no studies have investigated the aroma or flavor impacts of different varieties and terroirs. Here, three different commodity yellow dent hybrid corn varieties were grown on different farms in Texas, spanning from the Texas Panhandle to the Mexico-United States border. Using novel small-batch mashing techniques, a newly developed new-make (i.e. unaged whiskey,immediate by-product of distillation) bourbon sensory lexicon, a trained sensory panel, high-performance liquid chromatography, and gas chromatography-mass spectrometry/olfactometry (GC-MS/O), we report for the first time a method for evaluating sample effects on alcohol yield and flavor in new-make bourbon whiskey. We discover that variety, terroir and their interactions, previously ignored, can substantially affect valuable sensory aspects of whiskey, suggesting the importance of scientifically evaluating corn genetics and agronomy for developing better whiskey. Excitingly, our data suggest milled corn with higher levels of benzadehyde, readily measured by GC-MS/O, correlates with improved sensory aspects of distillate, which must be expensively evaluated using a trained human sensory panel.

Mapping of agronomic traits, disease resistance and malting quality in a wide cross of two-row barley cultivars

Wide crosses between genetically diverged parents may reveal novel loci for crop improvement that are not apparent in crosses between elite cultivars. The landrace Chevallier was a noted malting barley first grown in 1820. To identify potentially novel alleles for agronomic traits, Chevallier was crossed with the modern malting cultivar NFC Tipple generating two genetically diverse recombinant inbred line populations. Genetic maps were produced using genotyping-by-sequencing and 384-SNP genotyping, and the populations were phenotyped for agronomic traits to allow the identification of quantitative trait loci (QTL). Within the semi-dwarf 1 (sdw1) region on chromosome 3H Chevallier conferred increased plant height and reduced tiller number, with QTL for these traits explaining 79.4% and 35.2% of the phenotypic variance observed, respectively. Chevallier was also associated with powdery mildew susceptibility, with a QTL on 1H accounting for up to 19.1% of the variance and resistance at this locus most likely resulting from an Mla variant from Tipple. Two novel QTL for physiological leaf spotting were identified on 3H and 7H, explaining up to 17.1% of the variance and with the Chevallier allele reducing symptom severity on 7H. Preliminary micromalting analysis was also undertaken to compare the malting characteristics of Chevallier and Tipple. Chevallier malt contained significantly lower levels of both α-amylase and wort β-glucan than Tipple malt, however no significant differences were observed for the remaining malting parameters measured. This suggests that the most obvious improvements in barley since the introduction of Chevallier are for agronomic traits such as height, yield and lodging resistance rather than for malting characteristics. Overall, our results demonstrate that this wide cross between Chevallier and Tipple may provide a source of novel QTL for barley breeding.

A Review on the Source of Lipids and Their Interactions during Beer Fermentation that Affect Beer Quality

The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour potential. In addition, beer foam stability can be influenced by the concentration of lipids as well as other factors such as hop acids (e.g., iso-α-acids), proteins, polysaccharides and the presence of metal ions (e.g., nickel). Lipids can also influence yeast protease activity as well as the production of ethanol. This review provides an overview of the effect of climate change on the chemical composition of barley in relation to lipids and the influence of lipids in the process of this raw material in order to produce beer.