Production Process on Organoleptic Profile of Industrial Beers

Version	Summary	Created by	Modification	Content Size	Created at	Operation
1		Remedios Castro Mejías	--	3375	2022-11-10 19:59:45	\|
2	update references and layout	Amina Yu	+ 2 word(s)	3377	2022-11-11 03:13:23	\|

This entry is adapted from the peer-reviewed paper 10.3390/foods11203215

Beer is one of the most popular and commonly consumed alcoholic beverages worldwide. However, a remarkable transition has been taking place regarding consumersʹ preference for traditional ‘tasteless’ beers, to more complex craft beers, with a growing quota of consumers being interested in new beer styles that exhibit novel sensory characteristics. In addition, a growing consumer segment, comprising people between 21 and 30 years old, seems to be interested in new beer tastes and is willing to pay for these tasty beers, even if more expensive. For this reason, brewers and researchers are investigating the use of alternative raw materials and processing conditions over the different stages of beer brewing so that its organoleptic profile is enhanced.

brewing maturation aging spoilage microorganisms

1. Barley, Malt and Malting

Barley (Hordeum vulgare L.) is the most commonly used cereal in beer production, and its endosperm represents the main tissue of the grain, which is mainly composed of starch granules (62.7% of the total grain weight) embedded in a protein matrix ^[1]^[2]. Other cereals, such as wheat, rye, oat, triticale, sorghum, maize and so on, can also be used as raw material for beer production ^[3], as long as it is awared that this procedure may affect the sensory properties of the final beer. It is true that the usage of other cereals may confer beer with new properties and organoleptic features. However, at the same time, the incorporation of new cereals that do not contain the necessary enzymes may involve certain technological issues related to mash lautering, beer filtration, extract recovery, or production forecasting and scaling ^[4]. As an example, let us mention wheat beer, which is especially consumed in Bavaria and Austria and is characterized by clove-like, banana-like, vanilla, and fresh fruit scents ^[5]^[6]. Sorghum beers are described as one of the most subtle beers with regard to their sensory properties and mild taste ^[7]. Another study where different proportions of sorghum were used concluded that these beers have a lower acetaldehyde and ester content, and a greater proportion of higher alcohols ^[8]. The same authors described the beers that contained between 30 and 40% oat as better beverages in terms of aroma and taste purity than 100% malted barley beers, which contain lower amounts of lactones and higher alcohols, and a greater proportion of esters ^[9]. Other studies have concluded that different unmalted cereal adjuncts can replace malted barley at rates of up to 40–60% to produce beers with a sensory profile comparable to that of 100% malted barley beers ^[10]^[11].

Different barley genotypes lead to different chemical compositions, i.e., different enzymes and metabolites and, therefore, unequal results are expected from similar malting procedures ^[12]^[13]. Beers with higher fruity, floral, and grassy flavors are produced from Golden Promise barley—a classic British spring barley variety with a light malty flavor and beautiful mouthfeel—whereas other beers that are rich in toffee and toasted flavors, while exhibiting lower harshness or astringency, are obtained from Full Pint barley ^[14]. In this sense, CDC Copeland barley, a two-rowed malting barley, produces neutral flavors and pale colored beers. It has also been reported that, depending on the “terroir” where barley is grown, beers with different flavors can also be obtained ^[15].

The quality of the barley grain used as raw material is, therefore, another very important factor and it largely depends on agronomic practices, as well as on genetic and environmental variables ^[16]. Moreover, grain is required to present the adequate plumpness and kernel weight, with a high germination potential (≥95%) and the appropriate protein content. In this regard, barley’s protein content should be below 11%, otherwise the proteins that are soluble in wort may confer off-flavors to the final product. Moreover, high protein concentrations traditionally correlate with low carbohydrate levels and lower extract yields. The quality of barley may also be altered by microbial infections, being fungi the most commonly found microorganisms. These can infect barley while in the fields, especially during its wet growing season, while it may infect barley or malt while in storage under moist conditions. Primary gushing is associated with the use of defective malted barley, when harvested under wet conditions, while secondary gushing may be caused by solid particles, which may arise from various sources (dust polluted containers, faulty filtration, haze particles developing in aged beer, etc.), or adsorbed gas residues acting as nuclei for bubble formation. ^[17].

Malt contamination with Aspergillus fumigatus has been proven to be responsible for a noticeable rancid taste of beer ^[18]. Fungi growth on malt also has a negative effect on beer foam quality, because of the β-glucanases and xylanases produced that decrease the viscosity of the wort ^[19]. These and other negative aspects of the fungi that may grow on barley represent a hazard for the organoleptic properties of beer that may lead to consumers’ rejection ^[20]. Barley is also the vehicle for a variety of contaminating microorganisms other than fungi or molds and that may negatively affect the germination of barley prior to malting. Clostridium and Bacillus bacteria, which are generally associated with the production of butyric acid and sulfides, are amongst these other polluting organisms ^[21]. An excessive moisture level after completing the kilning or malting roasting process should be avoided if certain barley pollutants are to be prevented. In other words, proper storage and preservation procedures for the barley and the malted barley are crucial factors ^[19].

Barley is subjected to malting in order to solubilize the proteins and to break down the starch into fermentable sugars. Specific malting procedures also provide beer with characteristic colors and flavors ^[22]. During the malting process, the grains undergo chemical and structural changes that result in the generation of a number of precursors that will determine the organoleptic properties of the final beer, including its color, aroma, and flavor ^[23].

The malting process usually involves steeping, germination, and kilning. During the steeping process, cold water (10–15 °C) and oxygen are supplied into hygienic and calibrated kernels in order to maintain moisture levels at approximately 38–45% and promote the germination of the grains. At this stage, the grains’ endosperm cell walls and its proteins are broken through the action of certain enzymes, such as protease, amylase, or β-glucanase ^[24]^[25]. Different aspect of this process can be improved in several ways, as follows: using standardized seeds to achieve a uniform germination; using plump kernels to achieve maximum malt extract yields; and low protein content to attain higher extract levels and to enhance beer stability ^[26]. The quality of the malting process can be evaluated through ‘fine-grind’, which allows measurement of the soluble malt material, including fermentable sugars ^[27]. Other quality parameters used to evaluate the quality of the malting are kernel size fraction, kernel weight, protein contents, β-glucan, α-amylase activity, viscosity, and soluble nitrogen ratio ^[28].

Germination is ended by drying the grains (moisture content down to 3–4%) through a gradual increment of the temperature from 50 to roughly 85 °C or more (kilning). The kilning process has a crucial impact on beer color and flavor ^[25], mainly as a result of Maillard reaction, which produces maltoxazine, maltol, isomaltol, and ethyl maltol, among other substances responsible for the caramel, bread, or cotton candy-like flavors in beer ^[29]. Therefore, through the control of the temperature, Maillard reaction can be adjusted to determine color formation and obtain different types of malt (base, caramel, special, amber, chocolate, or black) ^[2], which will result in variations of the compounds responsible for wort flavor and for the different organoleptic profiles of the final beers ^[13]^[30]. It should also be noted that the melanoidins generated through Maillard reactions may promote the growth of certain undesirable microorganisms. In fact, melanoidins have been used as antimicrobial agents against different pathogenic bacteria strains ^[31]. Apart from melanoidins, certain malt alkaloids, mainly hordatines, have also been proven to have an influence on beer flavor by increasing its astringency ^[32]^[33].

2. Mashing and Wort

Mashing is an enzymatic process that produces sugars from malt to obtain wort, which is in turn fermented to produce beer. During this stage, the amylases, β-glucanases, and proteases degrade carbohydrates, β-glucans, and proteins, respectively. Their activities are affected by the temperature, pH, and composition of the solution, as well as by the processing time ^[34]. The action of these enzymes results in a final beer that contains a small amount of residual fermentable sugars (maltose being the most abundant one), a variable amount of dextrins, such as maltodextrin, and a small amount of peptides, which have an influence on the sensory properties and the palate fullness of the final beer.

Water is one of the most important ingredients during this mashing stage, because it represents most of the beer’s composition. The chemical composition of water, as well as the presence of pathogenic and/or non-pathogenic microorganisms, also has a considerable influence on the final result, so that it may even spoil beer to the point of rendering it unsuitable for human consumption ^[35].

The mineral composition of wort and beer, where the principal cations, such as calcium, magnesium, sodium, and potassium, as well as anions, such as sulfate, nitrate, phosphate, chlorides, and silicate, may also determine beer quality. The minor ions are iron, copper, zinc, and manganese ^[36]. Ions are necessary for the correct course of the fermentation process and for the growth of beneficial microorganisms ^[37], but also contribute directly to the flavor of beers as non-volatile taste-active compounds ^[38]. The mineral composition of the wort also depends on the nature of the raw materials ^[39]. Therefore, this factor must be taken into consideration when using cereals other tan malt.

As an example, Briggs et al. ^[2] established that the presence of calcium ions in the water used to make beer had a relevant influence on the mashing process and affected final beer flavor. According to Montanari et al. ^[36], calcium has the capacity to extract fine bittering principles from the hops and to reduce wort color, while sodium contributes to the perceived flavor of the beer by enhancing its sweetness. Other authors ^[40] have observed that “hard water” (with a high concentrations of salts; pH 8.47 ± 0.08) seemed to be a better extractor of the total carbohydrate content and B vitamins (riboflavin and niacin) than soft water (with a low concentrations of dissolved salts; pH 7.68 ± 0.23), whereas organic acid and iso-α-acid concentrations were not influenced by water pH values. It is a fact that the composition of wort has a great influence on the molecules that result from the fermentation process and, consequently, on the organoleptic profile of final beers. Therefore, as an example, wort sugar content levels and free amino nitrogen and lipids, as well as aeration ^[41] or temperature ^[42], are parameters that condition the subsequent production of aromatic esters by the microbiota ^[43]^[44]. Sucrose, fructose, glucose, maltose, maltotriose, and some dextrins, with maltose and maltotriose as the most abundant ones, are the main sugars that can be found in wort. Their concentrations depend on the characteristics of the barley and on the malting process ^[45].

Wort is also moderately rich in amino acids, peptides, and proteins ^[35]. Some amino acids are required for the healthy growing of yeast. Such amino acids, together with certain small peptides, constitute what is known as Free Amino Nitrogen (FAN). Total FAN is important for the fermentation (via yeast nutrition) and the stability of flavor. A high FAN content may affect beer flavor stability because of the production of vicinal diketones (VDK) such as diacetyl and 2,3-pentanedione, through the differential utilization of amino acids (valine and isoleucine, respectively) by yeast, which may provide beer with a butter- or butterscotch-like flavor or toffee-like flavor, respectively ^[46].

The releasing of free amino nitrogen and reducing sugars during the mashing stage contributes to a minor set of flavor precursors that can develop during the Maillard reaction, principally during wort boiling ^[47]. They are transformed during the mashing stage and through the metabolism of the yeasts during the fermentation stage into other new substances that contribute to the organoleptic profile of beer ^[48]^[49].

During mashing, a key cascade reaction is also initiated, where the products from lipid oxidation generate hydroperoxides that form active volatile compounds ^[47].

On the other hand, during this stage, unmalted adjuncts such as rice, wheat, corn, honey, or fruit can be added as an alternative cost-efficient source of extract that enables the production of innovative products that increase the content of bioactive compounds and generate unique flavors and bitterness and improve mouthfeel ^[50]^[51]^[52]. It has been observed that when rice is used in the brewing process, it provides neutral, clean, and dry sensory characteristics, whereas adding corn results in a fuller mouthfeel ^[53].

More sour, grainy, and sweet corn aroma beers were obtained when 60% torrefied maize was added to the wort ^[11]. The addition of unmalted barley at up to 50% resulted in beers with a preference rating that was comparable, with regard to odor and taste, to that of all-malt beers ^[54]. In contrast, when the added unmalted barley reached 90%, it resulted in more astringent beers, while 100% unmalted barley produced final beers with less body and mouthfeel ^[55].

Certain extracts from medicinal plants can also be added to the wort in order to produce beers with unique sensory characteristics and an increased concentration of various bioactive compounds, such as phenols ^[56].

3. Hops

Resins and essential oils can be found in the lupulin glands of female hop flowers, which, even when used in small amounts, contribute to bitterness and aroma (sensorially characterized by descriptors such as ‘fruity’, ‘floral’, ‘spicy’, ‘herbal’, or ‘woody’) ^[57]^[58]. In fact, hops are the main ingredient responsible for the bitterness of beer because of their polyphenols and α-acids contributions ^[59]^[60]^[61]. Hops contain a complex mixture of volatile compounds (essential oils), among which linalool, geraniol, and 4-methyl-4-sulfanylpentan-2-one are of particular importance ^[62].

Hop varieties can be classified as aroma hops, dual-purpose hops (aromatic and bitter), and bittering hops (very bitter) ^[63]. Saaz and the rest of the “noble hops”—Hallertauer Mittelfrüh, Tettnang, and Spalt—belong to the first category and are traditionally used for pilsners and lagers produced in the Bavaria and Bohemia regions. Another Saaz aroma hop, Styrian Goldings, is often preferred for Belgian-style ales. Bitter (high α-acid) or dual-purpose hops such as Citra, Centennial, Cascade, or Amarillo, among others, are typically used for American IPAs ^[64].

During wort boiling, the humulones (α-acids) that are found in the soft resins of hops are isomerized into isohumulones, which are the main components responsible for the bitterness of beer ^[65]. It has also been recently observed that the oxidized forms of humulones, humulinones that are present in dry-hopped and hop-forward beers, can also contribute to beer bitterness ^[66].

During wort boiling, the majority of the volatiles derived from hops are lost through evaporation. Thus, by the late addition of multiple dosages, beers could be obtained with hop aroma but without any extra hop bitterness. So, for a less bitter beer, hops can be added toward the end of the wort boiling stage, or to the whirlpool (late hopping) or to green and bright beer (dry-hopping) ^[67]. The flavor descriptors that are most often detected in late hopped beers are spicy, noble, herbal, woody, and, to a lesser extent, estery or fruity. Dry-hopping consists of the cold extraction of volatile and non-volatile hop compounds. This technique is widely employed by brewers to increase the aroma and stability of beer flavor ^[68]. The descriptors that are most frequently found in dry-hopped beers are floral, citrus, or pine ^[69]^[70]. Unlike in boiling hopping, dry-hopping does not allow for the thermal isomerization of the α-acids into iso-α-acids, which makes beer more prone to microbial instability ^[71]. Recent investigations on the microbial contamination hazards associated with dry-hopping techniques have detected spore-forming bacteria such as Bacillus spp., as well as Enterobacteriaceae, yeast, and fungi ^[72].

There is also evidence that the amylolytic enzymes present in hops can biochemically modify dry-hopping beer, which may lead to the degradation of long-chain, unfermentable dextrins into fermentable sugars ^[73]. This increase in fermentable sugars can, in the presence of yeast, give rise to a slow secondary fermentation, which is referred to as “hop creep” ^[74]. “Hop creep” represents a problem for brewers, because it modifies the specific density, flavor profile, and alcohol content of beers. Bruner et al. ^[75] revealed that hop creep resulted in 1.06% (v/v) alcohol increments in dry-hopped lager beers and 0.88% (v/v) in ale ones, over 30 day periods.

Beer aroma can also be modified by adding pure aroma hop extract ^[76]. Moreover, the addition of hop extracts to unhoped beer has been demonstrated to improve mouthfeel and fullness while increasing the bitter perception of beer ^[77]. Hop extracts are also commonly added for extra bitterness and to obtain a greater content of aromatic compounds from the different stages of the brewing process ^[78].

4. Maturation, Storage, and Bottling

Beer is an unstable product whose composition can change during storage and bottling ^[13] through different types of reaction.

During the maturation phase, some off-flavor compounds from previous stages may reduce their concentrations and facilitate the production of a more balanced product. The bitterness provided by the hops and by some polyphenols such as gallic acid, flavonoids, and tannins, is also dependent on the specific conditions under which this phase takes place. Generally, during maturation, bitterness decreases and sweetness increases. Nevertheless, the extent to which this phenomenon occurs depends on a number of factors, including the type of beer ^[59]. In the case of lager beers, certain aromatic changes may take place during storage, together with a linear decrease in bitterness, because of the degradation of isohumulones and/or humulinones, and an increment of sweet aroma, toffee flavor, cardboard taint, and ribes off-flavor ^[79]^[80].

Certain compounds such as the furfural extracted from wood, and the esters generated by the esterification reactions that take place between alcohols—mainly ethanol and acids—during beer aging in wood change their concentrations, which increases beer bitterness as greater amounts of tannins are extracted from the wood ^[59]. Another aspect that should be considered during this particular maturation is that different microorganisms can contribute with different compounds to beer, but their presence will depend on the state and type of wood used for the aging ^[81]. For example, lambic beer matures in wooden casks, and yeasts such as Brettanomyces bruxellensis, Brettanomyces anomalous, and Pichia membranifaciens; acetic acid bacteria; and the LAB Pediococcus damnosus and Lactobacillus brevis, among others, play an important role in the process because they contribute to the typical Brett flavor of lambic beer, characterized by spicy and medicinal notes, and also fruity and floral ones. Thus, the ester-synthesizing activity of Brettanomyces contributes to the production of various ethyl esters, such as ethyl caproate or ethyl caprylate, that contribute to floral notes, at concentrations significantly higher than those found in other beers. In addition, the Brettanomyces yeast species that contain a superoxide dismutase enzyme with vinyl phenol reductase activity can form 4-ethylphenol and 4-ethylguaiacol, which are responsible for spicy and medicinal notes. Brettanomyces can also produce isovaleric acid from leucine, and this acid is responsible for sweaty and cheesy flavors, and may also produce mousy off-flavors that are associated with 2-ethyltetrahydropyridine and 2-acetyltetrahydropyridine. The presence of acetic acid and lactic acid bacteria also contributes to the high concentrations of ethyl acetate and ethyl lactate. In addition, acetoin, which is produced by AAB species through the utilization of lactate, may contribute to undesirable buttery notes ^[82]^[83].

It is also known that, after bottling, beer flavor is affected by certain chemical reactions that lead to instability, being an indicator of the increment of sensory-active aldehydes, which are generated in the sequence of radical reactions initiated by reactive oxygen species ^[84]^[85]. These aldehydes are also produced during mashing and wort boiling, but they decrease during the fermentation stage. It has been demonstrated that hop polyphenols slow down the sensory deterioration of pale lager beer as they suppress the formation of sensory-active aldehydes.

A traditional method to achieve beer carbonation consists of bottle re-fermentation, which is initiated by adding yeast and fermentable carbohydrates. As a result of yeast multiplication, carbonation increases and the concentration of flavor-active compounds is also affected, so that beer aroma and taste are also modified ^[86]. New flavors are produced as a result of the yeast activity, which incorporates higher alcohols, esters, aldehydes, vicinal diketones, and sulfur compounds that have an influence on beer aroma ^[48]. So, there are certain yeast strains that produce phenolic flavors resembling clove, smoked meat, or medicinal odors, among others ^[87]. Furthermore, the increment of carbon dioxide concentrations enhances beer effervescence. An additional effect of bottling is the prevention of oxidative damage, as yeast consumes oxygen.

Another factor to take into account is the presence of contaminants from previous stages that may reach the beer storage phase.

References

Briggs, D. Malts and Malting; Springer Science & Business Media: Berlin/Heidelberg, Germany, 1998.
Briggs, D.E.; Boulton, C.A.; Brookes, P.A.; Stevens, R. Brewing: Science and Practice; CRC Press: Cambridge, UK, 2004.
Gąsior, J.; Kawa-Rygielska, J.; Kucharska, A. Carbohydrates profile, polyphenols content and antioxidative properties of beer worts produced with different dark malts varieties or roasted barley grains. Molecules 2020, 25, 3882.
Phiarais, B.P.N.; Mauch, A.; Schehl, B.D.; Zarnkow, M.; Gastl, M.; Herrmann, M.; Zannini, E.; Arendt, E.K. Processing of a Top Fermented Beer Brewed from 100% Buckwheat Malt with Sensory and Analytical Characterisation. J. Inst. Brew. 2010, 116, 265–274.
Langos, D.; Granvogl, M.; Schieberle, P. Characterization of the key aroma compounds in two Bavarian wheat beers by means of the sensomics approach. J. Agric. Food Chem. 2013, 61, 11303–11311.
Yin, H.; Dong, J.; Yu, J.; Chang, Z.; Qian, Z.; Liu, M.; Huang, S.; Hu, X.; Liu, X.; Deng, Y.; et al. A preliminary study about the influence of high hydrostatic pressure processing on the physicochemical and sensorial properties of a cloudy wheat beer. J. Inst. Brew. 2016, 122, 462–467.
Coulibaly, W.H.; Florent N’guessan, K.; Coulibaly, I.; Cot, M.; Rigou, P.; Djè, K.M. Influence of Freeze-Dried Yeast Starter Cultures on Volatile Compounds of Tchapalo, a Traditional Sorghum Beer from Côte d’Ivoire. Beverages 2016, 2, 35.
Schnitzenbaumer, B.; Karl, C.A.; Jacob, F.; Arendt, E.K. Impact of Unmalted White Nigerian and Red Italian Sorghum (Sorghum bicolor) on the Quality of Worts and Beers Applying Optimized Enzyme Levels. J. Am. Soc. Brew. Chem. 2013, 71, 258–266.
Schnitzenbaumer, B.; Kerpes, R.; Titze, J.; Jacob, F.; Arendt, E.K. Impact of Various Levels of Unmalted Oats (Avena sativa L.) on the Quality and Processability of Mashes, Worts, and Beers. J. Am. Soc. Brew. Chem. 2012, 70, 142–149.
Deng, Y.; Lim, J.; Lee, G.H.; Hanh Nguyen, T.T.; Xiao, Y.; Piao, M.; Kim, D. Brewing rutin-enriched lager beer with buckwheat malt as adjuncts. J. Microbiol. Biotechnol. 2019, 29, 877–886.
Yorke, J.; Cook, D.; Ford, R. Brewing with Unmalted Cereal Adjuncts: Sensory and Analytical Impacts on Beer Quality. Beverages 2021, 7, 4.
Bettenhausen, H.M.; Benson, A.; Fisk, S.; Herb, D.; Hernandez, J.; Lim, J.; Queisser, S.H.; Shellhammer, T.H.; Vega, V.; Yao, L.; et al. Variation in Sensory Attributes and Volatile Compounds in Beers Brewed from Genetically Distinct Malts: An Integrated Sensory and Non-Targeted Metabolomics Approach. J. Am. Soc. Brew. Chem. 2020, 78, 136–152.
Bettenhausen, H.M.; Barr, L.; Broeckling, C.D.; Chaparro, J.M.; Holbrook, C.; Sedin, D.; Heuberger, A.L. Influence of malt source on beer chemistry, flavor, and flavor stability. Food Res. Int. 2018, 113, 487–504.
Herb, D.; Filichkin, T.; Fisk, S.; Helgerson, L.; Hayes, P.; Meints, B.; Jennings, R.; Monsour, R.; Tynan, S.; Vinkemeier, K.; et al. Effects of barley (Hordeum vulgare L.) variety and growing environment on beer flavor. J. Am. Soc. Brew. Chem. 2017, 75, 345–353.
Kyraleou, M.; Herb, D.; O’reilly, G.; Conway, N.; Bryan, T.; Kilcawley, K.N. The impact of terroir on the flavour of single malt whisk(E)y new make spirit. Foods 2021, 10, 443.
McMillan, T.; Tidemann, B.D.; O’Donovan, J.T.; Izydorczyk, M.S. Effects of plant growth regulator application on the malting quality of barley. J. Sci. Food Agric. 2020, 100, 2082–2089.
Casey, G.P. Primary Versus Secondary Gushing and Assay Procedures Used to Assess Malt/Beer Gushing Potential. MBAA Tech. Q. 1996, 33, 229–235.
Kyselová, L.; Brányik, T. Quality Improvement and Fermentation Control in Beer; Elsevier Ltd.: Amsterdam, The Netherlands, 2015; ISBN 9781782420248.
Bokulich, N.A.; Bamforth, C.W. The Microbiology of Malting and Brewing. Microbiol. Mol. Biol. Rev. 2013, 77, 157–172.
Hill, A.E. Microbiological stability of beer. In Handbook of Alcoholic Beverages: Beer, a Quality Perspective; Bamforth, C.W., Russell, I., Stewart, G., Eds.; Academic Press: Cambridge, MA, USA; Elsevier: New York, NY, USA, 2009; pp. 163–183. ISBN 9780126692013.
Back, W. Color atlas and handbook of beverage biology. In Color Atlas and Handbook of Beverage Biology; Fachverlag Hans Carl: Numberg, Germany, 2005.
Gupta, M.; Abu-Ghannam, N.; Gallaghar, E. Barley for brewing: Characteristic changes during malting, brewing and applications of its by-products. Compr. Rev. Food Sci. Food Saf. 2010, 9, 318–328.
Chandra, G.S.; Proudlove, M.O.; Baxter, E.D. The structure of barley endosperm—An important determinant of malt modification. J. Sci. Food Agric. 1999, 79, 37–46.
Iimure, T.; Sato, K. Beer proteomics analysis for beer quality control and malting barley breeding. Food Res. Int. 2013, 54, 1013–1020.
Justé, A.; Malfliet, S.; Lenaerts, M.; De Cooman, L.; Aerts, G.; Willems, K.A.; Lievens, B. Microflora during malting of barley: Overview and impact on malt quality. Brew. Sci. 2011, 64, 22–31.
Mather, D.E.; Tinker, N.A.; LaBerge, D.E.; Edney, M.; Jones, B.L.; Rossnagel, B.G.; Legge, W.G.; Briggs, K.G.; Irvine, R.B.; Falk, D.E.; et al. Regions of the genome that affect grain and malt quality in a North American two-row Barley Cross. Crop Sci. 1997, 37, 544–554.
Heuberger, A.L.; Broeckling, C.D.; Kirkpatrick, K.R.; Prenni, J.E. Application of nontargeted metabolite profiling to discover novel markers of quality traits in an advanced population of malting barley. Plant Biotechnol. J. 2014, 12, 147–160.
Fox, G.P.; Panozzo, J.F.; Li, C.D.; Lance, R.C.M.; Inkerman, P.A.; Henry, R.J. Molecular basis of barley quality. Aust. J. Agric. Res. 2003, 54, 1081–1101.
Coghe, S.; Martens, E.; D’Hollander, H.; Dirinck, P.J.; Delvaux, F.R. Sensory and Instrumental Flavour Analysis of Wort Brewed with Dark Specialty Malts. J. Inst. Brew. 2004, 110, 94–103.
Dack, R.E.; Black, G.W.; Koutsidis, G.; Usher, S.J. The effect of Maillard reaction products and yeast strain on the synthesis of key higher alcohols and esters in beer fermentations. Food Chem. 2017, 232, 595–601.
Rufián-Henares, J.A.; Morales, F.J. Antimicrobial activity of melanoidins. J. Food Qual. 2007, 30, 160–168.
Inui, T.; Tsuchiya, F.; Ishimaru, M.; Oka, K.; Komura, H. Different Beers with Different Hops. Relevant Compounds for Their Aroma Characteristics. J. Agric. Food Chem. 2013, 61, 4758–4764.
Kageyama, N.; Inui, T.; Fukami, H.; Komura, H. The science of beer elucidation of chemical structures of components responsible for beer aftertaste. J. Am. Soc. Brew. Chem. 2018, 69, 255–259.
Rübsam, H.; Gastl, M.; Becker, T. Determination of the influence of starch sources and mashing procedures on the range of the molecular weight distribution of beer using field-flow fractionation. J. Inst. Brew. 2013, 119, 139–148.
Anderson, H.E.; Santos, I.C.; Hildenbrand, Z.L.; Schug, K.A. A review of the analytical methods used for beer ingredient and finished product analysis and quality control. Anal. Chim. Acta 2019, 1085, 1–20.
Montanari, L.; Mayer, H.; Marconi, O.; Fantozzi, P. Minerals in Beer. In Beer in Health and Disease Prevention; Elsevier: Amsterdam, The Netherlands, 2009; pp. 359–365.
Sterczyńska, M.; Stachnik, M.; Poreda, A.; Pużyńska, K.; Piepiórka-Stepuk, J.; Fiutak, G.; Jakubowski, M. Ionic composition of beer worts produced with selected unmalted grains. LWT 2021, 137, 110348.
Schoenberger, C.; Krottenthaler, M.; Back, W. Sensory and Analytical Characterization of Nonvolatile Taste-Active Compounds in Bottom-Fermented Beers. MBAA Tech. Q. 2002, 39, 210–217.
Poreda, A.; Bijak, M.; Zdaniewicz, M.; Jakubowski, M.; Makarewicz, M. Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products. J. Inst. Brew. 2015, 121, 224–230.
Punčochářová, L.; Pořízka, J.; Diviš, P.; Štursa, V. Study of the influence of brewing water on selected analytes in beer. Potravin. Slovak J. Food Sci. 2019, 13, 507–514.
Webersinke, F.; Klein, H.; Flieher, M.; Urban, A.; Jäger, H.; Forster, C. Control of Fermentation By-Products and Aroma Features of Beer Produced with Scottish Ale Yeast by Variation of Fermentation Temperature and Wort Aeration Rate. J. Am. Soc. Brew. Chem. 2018, 76, 147–155.
Kucharczyk, K.; Tuszyński, T. The effect of temperature on fermentation and beer volatiles at an industrial scale. J. Inst. Brew. 2018, 124, 230–235.
Verstrepen, K.J.; Derdelinckx, G.; Dufour, J.; Winderickx, J.; Thevelein, J.M.; Pretorius, I.S.; Delvaux, F.R.; Box, P.O.; Osmond, G.; Sa, A. Flavor active esters adding fruitiness to beer. J. Biosci. Bioeng. 2003, 96, 110–118.
Loviso, C.L.; Libkind, D. Synthesis and regulation of flavor compounds derived from brewing yeast: Esters. Rev. Argent. Microbiol. 2018, 50, 436–446.
He, Y.; Dong, J.; Yin, H.; Zhao, Y.; Chen, R.; Wan, X.; Chen, P.; Hou, X.; Liu, J.; Chen, L. Wort composition and its impact on the flavour-active higher alcohol and ester formation of beer—A review. J. Inst. Brew. 2014, 120, 157–163.
Krogerus, K.; Gibson, B.R. 25 th Anniversary Review: Diacetyl and its control during brewery fermentation. J. Inst. Brew. 2013, 119, 86–97.
Hughes, P. Beer flavor. In Beer, A quality Perspective. Handbook of Alcoholic Beverages; Academic Press: Cambridge, MA, USA; Elsevier: Amsterdam, The Netherlands, 2009; pp. 61–83.
Pires, E.J.; Teixeira, J.A.; Brányik, T.; Vicente, A.A. Yeast: The soul of beer’s aroma—A review of flavour-active esters and higher alcohols produced by the brewing yeast. Appl. Microbiol. Biotechnol. 2014, 98, 1937–1949.
Ferreira, I.; Guido, L. Impact of Wort Amino Acids on Beer Flavour: A Review. Fermentation 2018, 4, 23.
Humia, B.V.; Santos, K.S.; Schneider, J.K.; Leal, I.L.; de Abreu Barreto, G.; Batista, T.; Machado, B.A.S.; Druzian, J.I.; Krause, L.C.; da Costa Mendonça, M.; et al. Physicochemical and sensory profile of Beauregard sweet potato beer. Food Chem. 2020, 312, 126087.
Kok, Y.J.; Ye, L.; Muller, J.; Ow, D.S.-W.; Bi, X. Brewing with malted barley or raw barley: What makes the difference in the processes? Appl. Microbiol. Biotechnol. 2019, 103, 1059–1067.
Mehra, R.; Kumar, H.; Kumar, N.; Kaushik, R. Red rice conjugated with barley and rhododendron extracts for new variant of beer. J. Food Sci. Technol. 2020, 57, 4152–4159.
Bogdan, P.; Kordialik-Bogacka, E. Alternatives to malt in brewing. Trends Food Sci. Technol. 2017, 65, 1–9.
Kunz, T.; Müller, C.; Mato-Gonzales, D.; Methner, F.-J. The influence of unmalted barley on the oxidative stability of wort and beer. J. Inst. Brew. 2012, 118, 32–39.
Steiner, E.; Auer, A.; Becker, T.; Gastl, M. Comparison of beer quality attributes between beers brewed with 100% barley malt and 100% barley raw material †. J. Sci. Food Agric. 2012, 92, 803–812.
Ducruet, J.; Rébénaque, P.; Diserens, S.; Kosińska-Cagnazzo, A.; Héritier, I.; Andlauer, W. Amber ale beer enriched with goji berries—The effect on bioactive compound content and sensorial properties. Food Chem. 2017, 226, 109–118.
Baiano, A. Craft beer: An overview. Compr. Rev. Food Sci. Food Saf. 2020, 20, 1829–1856.
De Keukeleire, D. Fundamentals of beer and hop chemistry. Quim. Nova 2000, 23, 108–112.
Luo, Y.; Kong, L.; Xue, R.; Wang, W.; Xia, X. Bitterness in alcoholic beverages: The profiles of perception, constituents, and contributors. Trends Food Sci. Technol. 2020, 96, 222–232.
Oladokun, O.; Tarrega, A.; James, S.; Cowley, T.; Dehrmann, F.; Smart, K.; Cook, D.; Hort, J. Modification of perceived beer bitterness intensity, character and temporal profile by hop aroma extract. Food Res. Int. 2016, 86, 104–111.
Oladokun, O.; Tarrega, A.; James, S.; Smart, K.; Hort, J.; Cook, D.; Lafontaine, S.R.; Shellhammer, T.H.; Ceola, D.; Huelsmann, R.D.; et al. The impact of hop bitter acid and polyphenol profiles on the perceived bitterness of beer. Food Chem. 2016, 205, 212–220.
Almaguer, C.; Schönberger, C.; Gastl, M.; Arendt, E.K.; Becker, T. Humulus lupulus—A story that begs to be told. A review. J. Inst. Brew. 2014, 120, 289–314.
Krofta, K. Comparison of quality parameters of Czech and foreign hop varieties. Plant Soil Environ. 2003, 49, 261–268.
Buarque, B.S.; Davies, R.B.; Hynes, R.M.; Kogler, D.F. Hops, Skip & a Jump: The Regional Uniqueness of Beer Styles; UCD Centre for Economic Research Working Paper Series; WP2020/31; Geary Institute; University College Dublin: Dublin, Ireland, 2020.
Verzele, M.; De Keukeleire, D. Chemistry and Analysis of Hop and Beer Bitter Acids. In Developments in Food Science; Verzele, M., De Keukeleire, D., Eds.; Elsevier: Amsterdam, The Netherlands, 1991; Volume 27, ISBN 0444881654.
Hahn, C.D.; Lafontaine, S.R.; Pereira, C.B.; Shellhammer, T.H. Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers. J. Agric. Food Chem. 2018, 66, 3505–3513.
Rettberg, N.; Biendl, M.; Garbe, L.A. Hop aroma and hoppy beer flavor: Chemical backgrounds and analytical tools—A review. J. Am. Soc. Brew. Chem. 2018, 76, 1–20.
Lafontaine, S.R.; Shellhammer, T.H. Investigating the Factors Impacting Aroma, Flavor, and Stability in Dry-Hopped Beers. MBAA Tech. Q. 2019, 56, 13–23.
Eyres, G.T.; Dufour, J.P. Hop Essential Oil: Analysis, Chemical Composition and Odor Characteristics. In Beer in Health and Disease Prevention; Academic Press: Cambridge, MA, USA; Elsevier: Amsterdam, The Netherlands, 2009; pp. 239–254.
Castro, R.; Díaz, A.B.; Durán-Guerrero, E.; Lasanta, C. Influence of different fermentation conditions on the analytical and sensory properties of craft beers: Hopping, fermentation temperature and yeast strain. J. Food Compos. Anal. 2022, 106, 104278.
Caballero, I.; Blanco, C.A.; Porras, M. Iso-α-acids, bitterness and loss of beer quality during storage. Trends Food Sci. Technol. 2012, 26, 21–30.
Jelínek, L.; Müllerova, J.; Karavín, M.; Dostalek, P. The secret of dry hopped beers—Review. Kvas. Prum. 2018, 64, 287–296.
Kirkpatrick, K.R.; Shellhammer, T.H. A Cultivar-Based Screening of Hops for Dextrin Degrading Enzymatic Potential. J. Am. Soc. Brew. Chem. 2018, 76, 247–256.
Stokholm, A.; Shellhammer, T.H. Hop Creep–Technical Brief; Brewers Association: Boulder, CO, USA, 2020.
Bruner, J.; Williams, J.; Fox, G. Further Exploration of Hop Creep Variability with Humulus lupulus Cultivars and Proposed Method for Determination of Secondary Fermentation. MBAA Tech. Q. 2020, 57, 169–176.
Oladokun, O.; James, S.; Cowley, T.; Dehrmann, F.; Smart, K.; Hort, J.; Cook, D. Perceived bitterness character of beer in relation to hop variety and the impact of hop aroma. Food Chem. 2017, 230, 215–224.
Van Opstaele, F.; Goiris, K.; De Rouck, G.; Aerts, G.; De Cooman, L. Production of novel varietal hop aromas by supercritical fluid extraction of hop pellets—Part 2: Preparation of single variety floral, citrus, and spicy hop oil essences by density programmed supercritical fluid extraction. J. Supercrit. Fluids 2012, 71, 147–161.
Sanz, V.; Torres, M.D.; López Vilariño, J.M.; Domínguez, H. What is new on the hop extraction? Trends Food Sci. Technol. 2019, 93, 12–22.
Lermusieau, G.; Noël, S.; Liégeois, C.; Collin, S. Nonoxidative mechanism for development of trans-2-nonenal in beer. J. Am. Soc. Brew. Chem. 1999, 57, 29–33.
Ferreira, C.S.; Bodart, E.; Collin, S. Why craft brewers should be advised to use bottle refermentation to improve late-hopped beer stability. Beverages 2019, 5, 39.
Spedding, G.; Aiken, T. Sensory analysis as a tool for beer quality assessment with an emphasis on its use for microbial control in the brewery. In Brewing Microbiology. Managing Microbes, Ensuring Quality and Valorising Waste; Elsevier: Amsterdam, The Netherlands, 2015; pp. 375–404.
Bongaerts, D.; De Roos, J.; De Vuyst, L. Technological and Environmental Features Determine the Uniqueness of the Lambic Beer Microbiota and Production Process. Appl. Environ. Microbiol. 2021, 87, e00612-21.
De Roos, J.; Verce, M.; Weckx, S.; De Vuyst, L. Temporal Shotgun Metagenomics Revealed the Potential Metabolic Capabilities of Specific Microorganisms during Lambic Beer Production. Front. Microbiol. 2020, 11, 1692.
Nobis, A.; Kwasnicki, M.; Lehnhardt, F.; Hellwig, M.; Henle, T.; Becker, T.; Gastl, M. A Comprehensive Evaluation of Flavor Instability of Beer (Part 2): The Influence of De Novo Formation of Aging Aldehydes. Foods 2021, 10, 2668.
Mikyška, A.; Jurková, M.; Horák, T.; Slabý, M. Study of the influence of hop polyphenols on the sensory stability of lager beer. Eur. Food Res. Technol. 2022, 248, 533–542.
Derdelinckx, G.; Neven, H.; Demeyer, I.; Delvaux, F. Belgian special beers: Refermented beers, white and wheat beers, amber and dark beers, spiced and hoppy beers. Belgian J. Brew. Biotechnol. 1995, 20, 67–73.
Štulíková, K.; Novák, J.; Vlček, J.; Šavel, J.; Košin, P.; Dostálek, P. Bottle Conditioning: Technology and Mechanisms Applied in Refermented Beers. Beverages 2020, 6, 56.

© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.

Upload a video for this entry

Information

Subjects: Biotechnology & Applied Microbiology

Contributors MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :

Ana Belén Díaz

Enrique Durán-Guerrero

Cristina Lasanta

Remedios Castro

View Times: 655

Update Date: 11 Nov 2022

Table of Contents

Video Upload Options

Confirm