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Correlations between the concentrations (mg/L) (a) ethyl octanoate and ethyl hexanoate, (b) ethyl hexanoate and hexanoic acid, and (c) ethyl octanoate and octanoic acid (in six fresh beers: A-F).
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The aromatic complexity of craft beers, together with some particular practices (use of small vessels, dry hopping, etc.), can cause more oxidation associated with pre-maturated colloidal instability, Madeira off-flavors, bitterness decrease, and aroma loss. As bottle refermentation is widely used in Belgian craft beers, the aim of the present work...
Citations
... Most notably, hybrids emerging from the Beer and Bioethanol lineages differentiated each other in the production of acetate esters and higher alcohols (fruity/flowery), fatty acids (waxy), and their derivative esters (flowery). Although waxy aromas are considered off-flavors in beer, octanoic and decanoic acids in our Bioethanol hybrids were detected within the range of commercial beverages (62,63). The volatile compound profile of S. cerevisiae Beer hybrids varied depending on the S. eubayanus parent, suggesting that the volatile compound machinery of S. eubayanus exhibits a dominant inheritance over that of the Beer S. cerevisiae strain in shaping these traits. ...
Hybridization between Saccharomyces cerevisiae and Saccharomyces eubayanus resulted in the emergence of S. pastorianus , a crucial yeast for lager fermentation. However, our understanding of hybridization success and hybrid vigor between these two species remains limited due to the scarcity of S. eubayanus parental strains. Here, we explore hybridization success and the impact of hybridization on fermentation performance and volatile compound profiles in newly formed lager hybrids. By selecting parental candidates spanning a diverse array of lineages from both species, we reveal that the Beer and PB-2 lineages exhibit high rates of hybridization success in S. cerevisiae and S. eubayanus , respectively. Polyploid hybrids were generated through a spontaneous diploid hybridization technique (rare-mating), revealing a prevalence of triploids and diploids over tetraploids. Despite the absence of heterosis in fermentative capacity, hybrids displayed phenotypic variability, notably influenced by maltotriose consumption. Interestingly, ploidy levels did not significantly correlate with fermentative capacity, although triploids exhibited greater phenotypic variability. The S. cerevisiae parental lineages primarily influenced volatile compound profiles, with significant differences in aroma production. Interestingly, hybrids emerging from the Beer S. cerevisiae parental lineages exhibited a volatile compound profile resembling the corresponding S. eubayanus parent. This pattern may result from the dominant inheritance of the S. eubayanus aroma profile, as suggested by the over-expression of genes related to alcohol metabolism and acetate synthesis in hybrids including the Beer S. cerevisiae lineage. Our findings suggest complex interactions between parental lineages and hybridization outcomes, highlighting the potential for creating yeasts with distinct brewing traits through hybridization strategies.
IMPORTANCE
Our study investigates the principles of lager yeast hybridization between Saccharomyces cerevisiae and Saccharomyces eubayanus . This process gave rise to the lager yeast Saccharomyces pastorianus . By examining how these novel hybrids perform during fermentation and the aromas they produce, we uncover the genetic bases of brewing trait inheritance. We successfully generated polyploid hybrids using diverse strains and lineages from both parent species, predominantly triploids and diploids. Although these hybrids did not show improved fermentation capacity, they exhibited varied traits, especially in utilizing maltotriose, a key sugar in brewing. Remarkably, the aroma profiles of these hybrids were primarily influenced by the S. cerevisiae parent, with Beer lineage hybrids adopting aroma characteristics from their S. eubayanus parent. These insights reveal the complex genetic interactions in hybrid yeasts, opening new possibilities for crafting unique brewing yeasts with desirable traits.
... In addition, these compounds can limit flavour deterioration by inhibiting the formation of stalling compounds, and increasing beer antioxidant activity (Yang et al., 2017;Zhao et al., 2016) A refermentation in bottlesa procedure which is often used to carbonate the beer in homebrewing, and sometimes in the craft industry, can prolong beverage stability (Štulíková et al., 2020). Ferreira et al. (2019) report that the use of bottle conditioning reduced the release of the trans-2nonenal from Schiff bases and resulted in the release of terpenols and phenols which positively affected the beers aroma. During the sensory evaluation, the intensity of attributes usually associated with beer ageing was judged to be absent or low (Ferreira et al., 2019). ...
... Ferreira et al. (2019) report that the use of bottle conditioning reduced the release of the trans-2nonenal from Schiff bases and resulted in the release of terpenols and phenols which positively affected the beers aroma. During the sensory evaluation, the intensity of attributes usually associated with beer ageing was judged to be absent or low (Ferreira et al., 2019). This is confirmed by the study by Saison et al. (2010), where the effect of refermentation on aged beer was studied; the yeast's have significant ability to reduce the compounds responsible for stale aroma. ...
Fermented beverages such as beer are known for their relatively long shelf life. However, the main factor limiting their shelf life is the qualitative changes that occur during storage. From the moment the beer is produced, its characteristics, such as taste, aroma, and colloidal stability undergo continuous change. The intensity of these changes depends on the type of beer, storage conditions, and length of storage. While some degree of ageing can have a positive influence on sensory characteristics of a beer, beer stalling is seen as a significant problem. As it is currently understood, beer ageing is mainly caused by the formation of stalling aldehydes. At the same time, compounds which bestow the beer its flavour, such as esters, terpenes, and iso-α-acids undergo qualitative and quantitative changes. As a result, aroma discriminants such as freshness, fruitiness or florality are often lost over time. In their place, aromas described as ribes, cardboard, bread-like, honey-like or sherry-like appear. The article aims to present the changes in beer sensorial, physicochemical, and microbiological characteristics during storage and the factors that affect beer quality during ageing The article also describes the variables which according to the current literature, may alter the flavour stability of a beer.
... In addition, the production of craft beer is linked to the constant exigency for innovation and research into better flavors, aromas, development of packaging design, and labeling [79,80]. This is why cooperation with local institutions such as universities, advisory services, and agricultural advisors [81] is extremely important for craft breweries. In this way, greater engagement of science and local policymakers is encouraged to improve the identity that craft beer forms. ...
... Finally, in recent years, the value that a certain locality addresses in the spheres of food science for craft breweries has been intensively studied. Many authors in their papers that investigate this issue emphasize the effect of the mentioned value on the environment and sustainability due to the existence of the growing practice of original forms of industrial symbiosis in which craft breweries cooperate with farmers in local hubs [78,81,95]. This form of cooperation enriches in a sustainable and efficient manner, networking ways to promote biological diversity and, more vital, ecological development. ...
Craft beer represents a dynamic and creative segment within the food and beverage industry, emphasizing quality, aroma, health, sustainability, locality, and tailored brewing techniques. This paper explores the multifaceted roles of craft beer’s production and consumption growth dynamics. Both a bibliometric analysis and a systematic literature review were conducted on a sample of 239 scientific papers to provide an in-depth evaluation of the main characteristics and influences that craft beer has in the field of food science. Based on the identified roles of craft beer/breweries in the selected sample of literature, a conceptual framework was constructed to serve as a guideline for policymakers and different stakeholders. In this way, our findings enrich the existing literature and contribute to a better understanding of craft beer production and surroundings, which can be beneficial for promoting sustainable policies and innovative strategies for the growth of small/micro-producers and entrepreneurs in this niche market. Furthermore, this evidence can stimulate clear and ethical information to enhance consumers’ knowledge and agendas to strengthen the identity of local communities.
... Conversely, condensation reactions can occur between ethanol and organic acids, with the formation of unpleasant ester molecules ( Vanderhaegen et al., 2006 ). During storage the concentrations of other carbonyl compounds tend to increase, such us -damascenone ( Ferreira et al., 2022 ;Silva Ferreira, Bodart & Collin, 2019 ) and -nonalactone ( Eichhorn, Komori, Miedaner & Narziss, 1989 ;Daan Saison et al., 2010 ), and they are considered as volatile markers of aged beers ( Gijs, Chevance, Jerkovic & Collin, 2002 ;Saison et al., 2009 ). ...
Beer oxidation is strictly linked to its shelf life. Chemical variation in aldehydes, higher alcohols, hops bitter substances and esters, also could have a role key in stale flavor. Bottle refermentation, is the method by which beer in the bottle is made sparkling and is often used in craft brewing. Before the process an amount of oxygen in the headspace can be a potential source of oxidation. We investigated the effect of oxygen and temperature during storage of refermented craft beer in bottles with standard and oxygen scavenger caps. Beer was stored for 13 weeks at 6, 22 and 45°C for forced aging, and monitored by technological analysis, SPME (-) and - MS (-), Electron Paramagnetic Resonance (EPR). At 45°C, the samples showed a decrease of International Bitterness Units and an increase in color and concentrations of oxidized molecules, and other related with the high temperature (aldehydes and furanic compounds respectively). No differences were observed between samples stored at 6 and 22°C. Sensory analysis showed differences in the perception of paint, sweet, cardboard and freshness attributes in the samples stored at 45°C. No differences were observed in the use of standard and oxygen scavenger caps.
... Extracting wood compounds derived from maturation in oak casks Reducing some off-flavor compounds from previous stages Generally, reducing bitterness and increasing sweetness Increasing volatile compounds Producing microbial compounds that alter beer taste, such as methyl mercaptan, dimethyl sulfoxide, hydrogen sulfide, etc., that promote carbonation, turbidity, superficial films, and excessive viscosity Generating compounds derived from oxidation, including higher alcohols, unsaturated fatty acids, amino acids, and proteins that modify beer flavor [45,93,126,[143][144][145][146][147][148] Bottling Generating sensory-active aldehydes Producing "musty" off-odor derived from cork microbial spoilage or water and other raw materials Increasing the CO2 derived from the development of contaminants [47,[149][150][151][152] Bottle re-fermentation Increasing carbonation Promoting effervescence Generating new flavors Reducing oxidation products [11,17,153] 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. ...
... Nevertheless, the extent to which this phenomenon occurs depends on a number of factors, including the type of beer [93]. 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 [143,144]. ...
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.
... Isovaleric, pentanoic, hexanoic, octanoic, and decanoic acids, together with two 2-phenylethyl acetate and β-phenylethanol, were extracted from beers according to Silva Ferreira et al.. [17] Ten milliliters of degassed beer was mixed with 100 µL of internal standard (1000 mg/L nonanoic acid) in a 20-mL glass flask and shaken for 10 s. Then, 300 µL of n-hexanol was added and the flask shaken for 10 min. ...
Red and brown Flemish sour beers form a distinct class of Belgian beers obtained by mixed (yeast/lactic bacteria) microbial fermentation and often resulting from blending a 1-to-2-year-old beer with a younger one to obtain a balance between acidic character and sweetness. A detailed composition in volatiles (phenols, lactones, esters, alcohols, acids, …) of three beers representative of the red and brown subcategories is presented. GC data were obtained after different extraction procedures, including solvent-assisted flavor evaporation (SAFE) and headspace. The first results showed the influence of Brettanomyces yeast on the phenol and ester contents. An efficient Brettanomyces activity in the red sour beers (especially in Rodenbach Vintage) was observed, favored by long maturation in wooden casks. This was organoleptically perceived by the horsey flavors brought by 4-ethylguaiacol and 4-ethylphenol, and the solvent-like ethyl acetate through esterase activity. The brown Flemish sour beer (produced in stainless steel fermenters) showed significantly more unreduced 4-vinylguaiacol and 4-vinylphenol, although traces of 4-ethylguaiacol and 4-ethylphenol were also detected (most probably here issued from torrefied malts, as suggested by the opposite substituted phenol/guaiacol ratio).
... Another pathway of new flavor formation during bottle conditioning is the release of flavor-active aglycones from their odorless glycoside-bound state by yeast enzymes with glucoside hydrolase activity, such as exo-1,3-β-glucanase (EC 3.2.1.58). The sources of these aromas are glycosides present in hops and malt, which are transferred into beer during the brewing process, with examples including citronellol, vanillin, and β-damascenone [40][41][42]. Some yeast strains are characteristic with pronounced formation of phenolic flavors, which resemble cloves, smoked meat, or medicinal odors. ...
Bottle conditioning refers to a method of adding fermenting wort or yeast suspension in sugar solution into beer in its final package. Additionally denoted as bottle refermentation, this technique has been originally developed to assure beer carbonation, and has further significance related to formation of distinctive sensory attributes and enhancement of sensory stability, which are the phenomena associated with ongoing yeast metabolic activities in the final package. This review covers historical development of the method, describes metabolic pathways applied during refermentation, and explains practical aspects of the refermentation process management. Furthermore, an overview of the traditional and novel approaches of bottle conditioning with mixed yeast bacterial cultures and its impact on the properties of final beer is provided.
... The addition of germ water, rich in micronutrients and soluble proteins, increased the free amino nitrogen levels and Zn concentration in the wort, enhancing its economic value. Then, last but certainly not least, Silva Ferreira et al. answer the question why craft brewers should be advised to use bottle refermentation to improve late-hopped beer stability [9]. As bottle refermentation is widely used in Belgian craft beers, the aim of their work is to assess how this practice might impact their flavor. ...
Beer is a beverage with more than 8000 years of history, and the process of brewing has not changed much over the centuries [...]
Hybridization between Saccharomyces cerevisiae and Saccharomyces eubayanus resulted in the emergence of S. pastorianus , a crucial yeast for lager fermentation. However, our understanding of hybridization success and hybrid vigour between these two species remains limited due to the scarcity of S. eubayanus parental strains. Here, we explore hybridization success and the impact of hybridization on fermentation performance and volatile compound profiles in newly formed lager hybrids. By selecting parental candidates spanning a diverse array of lineages from both species, we reveal that the Beer and PB-2 lineages exhibit high rates of hybridization success in S. cerevisiae and S. eubayanus , respectively. Polyploid hybrids were generated through rare mating techniques, revealing a prevalence of triploids and diploids over tetraploids. Despite the absence of heterosis in fermentative capacity, hybrids displayed phenotypic variability, notably influenced by maltotriose consumption. Interestingly, ploidy levels did not significantly correlate with fermentative capacity, although triploids exhibited greater phenotypic variability. The S. cerevisiae parental lineages primarily influenced volatile compound profiles, with significant differences in aroma production. Interestingly, hybrids emerging from the Beer S. cerevisiae parental lineages exhibited a volatile compound profile resembling the corresponding S. eubayanus parent. This pattern may result from the dominant inheritance of the S. eubayanus aroma profile, as suggested by the over-expression of genes related to alcohol metabolism and acetate synthesis in hybrids including the Beer S. cerevisiae lineage. Our findings suggest complex interactions between parental lineages and hybridization outcomes, highlighting the potential for creating yeasts with distinct brewing traits through hybridization strategies.
The aim of the present work was to compare levels of short chain fatty acids, esters, terpenoids and polyfunctional thiols in (mostly bottle-refermented) commercial Belgian dry-hopped beers before and after 2 years of storage at 20 °C (the usual best-before date in Belgium). Among the hop-derived volatiles, the terpenoids linalool and geraniol, the polyfunctional thiols 3SHol, 3SHA and 3S4MPol, and the esters ethyl isobutyrate, ethyl isovalerate and ethyl heptanoate (up to 499, 53, 0.2, 2, 3, 84, 63, and 19 µg/L, respectively) were found above their sensory thresholds in most fresh dry-hopped beers. The fermentation-derived esters reached concentrations similar to those previously reported for non-dry-hopped beers, with ethyl hexanoate and isoamyl acetate (up to 0.4 and 3.9 mg/L, respectively) often above their sensory thresholds. Except ethyl isovalerate (more than 85% still present), most hop odorants and fermentation esters showed degradation over the 2-year storage period: only 45%–70% of linalool, geraniol, and ethyl hexanoate and even less than 40% for polyfunctional thiols, ethyl isobutyrate, and ethyl heptanoate initial concentrations were detected after storage. How the dry-hopping process affects this degradation was further investigated in model media. Fermentation esters proved to be more strongly impacted in dry-hopped than in non-dry-hopped beers because of hop esterase activity. In addition to being aware of the need to avoid hop esterases, craft brewers are here advised to use bottle refermentation for its ability to regenerate some flavors and consume packaged oxygen. No deleterious effect of yeast, such as short chain fatty acid excretion, was evidenced.
