Reference Beers Research Articles

Is malting an absolute must? Native triticale as a stand-in for barley malt in the brewing process.

To remain competitive, brewers must innovate by incorporating novel elements beyond traditional styles. Thus, exploring triticale as a modern substitute for barley malt is promising, especially given its higher amylolytic activity compared to barley. This study aimed to assess the impact of substituting up to 50% of barley malt with unmalted triticale on green beer quality, encompassing multiple stages from wort production to primary fermentation at a laboratory scale. Triticale-based worts (ratios 10-50%) had lower extract content than 100% barley malt. However, incorporating 10% of triticale led to only a 1% decrease in extract content compared to the all-malt wort. Shearzyme® 500L, an endo-1,4-β-xylanase with β-glucanase side activity, effectively addressed wort viscosity by breaking down arabinoxylans and β-glucans in triticale cell walls. All triticale-based beers exhibited lower ethanol content compared to reference beer, as is typical when using adjuncts. In green beer, a 50% triticale ratio lowered ethanol content by 16% (without enzyme) and 19% (with enzyme) compared to 100% malt beer. However, green beer with 10% triticale had satisfactory levels of total polyphenol and vicinal diketone content, among other parameters. Commercial enzyme application significantly enhanced proteolytic activity within the grain. Fermentations of enzyme-treated worts showed higher amino acid levels, further confirming the increased proteolytic activity facilitated by the chosen enzyme. Overall, this study provides a comprehensive analysis of the brewing process using native triticale. Building on this foundation, future studies will focus on optimizing mashing conditions to enhance the fermentation profile of the wort. © 2024 Society of Chemical Industry.

Quantitative Antioxidant Profiling Throughout Beer Brewing Followed by Discovery and Isolation of Precursors from Barley (Hordeum vulgare L.).

The application of high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) revealed the origin and evolution of antioxidants during the brewing process of hopped and unhopped reference beer. As tachioside (3-methoxy-4-hydroxyphenyl-β-d-glucopyranoside), arbutin (4-hydroxyphenyl-β-d-glucopyranoside), and hordatines clearly increased during the fermentation step, the raw material barley was investigated as a source of the corresponding precursors. Therefore, 4-hydroxyphenyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside, 4-hydroxy-3-methoxyphenyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside, 4-hydroxy-3-methoxyphenyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside, and 4-hydroxy-2-methoxyphenyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside were isolated from barley for the first time, and identified using liquid chromatography-mass spectrometry (LC-MS) and one-dimensional/two-dimensional-nuclear magnetic resonance (1D/2D-NMR) experiments. Moreover, hordatine glucosides A, B, and C were isolated and identified from barley, and hordatine C glucoside was characterized for the first time. A fermentation model followed by HPLC-MS/MS analysis substantiated the release of tachioside from 4-hydroxy-3-methoxyphenyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside by Saccharomyces cerevisiae. Quantitation experiments monitoring the content in wheat, barley, and different barley malt types demonstrated a wide range of concentrations, providing a basis for further comprehensive investigations to optimize the antioxidant yield in beer to contribute to improved flavor stability.

Sourdough Yeast Strains Exhibit Thermal Tolerance, High Fermentative Performance, and a Distinctive Aromatic Profile in Beer Wort.

The increasing popularity of home brewing and the fast evolution of craft beer companies have fuelled the interest in novel yeasts as the main actors diversifying the beer portfolio. Here, we have characterized the thermal tolerance and brewing-related features of two sourdough (SD) isolates of Saccharomyces cerevisiae, SDy01 and SDy02, at different temperatures, 20 and 37 °C, comparing them with commercial brew strains, AaB and kNB. The SD strains exhibited tolerance to the main brewing-related stress conditions and increased growth rates and lower lag phases than the reference beer strains at both temperatures. Consistent with this, SDy01 and SDy02 displayed higher fermentative activity in terms of sugar rate depletion and the release of metabolic by-products. Moreover, SDy01 and SDy02 brewing at 20 °C increased their total amount of volatile compounds (VOCs), in particular, their esters and carboxyl compounds, as compared to the reference AaB strain. In contrast, fermentation at 37 °C resulted in a drastic reduction in the number of VOCs in wort fermented with SD yeast, especially in its level of esters. In conclusion, our results stress the high fermentative performance of SD strains in beer wort and their ability to provide a complex and specific aromatic profile at a wide range of temperatures.

Dip Hopping Technique and Yeast Biotransformations in Craft Beer Productions

This paper evaluates the effects of an alternative hopping technique, called dip hopping, on beer. This technique involves infusing hops in hot water (or in a portion of wort) and subsequently combining the infusion with the wort (after wort cooling) directly in the fermenter when the yeast is added for fermentation. The reference beers were produced employing the “traditional” late hopping technique, and the experimental beers were produced using the dip hopping technique. A variety of hops with a significant concentration of essential oil and a strain of yeast with high β-glucosidic activity capable of releasing aromatic molecules from precursors supplied by hops were used. The samples were analysed in terms of alcohol content, degree of attenuation, colour, and bitterness. Sensory analysis and gas chromatography analysis were also performed. The data showed statistically significant differences between the reference beers and the experimental beers, with the latter featuring greater hints of citrus, fruity, floral, and spicy aromas. As an overall effect, there was an increase in the olfactory and gustatory pleasantness of the beers produced with the dip hopping technique.

Integration of Arthrospira platensis (spirulina) into the brewing process to develop new beers with unique sensory properties

Microalgae, and particularly the cyanobacterium Arthrospira platensis (spirulina), have attracted much attention due to their wide range of uses. The potential use of spirulina in food is mainly driven by its high content of macro and micronutrients including proteins, γ-linolenic acid, sulfated polysaccharides, minerals, vitamins, and the natural pigment phycocyanin. Despite these potential benefits, spirulina is still not widely used in the food industry due to numerous technological challenges during manufacturing or specific sensory issues in the final product. This research deals with the feasibility of integrating spirulina into the brewing process to create a tasty beer with high consumer acceptance. In the novel recipes, 5% (w/w) of the malt was replaced by spirulina powder. The first part of the study investigated inclusion at different time points throughout manufacturing of a reference beer style (mild pale ale). Compared to the control, alcoholic fermentation was slightly influenced by cyanobacterial biomass but resulted in a beer with a typical beer-like character. Sensory evaluations including a simple descriptive test, a popularity analysis, and Just-About-Right-Questions, indicated a complex alteration in the sensory properties. This includes a dominant algal taste that disturbs the character of the pale ale beers but also a deep blue color of the beer, if spirulina was included during the wort cooling phase. Based on these results, another set of beers with a higher original extract concentration and increased hop dosages was produced. These beers had a high popularity (6.0 original TESTSCORE; 7.12 and 6.64 optimized TESTSCORE), and also exhibited a deep blue color due to the natural pigment phycocyanin from spirulina. Further, bitterness and algal taste was rated by most of the panelists to be “just right” and the simple descriptive test indicated “sweetness” as important attribute which was not expected for this hoppy beer style.

Repurposing brewery contaminant yeast as production strains for low-alcohol beer fermentation.

A number of fungal isolates were recently obtained from a survey of the microbiota of multiple breweries and brewery products. Here, we sought to explore whether any of these brewery contaminants could be repurposed for beneficial use in beer fermentations, with particular focus on low-alcohol beer. There were 56 yeast strains first screened for the utilization of different carbon sources, ability to ferment brewer's wort, and formation of desirable aroma compounds. A number of strains appeared maltose-negative and produced desirable aromas without obvious off-flavours. These were selected for further scaled-up wort fermentations. The selected strains efficiently reduced wort aldehydes during fermentation, thus eliminating undesirable wort-like off-flavours, and produced a diverse volatile aroma profile. Two strains, Trigonopsis cantarellii and Candida sojae, together with a commercial Saccharomycodes ludwigii reference strain, were selected for 30-L-scale wort fermentations based on aroma profile and similarity to a commercial reference beer during sensory analysis using projective mapping. Both strains performed comparably to the commercial reference, and the T.cantarellii strain in particular, produced low amounts of off-flavours and a significantly higher amount of the desirable monoterpene alcohol trans-geraniol. The strain was also sensitive to common food preservatives and antifungal compounds and unable to grow at 37°C, suggesting it is relatively easily controllable in the brewery, and appears to have low risk of pathogenicity. This study shows how the natural brewery microbiota can be exploited as a source of non-conventional yeasts for low-alcohol beer production.

Peptidomics of an industrial gluten-free barley malt beer and its non-gluten-free counterpart: Characterisation and immunogenicity

Recent research suggests that gluten-free beers by prolyl-endopeptidase treatment may not be safe for coeliac disease (CD) patients. Therefore, the gluten peptidome of an industrial gluten-free prolyl-endopeptidase treated malt beer (<10 ppm gluten) was compared to its untreated counterpart (58 ppm gluten) as a reference. NanoLC-HRMS analysis revealed the presence of 155 and 158 gluten peptides in the treated and reference beer, respectively. Characterisation of the peptides in treated beer showed that prolyl-endopeptidase activity was not complete with many peptides containing (multiple) internal proline-residues. Yet, prolyl-endopeptidase treatment did eliminate complete CD-immunogenic motifs, however, 18 peptides still contained partial, and potentially unsafe, motifs. In the reference beer respectively 7 and 37 gluten peptides carried (multiple) complete and/or partial CD-immunogenic motifs. Worrying is that many of these partial immunogenic gluten peptides do not contain a recognition epitope for the R5-antibody and would be overlooked in the current ELISA analysis for gluten quantification.

Brewing potential of the wild yeast species Saccharomyces paradoxus

Saccharomyces paradoxus is commonly isolated from environmental samples in Northern Europe and North America, but is rarely found associated with fermentation. However, as novelty has become a selling point in beer markets, interest toward non-conventional and local yeasts is increasing. Here, we report the first comprehensive investigation of the brewing potential of the species. Eight wild strains of S. paradoxus were isolated from oak trees growing naturally in Finland, screened in a series of fermentation trials and the most promising strain was selected for lager beer brewing at pilot scale (40 l). Yeasts were evaluated according to their ability to utilize wort sugars, their production of flavour-active aroma volatiles, diacetyl and organic acids, and sensorial quality of beers produced. All strains could assimilate maltose but this occurred after a considerable lag phase. Once adapted, most wild strains reached attenuation rates close to 70%. Adaptation to maltose could be maintained by re-pitching and with appropriate handling of the adapted yeast. Fermentation at 15 °C with the best performing strain was completed in 17 days. Maltose was consumed as efficiently as with a reference lager yeast, but no maltotriose use was observed. Bottled beers were evaluated by a trained sensory panel, and were generally rated as good as, or better than, reference beers. S. paradoxus beers were considered full-bodied and had a relatively clean flavour profile despite the presence of the clove-like 4-vinyl guaiacol. In conclusion, S. paradoxus exhibits a number of traits relevant to brewing, and with appropriate handling could be applied industrially.

Co-fermentation Involving Saccharomyces cerevisiae and Lactobacillus Species Tolerant to Brewing-Related Stress Factors for Controlled and Rapid Production of Sour Beer.

Increasing popularity of sour beer urges the development of novel solutions for controlled fermentations both for fast acidification and consistency in product flavor and quality. One possible approach is the use of Saccharomyces cerevisiae in co-fermentation with Lactobacillus species, which produce lactic acid as a major end-product of carbohydrate catabolism. The ability of lactobacilli to ferment beer is determined by their capacity to sustain brewing-related stresses, including hop iso-α acids, low pH and ethanol. Here, we evaluated the tolerance of Lactobacillus brevis BSO464 and Lactobacillus buchneri CD034 to beer conditions and different fermentation strategies as well as their use in the brewing process in mixed fermentation with a brewer’s yeast, S. cerevisiae US-05. Results were compared with those obtained with a commercial Lactobacillus plantarum (WildBrewTM Sour Pitch), a strain commonly used for kettle souring. In pure cultures, the three strains showed varying susceptibility to stresses, with L. brevis being the most resistant and L. plantarum displaying the lowest stress tolerance. When in co-fermentation with S. cerevisiae, both L. plantarum and L. brevis were able to generate sour beer in as little as 21 days, and their presence positively influenced the composition of flavor-active compounds. Both sour beers were sensorially different from each other and from a reference beer fermented by S. cerevisiae alone. While the beer produced with L. plantarum had an increased intensity in fruity odor and dried fruit odor, the L. brevis beer had a higher total flavor intensity, acidic taste and astringency. Remarkably, the beer generated with L. brevis was perceived as comparable to a commercial sour beer in multiple sensory attributes. Taken together, this study demonstrates the feasibility of using L. brevis BSO464 and L. plantarum in co-fermentation with S. cerevisiae for controlled sour beer production with shortened production time.

Investigations on the Impact of the Special Flavor Hop Variety Huell Melon on the Odor-Active Compounds in Late Hopped and Dry Hopped Beers.

Bottom-fermented and top-fermented beers, both either late or dry hopped with Huell Melon hops, and respective reference beers without late or dry hopping were subjected to a comparative odorant screening by aroma extract dilution analyses. On the basis of differences in the FD factors, 14 odorants were identified as hop-derived. Among them were ethyl 2-methylpropanoate, methyl 2-methylbutanoate, ethyl 2-methylbutanoate, propyl 2-methylbutanoate, myrcene, linalool, and geraniol. Differences between late hopped, dry hopped, and reference beers were substantiated by quantitation. Results showed minimal transfer of myrcene from hops into beer. Moderate transfer was observed for propyl 2-methylbutanoate, geraniol, and linalool. Process-induced changes of ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, and methyl 2-methylbutanoate were beyond a direct transfer from hops into beer, suggesting a formation from the corresponding hop-derived carboxylic acids by yeast. Spiking experiments revealed that linalool and propyl 2-methylbutanoate contributed particularly to the characteristic aroma of beers flavored with Huell Melon hops.

Applicability of different brewhouse technologies and gluten-minimization treatments for the production of gluten-free (barley) malt beers: Pilot- to industrial-scale

The fate of gluten proteins and (poly)peptides throughout the brewing process of reference and gluten-minimized all-malt beers was monitored on both pilot-scale and industrial-scale. Common process steps such as wort separation, cooking, wort and beer clarification already significantly reduce the mass of gluten proteins (72–99%). Nevertheless, gluten derived (poly)peptides remained present at high concentrations in the final reference beers (58–397 ppm). A lauter tun, with course husk material as filter bed, showed to be more effective in reducing the mass of gluten proteins than a mash filter (33% vs. 18%). The mass of gluten proteins and (poly)peptides could be further significantly reduced (16–89% and 33–81% respectively) depending on the use of tannins, AN-PEP (Prolyl-endopeptidase from Aspergillus niger) and silica gel. To render all-barley malt beers gluten-free (≤20 ppm) (EC No. 41/2009, 2009) gluten-minimization treatments with AN-PEP and silica gel were combined successfully; these beers contained <5 ppm gluten proteins and <10 ppm gluten (poly)peptides.

Production of gluten-free beer by peptidase treatment

Celiac disease patients adhering to a gluten-free diet are allowed to drink only beer surrogates, which differ from barley-based beers in terms of aroma and taste. An enzyme-active malt extract produced from special barley malt with high gluten-specific peptidase activity was applied in the brewing process to obtain gluten-free beer in line with the German beer regulations. A commercially available, highly active prolyl endopeptidase from Aspergillus niger (AN-PEP) was also used. Results showed that both AN-PEP and the enzyme-active malt extract were able to degrade celiac-active peptides in a beer matrix. AN-PEP was more stable than malt enzymes under conditions of variable temperature and ethanol content. Analysis by a competitive R5 ELISA indicated that the resulting beers were gluten-free. Aroma and taste were significantly better compared to a commercial gluten-free millet beer. Additionally, the gluten-free beers and the gluten-containing reference beer had comparable quality attributes, except for the foam stability of the extract-treated beer. Identification of hordein peptides in the beers by LC-MS2 analysis after chymotryptic digestion partly conflicted with the ELISA results and highlighted the difficulties of gluten quantitation in a beer matrix as well as the need for an independent and reliable method to detect partially hydrolyzed gluten in fermented beverages.

Physicochemical characterization of sahti, an ‘ancient’ beer style indigenous to Finland

Sahti, a strong, unhopped farmhouse beer flavoured with juniper, is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and, while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5°P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g L−1 were higher than in reference beers (commercial lager, wheat beer and porter). These features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3–13 IBU) owing to the absence or moderate use of hops. All samples contained detectable levels of the clove-like compound 4-vinylguaiacol owing to the use of baker's rather than brewer's yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style. Copyright © 2015 The Institute of Brewing & Distilling

Effects of wort clarifying by using carrageenan on diatomaceous earth dosage for beer filtration

Poreda A., Zdaniewicz M., Sterczynska M., Jakubowski M., Puchalski C. (2015): Effects of wort clarifying by using carrageenan on diatomaceous earth dosage for beer filtration. Czech J. Food Sci., 33: 392–397. Diatomaceous earth makes a great contribution to the amount of brewing waste. In this work, attempts were made to reduce the dosage of diatomaceous earth used during beer filtration, via the application of carrageenan at the stage of wort boiling. Carrageenan was added to the boiling wort (50 mg/l) and, after fermentation, the beer was filtered using different doses of diatomaceous earth (0.05–0.40 g/l). The filtration performance of beers obtained from car rageenan-pretreated wort was compared with the filtration of reference beer. It was found that beer produced from wort treated with carrageenan, had a significantly lower haze before filtration compared to the reference beer (other quality parameters showed no significant differences). The reference beer had a higher haze after filtration with 0.40 g/l of diatomaceous earth than the carrageenan pre-clarified beer after filtration with 0.05 g/l. It was concluded that the use of preliminary clarification of wort with carrageenan allows for a significant reduction of the diatomaceous earth application while maintaining high clarity of beer.

Occurrence of Odorant Polyfunctional Thiols in Beers Hopped with Different Cultivars. First Evidence of an S-Cysteine Conjugate in Hop (Humulus lupulus L.)

Forty-one thiols, mainly β-sulfanylalkyl acetates, β-sulfanylalkyl alcohols, and β-sulfanylalkyl carbonyls, were recently evidenced in hop. In a beer hopped with the Tomahawk cultivar, most of them were found at higher levels than expected. The aim of the present work was to investigate the polyfunctional thiols in beers hopped with different varieties. A few thiols proved not to come only from hop (mainly 2-sulfanylethyl acetate, μg/L levels, and 1-sulfanylpentan-3-one and 1-sulfanylpentan-3-ol, ng/L levels, internal standard (IST) equivalents). The thiol profile of Saaz-hopped beer proved similar to that of the reference beer produced without hop. A high level of 3-sulfanyloctan-1-ol emerged as an indicator of the use of Tomahawk hop (140 ng/L, IST equivalents; FD (flavor dilution) = 65536). In both Cascade- and Tomahawk-hopped beers, 3-sulfanylhexan-1-ol and 3-sulfanylheptan-1-ol were smelled at high flavor dilutions, although only for the latter, significant amounts of the unreduced 3-sulfanylheptanal were found in hop. As already claimed for hop authentication, 3-sulfanyl-4-methylpentan-1-ol remains a good marker of Nelson Sauvin-hopped beers (548 ng/L, IST equivalents; FD = 65536), together with 4-sulfanyl-4-methylpentan-2-one (128 ng/L, FD = 4096). As illustrated by the huge production occurring during fermentation, accurate prediction of hop varietal impact requires quantitating thiol adducts in hop. S-3-(1-Hydroxyhexyl)cysteine was evidenced here for the first time in Cascade hop.

Analysis of Free Fatty Acids, Fusel Alcohols, and Esters in Beer: An Alternative to CS2 Extraction

Beer flavor compounds of routine interest were analyzed by gas chromatography using either direct headspace injection or solvent extraction. The headspace chromatographic method described here makes it possible to analyze dimethyl sulfide, ethyl acetate, propanol, isobutanol, isoamyl acetate, isoamyl and amyl alcohols, and less volatile compounds such as ethyl caproate (168-degrees-C) and ethyl caprylate (208-degrees-C) in less than 20 min. Two calibration methods are described: daily calibration or the use of an internal reference beer system, which considerably simplifies the calibration procedure for long-term use. Although rapid and accurate, headspace analysis discriminates against the less volatile compounds. A complementary chromatographic method, both quick and simple, was designed to assay amounts of caproic, caprylic, and capric acids; beta-phenylethanol; and beta-phenylethylacetate in fermenting wort and beer. In combination with headspace analysis, this method using hexanol as the extracting solvent yielded beer aroma profiles similar to those obtained with the carcinogenic solvent CS2. Repeatability of the two solvent extraction procedures was studied by replicating the analyses. The combined techniques were used to investigate relationships between flavor compounds and their formation in 48 lager beers.

Analysis of Free Fatty Acids, Fusel Alcohols, and Esters in Beer: An Alternative to CS2Extraction

Beer flavor compounds of routine interest were analyzed by gas chromatography using either direct headspace injection or solvent extraction. The headspace chromatographic method described here makes it possible to analyze dimethyl sulfide, ethyl acetate, propanol, isobutanol, isoamyl acetate, isoamyl and amyl alcohols, and less volatile compounds such as ethyl caproate (168°C) and ethyl caprylate (208°C) in less than 20 min. Two calibration methods are described: daily calibration or the use of an internal reference beer system, which considerably simplifies the calibration procedure for long-term use. Although rapid and accurate, headspace analysis discriminates against the less volatile compounds. A complementary chromatographic method, both quick and simple, was designed to assay amounts of caproic, caprylic, and capric acids; β-phenyl-ethanol; and β-phenylethylacetate in fermenting wort and beer. In combination with headspace analysis, this method using hexanol as the extracting solvent yielded beer aroma profiles similar to those obtained with the carcinogenic solvent CS2. Repeatability of the two solvent extraction procedures was studied by replicating the analyses. The combined techniques were used to investigate relationships between flavor compounds and their formation in 48 lager beers.

The technology and properties of beer produced from unmalted sorghum or maize grains

Three basic samples of beers were produced: A, B and C. The grit of A and B contained as unmalted adjuncts 15% (plus 10% of saccharose) and 25% of sorghum grains or maize grits, respectively. The reference beer C was produced with barley malt only. The study of the effects of the unmalted adjuncts on the brewing and the quality of beer revealed that: (a) the use of 15 to 20% of maize or 25% of sorghum increased the content of iso-compounds in wort; (b) the combination of maize grit and saccharose improved the colour of the wort and beer; (c) the addition of 25% sorghum extended saccharification time, slowed down both wort and beer filtration and also produced wort of a darker colour and beer with a slightly bitter aftertaste.