The application of metabolomics to ascertain the significance of prolonged maturation in the production of lager-style beers

Metrulas, Laura K.; McNeil, Christopher J.; Slupsky, Carolyn M.; Bamforth, Charles W.

doi:10.1002/jib.557

Cited by 3 publications

(5 citation statements)

References 13 publications

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“…It is not clear from this work (Masschelein 1986;Masschelein and Van de Meerssche, 1976) to what extent the authors are differentiating between the action of metabolism of viable yeast as opposed to autolysing yeast in delivering the supposed benefits of prolonged conditioning. Indeed, we should also compare these observations with those of others who applied metabolomics in finding no major difference in the level of a wide range of non-volatile substances between beer aged in the presence or absence of yeast, nor indeed any substantial changes in levels as compared to beer at the end of fermentation (Metrulas et al, 2019). This author suggests that the difference reflects the extent to which autolysis of yeast was occurring in the respective experiments in the two laboratories.…”

Section: Volatile Substancessupporting

confidence: 51%

Provocation: prolonged maturation of beer is of unproven benefit

Bamforth

2023

J Inst Brew.

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Approaches to brewing are suffused with dogmatic insistence that certain techniques are unequivocally linked to the delivery of quality products. Amongst these belief sets is the perseverance with prolonged maturation (or ‘conditioning’) times post-fermentation. Historically the justification for these lagering techniques was to allow settling of solids, carbonation, flavour maturation and removal of chill haze entities. As science and technology have advanced it is unequivocally the case that solids and chill haze precursors can be dealt with in short order and without the need for lengthy treatments. Equally it is perfectly possible to deliver specified levels of carbonation without the need for all the carbon dioxide to be introduced via yeast action. However, there remain many who feel that the nature of carbonation differs depending on which approach is taken. Herein lies one of the research areas that the author proposes. The perception of carbonation is not primarily due to bubble release on the palate, but rather is through the detection of carbonic acid. Is there a difference in the availability of this form of the gas depending on the mode of carbonation and to what extent does the adsorption of the carbonic acid on polypeptides in the beer have a role to play? In terms of flavour, the advocates for lagering insist that there needs to be a handling of vicinal diketones, acetaldehyde, and hydrogen sulphide. However, all of these can be controlled through attention to primary fermentation. Then, the proponents for maturation insist that there is a desirable release of non-volatile materials into beer, which substances supposedly benefit the balance and mouthfeel of the lager. These include amino acids and nucleotides. It seems to this author however that the likeliest explanation for the greatly increased levels of these materials and of pH is autolysis of yeast. This, together with the disadvantageous impact of increased free amino nitrogen and higher pH on aspects such as biological stability, flavour stability and foam, should convince any brewer that there is a sound argument for avoiding the prolonged contact of beer with yeast. Indeed, a metabolomic approach to studying changes in non-volatile substances under conditions where there is little or no autolysis, revealed no detectable changes in any entity. The author is open to being convinced that there are yet unidentified materials that are developed (whether through the action of viable yeast or by yeast autolysis) as beer is stored, substances which can be proven through sound organoleptic investigation to benefit the flavour of beer. Perhaps the Japanese term kokumi is what we are looking for here: ‘rich taste’. This is believed to be afforded by γ-glutamyl peptides and, inter alia, these are to be found in yeast extracts. Herein lies the second experimental approach that the author recommends for pursuit.

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Section: Volatile Substancessupporting

confidence: 51%

Provocation: prolonged maturation of beer is of unproven benefit

Bamforth

2023

J Inst Brew.

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“…As previously discussed, trigonelline (lower part of Figure 3 g) is among the most influential metabolites for distinguishing the pale lager group and the IPA group. Trigonelline is very interesting [ 19 , 43 , 56 ] and it has been recently identified in beer and described as a plant-associated metabolite whose concentration increases with boiling [ 43 ]. Hops are generally added right before boiling the beer wort, so that the alpha acids can be extracted from the raw hops and thermally isomerized into iso-alpha acids, giving the beer its characteristic bitter taste [ 70 ].…”

Section: Resultsmentioning

confidence: 99%

“…An example of the MCR peak resolution and identification process is shown in Figure 1 , investigating the amino acid valine which is characterized by a quite complex spin system resulting in a symmetric multiplet. Its presence in beer was reported by many bibliographic sources [ 13 , 20 , 43 , 46 , 50 , 56 ], even though only Nord et al also reported its chemical shift and assignment [ 14 ]. In the example, four MCR models are shown: in each of them, it is possible to identify one resolved spectral profile that matches the actual complex signal of valine (in red in Figure 1 b–e), whose correct profile was recovered from the reference library of Chenomx ( Figure 1 f, a screenshot from the software’s interface).…”

Section: Methodsmentioning

confidence: 99%

“…As anticipated in Section 2.2.1 , tentative identification of the extracted compounds was performed by comparing the resolved NMR signals to literature sources [ 2 , 13 , 14 , 17 , 19 , 20 , 43 , 45 , 46 , 48 , 50 , 53 , 56 , 57 , 58 ]. To make some identifications and assignments more robust, the information provided by the reference library of Chenomx and the NMR spectra searchable on the Human Metabolome Database (HMDB, [ 59 ]) were also used.…”

Section: Methodsmentioning

confidence: 99%

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A Metabolomic Approach to Beer Characterization

et al. 2021

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The consumers’ interest towards beer consumption has been on the rise during the past decade: new approaches and ingredients get tested, expanding the traditional recipe for brewing beer. As a consequence, the field of “beeromics” has also been constantly growing, as well as the demand for quick and exhaustive analytical methods. In this study, we propose a combination of nuclear magnetic resonance (NMR) spectroscopy and chemometrics to characterize beer. 1H-NMR spectra were collected and then analyzed using chemometric tools. An interval-based approach was applied to extract chemical features from the spectra to build a dataset of resolved relative concentrations. One aim of this work was to compare the results obtained using the full spectrum and the resolved approach: with a reasonable amount of time needed to obtain the resolved dataset, we show that the resolved information is comparable with the full spectrum information, but interpretability is greatly improved.

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“…From the days of his employment within a brewing company that did not see the merits of prolonged aging of beer, the present author has been sceptical of its necessity. Laura Metrulas and colleagues used metabolomics to illustrate our inability to find significant changes in non‐volatile molecules in beers during prolonged storage . [We had previously explored the use of this technique to address impacts of late and dry hopping .]…”

Section: Flavourmentioning

confidence: 99%

The Horace Brown Medal. Forever in focus: researches in malting and brewing sciences

Bamforth

2020

J. Inst. Brew.

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The paper reviews a career of more than forty years researching topics in malting and brewing science. Some themes attracted particularly close attention, namely the endosperm cell walls of barley, dimethyl sulphide, flavour stability, foam and the impact of beer on health. However, the scope has been far broader than that. The underlying imperative was to pursue research that was close to application and always focussed on a specific need in the processes involved in the production of beer. © 2020 The Institute of Brewing & Distilling

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The application of metabolomics to ascertain the significance of prolonged maturation in the production of lager-style beers

Cited by 3 publications

References 13 publications

Provocation: prolonged maturation of beer is of unproven benefit

Provocation: prolonged maturation of beer is of unproven benefit

A Metabolomic Approach to Beer Characterization

The Horace Brown Medal. Forever in focus: researches in malting and brewing sciences

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