Influence of Lauter Turbidity on Wort Composition, Fermentation Performance and Beer Quality - A Review

Kühbeck, Florian; Back, Werner; Krottenthaler, Martin

doi:10.1002/j.2050-0416.2006.tb00716.x

Cited by 43 publications

(31 citation statements)

References 29 publications

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“…With regard to turbidity, the fatty acids palmitic acid (C16) and linoleic acid (C18:2) in particular are considered to have a major impact, whereas myristic acid (C14), stearic acid (C18), oleic acid (C18:1) and linolenic acid (C18:3) play a minor part on turbidity (Stewart and Martin, , Anness and Reed, , Narziss and Mück, , Schuster, , Verstrepen et al., , Wackerbauer et al., , Mück, ). A higher amount of long‐chain fatty acids in combination with zinc can improve the fermentation process, but can also have negative effects on foam and flavour stability in the final beer (Hartmann, , Kühbeck et al., ). Ahvenainen et al () recommended a total content of fatty acids in wort of 10–20 mg L −1 (Ahvenainen et al., ).…”

Section: Introductionsupporting

confidence: 63%

Turbidity potentials of single long‐chain fatty acids and gelatinised starch in synthetic lautering wort

Holtz

Gastl

Becker

2015

Int J of Food Sci Tech

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Summary The turbidity potentials of long‐chain fatty acids as well as gelatinised starch were investigated in synthetic lautering wort to determine their contribution to turbidity according to concentration. Synthetic wort proved to be a standardised and reproducible model solution. Concentration series of gelatinised starch and single long‐chain fatty acids as pure substances showed high correlations between concentrations and turbidity levels of turbidity 11° and turbidity 90° measurements. Gelatinised barley starch has the turbidity potential of 0.04 EBC/(mg L−1) on turbidity 11° levels. Regarding long‐chain fatty acids, saturated fatty acids showed distinctly higher turbidity potentials on turbidity 11° (≥0.32 EBC/(mg L−1) and turbidity 90° (≥0.15 EBC/(mg L−1) than unsaturated fatty acids. The turbidity potential of the saturated fatty acids corresponded with their chain lengths, with stearic acid (18:0) showing the highest turbidity potential. However, the impact on turbidity is primarily determined by concentration and not by turbidity potential.

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Section: Introductionsupporting

confidence: 63%

Turbidity potentials of single long‐chain fatty acids and gelatinised starch in synthetic lautering wort

Holtz

Gastl

Becker

2015

Int J of Food Sci Tech

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“…Signature transcripts for diagnosing Zn bioavailability in industrial media. In complex industrial fermentation media, such as wort or other plant biomass hydrolysates, Zn can form complexes with several medium components, thereby reducing its bioavailability for yeast (34,41,42). This limits the relevance of chemical analyses of the Zn content to test the bioavailability of zinc in wort and other industrial media.…”

Section: Discussionmentioning

confidence: 99%

Physiological and Transcriptional Responses of Saccharomyces cerevisiae to Zinc Limitation in Chemostat Cultures

Nicola

Hazelwood

Hulster

et al. 2007

Appl Environ Microbiol

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Transcriptional responses of the yeast Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under limiting and abundant Zn concentrations in chemostat culture. To investigate the context dependency of this transcriptional response and eliminate growth rate-dependent variations in transcription, yeast was grown under several chemostat regimens, resulting in various carbon (glucose), nitrogen (ammonium), zinc, and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified, and the set enabled the definition of the Zn-specific Zap1p regulon, comprised of 26 genes and characterized by a broader zinc-responsive element consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large number of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified.

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“…A variety of technological and technical aspects of lauter turbidity, as well as its influence on wort composition, fermentation performance and wort quality have been thoroughly discussed in the previous review paper in this issue. 21 In previously reported pilot scale trials (60 L per brew), turbid (>100 EBC) and clear worts (approximately 20 EBC) were produced by variation of the lauter procedure which caused increased long-chain fatty acid concentra-tions, a slight increase of zinc concentrations (+ 0.03-0.04 mg/L), but no increase in iodine numbers in kettle-up (kettle-full) worts 23 (kettle-up being defined as approximately 5 min after the beginning of the boil). Further, a faster fermentation, no deterioration of foam stability, an excellent non-biological stability, and a tendency towards higher 2-phenyl ethanol and lower acetaldehyde concentrations in beer were the results of extremely turbid lautering coupled to a high yeast vitality.…”

Section: Introductionmentioning

confidence: 99%

Influence of Lauter Turbidity on Wort Composition, Fermentation Performance and Beer Quality in Large-Scale Trials

Kühbeck

Back

Krottenthaler

2006

Journal of the Institute of Brewing

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Different lauter turbidities (standard 43 EBC vs. turbid 82 EBC on average) were obtained by variation of the lauter procedure, particularly deep raking, in this study. The resulting worts were used for repitching the respective yeast into six subsequent fermentation cycles. The resulting beers were investigated in terms of flavour quality, flavour stability, non-biological stability and foam stability. Worts gained from turbid lautering showed very similar analytical data compared to the controls (except for a slight but significant increase in linoleic acid). There was an improvement in fermentation performance in terms of a pH decrease and a decrease in extract. The resulting beers were quite similar, and the staling indicators increased slightly, but not significantly, due to turbid lautering. Both types of beer were evaluated on tasting as being of a high flavour quality and neither a professional panel nor a non-professional (customer) panel was able to distinguish the difference, between standard and turbid lautering, in terms of fresh and forced aged beers. Due to turbid lautering the non-biological stability appeared to be slightly, but not significantly, decreased while on the other hand the foam stability was significantly improved due to turbid lautering. In conclusion, fermentation performance may be improved by more turbid lautering, and the negative consequences often reported for the resulting beers appear to be overestimated, since the quality parameters of the final beers had not deteriorated significantly.

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Influence of Lauter Turbidity on Wort Composition, Fermentation Performance and Beer Quality - A Review

Cited by 43 publications

References 29 publications

Turbidity potentials of single long‐chain fatty acids and gelatinised starch in synthetic lautering wort

Turbidity potentials of single long‐chain fatty acids and gelatinised starch in synthetic lautering wort

Physiological and Transcriptional Responses of Saccharomyces cerevisiae to Zinc Limitation in Chemostat Cultures

Influence of Lauter Turbidity on Wort Composition, Fermentation Performance and Beer Quality in Large-Scale Trials

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