Advertisement

Malt-induced premature yeast flocculation: current perspectives

  • Apostolos G. Panteloglou
  • Katherine A. Smart
  • David J. CookEmail author
Review

Abstract

Premature yeast flocculation (PYF) is a sporadic problem for the malting and brewing industries which can have significant financial and logistical implications. The condition is characterised by abnormally heavy (and sometimes early) flocculation of yeast during brewery fermentations. The resulting low suspended yeast cell counts towards the end of the fermentation can result in flavour defects and incomplete attenuation (fermentation of sugars to alcohol). Despite several decades of research into the phenomenon, its precise nature and mechanisms have not been fully elucidated. In part this is because the term PYF has become a ‘catch-all’ syndrome which can have multiple origins. Furthermore, there are complex interactions in the malting and brewing processes which together mean that the PYF status of a malt sample is hard to predict at a generic level. Whether or not PYF is observed depends not only on barley quality, but on process factors in the maltings and to a substantial extent on the brewing yeast strain concerned. This article highlights the significance of PYF, and reviews current knowledge relating to the origins of this complex phenomenon.

Keywords

PYF Brewing Fermentation performance Yeast flocculation Malt quality 

Abbreviations

PYF

Premature yeast flocculation

PYF+

A premature yeast flocculation positive sample (barley, malt or wort giving rise to PYF)

PYF−

A premature yeast flocculation negative sample (control barley, malt or wort sample yielding normal flocculation characteristics)

ns-LTP

Non-specific lipid transfer protein

T-RFLP

Terminal restriction fragment length polymorphism

Notes

Acknowledgments

The authors would like to thank the UK Home Grown Cereal Authority for financial support. Professor Katherine Smart is the SABMiller Professor of Brewing Science and gratefully acknowledges SABMiller for their continued support.

References

  1. 1.
    Armstrong K, Bendiak D (2007) PYF malt: practical brewery observations of fermentability. Tech Q Master Brew Assoc Am 44(1):40–46Google Scholar
  2. 2.
    Axcell B, Van Nierop S, Vundla W (2000) Malt induced premature yeast flocculation. Tech Q Master Brew Assoc Am 37(4):501–504Google Scholar
  3. 3.
    Axcell BC (2003) Impact of wort composition on flocculation. In: Smart KA (ed) Brewing yeast fermentation performance, 2nd edn. Blackwell Science, Oxford, pp 120–128Google Scholar
  4. 4.
    Axcell BC, Morall P, Tulez R, Murray JP (1984) Malt specifications: a safe guard or restriction on quality. Tech Q Master Brew Assoc Am 21:101–106Google Scholar
  5. 5.
    Axcell BC, Tulez R, Mulder CJ (1986) The influence of the malting process on malt fermentability performance. In: Proceedings of the 19th convention of the Institute of Brewing, Australia and New Zealand section, Hobart, pp 63–69Google Scholar
  6. 6.
    Bayly JC, Douglas LM, Pretorius IS, Bauer FF, Dranginis AM (2005) Characteristics of Flo11-dependent flocculation in Saccharomyces cerevisiae. FEMS 5:1151–1156Google Scholar
  7. 7.
    Bony M, Barre P, Blondin B (1998) Distribution of the flocculation protein, Flop, at the cell surface during yeast growth: the availability of flop determines the flocculation level. Yeast 14:25–35PubMedCrossRefGoogle Scholar
  8. 8.
    Bossier P, Goethals P, Rodriques-Pousada C (1998) Constitutive flocculation in Saccharomyces cerevisiae through overexpression of the GTS1 gene, coding for a ‘Glo’-type Zn-finger-containing protein. Yeast 13:717–725CrossRefGoogle Scholar
  9. 9.
    Damas-Buenrosto LC, Gracia-Gonzalez G, Hernandez-Luna CE, Galan-Wong LJ, Pereyra-Alferez B, Sierra-Benavides JA (2008) Detection of FLO genes in lager and wild yeast strains. J Am Soc Brew Chem 66(3):184–187Google Scholar
  10. 10.
    Evans E, Kaur M (2009) Keeping sleepy yeast awake until bedtime. Understanding and avoiding PYF. Brewer Distill Int 5(5):38–40Google Scholar
  11. 11.
    Fujino S, Yoshida T (1976) Premature flocculation of yeast induced by some wort constituents. Rep Res Lab Kirin Brew Co Ltd 19:45–53Google Scholar
  12. 12.
    Govender P, Bester M, Bauer FF (2010) FLO gene-dependent phenotypes in industrial wine yeast strains. J Appl Micobiol Biotechnol 86:931–945CrossRefGoogle Scholar
  13. 13.
    Govender P, Domingo JL, Bester MC, Pretorius IS, Bauer FF (2008) Controlled expression of the dominant flocculation genes FLO1, FLO5, and FLO11 in Saccharomyces cerevisiae. J Appl Environ Microbiol 74(19):6041–6052CrossRefGoogle Scholar
  14. 14.
    Herrera VE, Axcell BC (1991) Studies on the binding between yeast and a malt polysaccharide that induces heavy yeast flocculation. J Inst Brew 97:367–373Google Scholar
  15. 15.
    Herrera VE, Axcell BC (1991) Induction of premature yeast flocculation by a polysaccharide fraction isolated from malt husk. J Inst Brew 97:359–366Google Scholar
  16. 16.
    Inagaki H, Yamazumi K, Uehara H, Mochzuki K (1994) Determination of fermentation behaviour—malt evaluation system based on the original small scale fermentation test. XXIII European brewery convention symposium. Andernach, Germany, pp 110–136Google Scholar
  17. 17.
    Ishimaru S, Kudo S, Hattan M, Yoshida T, Jun’ichiro Kataoka (1967) Selection of small vessels for fermentation tests in the laboratory. Rept Res Lab Kirin Brewery Co Ltd 10:61–65Google Scholar
  18. 18.
    Jibiki M, Ishibiki T, Yuuki T, Kagami N (2001) Application of polymerase chain reaction to determine the flocculation properties of brewer’s lager yeast. J Am Soc Brew Chem 59(3):107–110Google Scholar
  19. 19.
    Jibiki M, Sasaki K, Kaganami N, Kawatsura K (2006) Application of a newly developed method for estimating the premature yeast flocculation potential of malt samples. J Am Soc Brew Chem 64:79–85Google Scholar
  20. 20.
    Jin YL, Speers RA (1998) Flocculation of Saccharomyces cerevisiae. Food Res Int 31:421–440CrossRefGoogle Scholar
  21. 21.
    Jin YL, Ritcey LL, Speers RA, Dolphin PJ (2001) Effect of cell surface hydrophobicity, charge, and zymolectin density on the flocculation of Saccharomyces cerevisiae. J Am Soc Brew Chem 59:1–9Google Scholar
  22. 22.
    Johnston JR, Reader HP (1983) Genetic control of flocculation. In: Spencer JFT, Spencer DM, Smith ARW (eds) Yeast genetics: fundamental and applied aspects. Springer-Verlag, Berlin, pp 205–224Google Scholar
  23. 23.
    Kaur M, Evans E, Stewart D, Sheehy M, Speers AR, Lake J, Bowman J (2009) Microbial T-RFLP as a solution for premature yeast flocculation (PYF) assurance for malt. In: Proceedings of the 32nd European Brewery Convention Congress, Hamburg, Germany, oral presentation L51Google Scholar
  24. 24.
    Kobayashi O, Hayashi N, Kuroki R, Sone H (1998) Region of FLo1 proteins responsible for sugar recognition. J Bacteriol 180:6503–6510PubMedGoogle Scholar
  25. 25.
    Koizumi H, Ogawa T (2005) Rapid and sensitive method to measure premature yeast flocculation activity in malt. J Am Soc Brew Chem 63(4):147–150Google Scholar
  26. 26.
    Koizumi H (2008) Barley malt polysaccharides inducing premature yeast flocculation and their possible mechanisms. J Am Soc Brew Chem 66(3):137–142Google Scholar
  27. 27.
    Koizumi H (2009) Structural features of barley malt polysaccharides inducing premature yeast flocculation. J Am Soc Brew Chem 67(3):129–134Google Scholar
  28. 28.
    Kryut HR (1952) In: Kryut HR (ed) Colloid science. Elsevier, Amsterdam, pp 1–57Google Scholar
  29. 29.
    Lake JC, Speers AA (2008) Discussion of malt-induced premature yeast flocculation. Tech Q Master Brew Assoc Am 45(3):253–262Google Scholar
  30. 30.
    Lake JC, Speers A, Porter AV, Gill TA (2008) Miniaturizing the fermentation assay: effects of fermentor size and fermentation kinetics on detection of premature yeast flocculation. J Am Soc Brew Chem 66(2):94–102Google Scholar
  31. 31.
    Lawrence S (2006) Brewing yeast cell wall gene expression and function during CO2 induced anaerobiosis. PhD Thesis, Oxford Brookes University, UKGoogle Scholar
  32. 32.
    Lo W, Dranginis AM (1996) FLO11, a yeast gene related to the STA genes, encodes a novel cell surface flocculin. J Bacteriol 178:7144–7151PubMedGoogle Scholar
  33. 33.
    Masy CL, Henquinet A, Mestdagh MM (1992) Flocculation of Saccharomyces cerevisiae: inhibition by sugars. Can J Microbiol 38:1298–1306PubMedCrossRefGoogle Scholar
  34. 34.
    Miki BLA, Poon NH, James AP, Seligy VL (1980) Flocculation is Saccharomyces cerevisiae: mechanism of cell–cell interactions. In: Stewart GG, Rusell I (eds) Current developments in yeast research. Pergamon, Toronto, pp 165–170Google Scholar
  35. 35.
    Miki BLA, Poon NH, James AP, Seligy VL (1982) Possible mechanism for flocculation interactions governed by gene FLO1 in Saccharomyces cerevisiae. J Bacteriol 150:878–889PubMedGoogle Scholar
  36. 36.
    Miki BLA, Poon NH, James AP, Seligy VL (1982) Repression and induction of flocculation interactions in Saccharomyces cerevisiae. J Bacteriol 150:890–899PubMedGoogle Scholar
  37. 37.
    Mill PJ (1964) The nature of interactions between flocculent cells in the flocculation of Saccharomyces cerevisiae. J Gen Microbiol 35:61–68PubMedGoogle Scholar
  38. 38.
    Nakamura Y (2008) The practical hints for brewing from premature yeast flocculation (PYF-positive) malt. Oral presentation O48 at the World Brewing Congress, HonoluluGoogle Scholar
  39. 39.
    Nishihara H, Miyake K, Kageyama Y (2002) Distinctly different characteristics of flocculation in yeast. J Inst Brew 108:187–192Google Scholar
  40. 40.
    Okada T, Yoshizumi H (1970) A lethal toxic substance for brewing yeast in wheat and barley. Part II. Isolation and some properties of toxic principle. J Agr Biol Chem 34(7):1089–1094CrossRefGoogle Scholar
  41. 41.
    Okada T, Yoshizumi H (1973) The mode of action of toxic protein in wheat and barley on brewing yeast. J Agr Biol Chem 37(10):2289–2294CrossRefGoogle Scholar
  42. 42.
    Okada T, Yoshizumi H, Terashima Y (1970) A lethal toxic substance for brewing yeast in wheat and barley. Part I. Assay of toxicity on various grains and sensitivity of various yeast strains. J Agr Biol Chem 34(7):1084–1088CrossRefGoogle Scholar
  43. 43.
    Panteloglou AG, Box WG, Smart KA, Cook DJ (2010) Optimization of a small-scale fermentation test to predict the premature yeast flocculation potential of malts. J Inst Brew 116:413–420Google Scholar
  44. 44.
    Panteloglou AG, Smart KA, Cook DJ (2011) PYF from the perspective of brewing yeast: impacts of nutrient uptake and yeast fermentation characteristics. In: Proceedings of the American Society of Brewing Chemists, Sanibel Island, Florida, oral presentation O17Google Scholar
  45. 45.
    Patel JK, Speers RA, Lake JC (2011) Colloidal examination of worts associated with premature yeast flocculation. J Am Soc Brew Chem. doi: 10.1094/ASBCJ-2011-0225-01 Google Scholar
  46. 46.
    Patelakis SJJ, Ritcey LL, Speers RA (1998) Density of lectin-like receptors in the FLO1 phenotype of Saccharomyces cerevisiae. Lett Appl Microbiol 26:279–282PubMedCrossRefGoogle Scholar
  47. 47.
    Russell I (1995) Yeast. In: Hardwick WA (ed) Handbook of brewing. Marcel Dekker, New York, pp 169–202Google Scholar
  48. 48.
    Russell I, Stewart GG, Reader HP, Johnston JR, Martin PA (1980) Revised nomenclature of genes that control yeast flocculation. J Inst Brew 80:116–121Google Scholar
  49. 49.
    Sampermans S, Mortier J, Soares EV (2005) Flocculation onset in Saccharomyces cerevisiae: the role of nutrients. J Appl Microbiol 98:525–531PubMedCrossRefGoogle Scholar
  50. 50.
    Stanislava G (2010) A review: the role of barley seed pathogenesis-related proteins (PRs) in beer production. J Inst Brew 116(2):111–124CrossRefGoogle Scholar
  51. 51.
    Sieiro C, Reboredo NM, Blanco P, Villa TG (1997) Cloning of a new FLO gene from the flocculating Saccharomyces cerevisiae IMI-8b strain. FEMS Microbiol Lett 146:109–115PubMedCrossRefGoogle Scholar
  52. 52.
    Smart KA (2007) Brewing yeast genomes and genome-wide expression and proteome profiling during fermentation. Yeast 24:993–1013PubMedCrossRefGoogle Scholar
  53. 53.
    Smart KA, Boulton CA, Hinchliffe E, Molzahn S (1995) Effect of physiological stress on the surface properties of brewing yeasts. J Am Soc Brew Chem 53:33–38Google Scholar
  54. 54.
    Smit G, Straver MH, Lugtenberg BJJ, Kijne JW (1992) Flocculence of Saccharomyces cerevisiae cells is induced by nutrient limitation, with cell surface hydrophobicity as a major determinant. J Appl Environ Microbiol 58:3709–3714Google Scholar
  55. 55.
    Soares EV (2010) Flocculation in Saccharomyces cerevisiae: a review. J Appl Microbiol 110:1–18PubMedCrossRefGoogle Scholar
  56. 56.
    Soares EV, Mota M (1996) Flocculation onset, growth phase and genealogical age in Saccharomyces cerevisiae. Can J Microbiol 42:539–547PubMedCrossRefGoogle Scholar
  57. 57.
    Soares EV, Vroman A (2003) Effect of different starvation conditions on the flocculation of Saccharomyces cerevisiae. J Appl Microbiol 95:325–330PubMedCrossRefGoogle Scholar
  58. 58.
    Speers A (2010) Miniature fermentation method. J Am Soc Brew Chem 68(4):231–237Google Scholar
  59. 59.
    Stewart GG, Russell I (1981) Yeast flocculation. In: Brewing science. Academic, New York, pp 61–69Google Scholar
  60. 60.
    Stratford M, Assinder S (1991) Yeast flocculation: Flo1 and NewFlo phenotypes and receptor structure. Yeast 7:559–574PubMedCrossRefGoogle Scholar
  61. 61.
    Stratford M, Brundish HM (1990) Yeast flocculation: cationic inhibition. Yeast 6:77–86CrossRefGoogle Scholar
  62. 62.
    Stratford M, Carter AT (1993) Yeast flocculation: lectin synthesis and activation. Yeast 9:371–378PubMedCrossRefGoogle Scholar
  63. 63.
    Stratford M, Keenan MHJ (1987) Yeast flocculation: kinetics and collision theory. Yeast 3:201–206PubMedCrossRefGoogle Scholar
  64. 64.
    Stratford M, Keenan MHJ (1988) Yeast flocculation: quantification. Yeast 4:107–115PubMedCrossRefGoogle Scholar
  65. 65.
    Stratford M (1992) Yeast flocculation: a new perspective. J Advan Microb Physiol 33:1–72CrossRefGoogle Scholar
  66. 66.
    Stratford M (1989) Yeast flocculation: calcium specificity. Yeast 5:487–496CrossRefGoogle Scholar
  67. 67.
    Stratford M (1992) Yeast flocculation: receptor definition by mnn mutants and concanavalin A. Yeast 8:635–645PubMedCrossRefGoogle Scholar
  68. 68.
    Straver MH (1993) Molecular mechanism of yeast flocculation. PhD Thesis, State University of Leiden, NetherlandsGoogle Scholar
  69. 69.
    Straver MH, Aar PC, van der Smit G, Kijne JW (1993) Determinants of flocculence of brewer’s yeast during fermentation in wort. Yeast 9:527–532PubMedCrossRefGoogle Scholar
  70. 70.
    Straver MH, Smit G, Kijne JW (1994) Purification and partial characterization of a flocculins from brewer’s yeast. J Appl Environ Microbiol 60:2754–2758Google Scholar
  71. 71.
    Sugihara M, Oogane O, Yamauchi S, Imai T, Ogawa Y (2008) Improvement of premature yeast flocculation (PYF) caused by PYF-malt using tannic acid. Oral presentation O50 at the World Brewing Congress, HonoluluGoogle Scholar
  72. 72.
    Taylor NW, Orton WL (1975) Calcium in flocculence of Saccharomyces cerevisiae. J Inst Brew 81:53–57Google Scholar
  73. 73.
    Teunissen AWRH, Steensma HY (1995) Review: the dominant flocculation genes of Saccharomyces cerevisiae constitute a new subtelomeric gene family. Yeast 11:1001–1013PubMedCrossRefGoogle Scholar
  74. 74.
    Van Mulders SE, Ghequire M, Daenen L, Verbelen PJ, Verstrepen KJ, Delvaux FR (2010) Flocculation gene variability in industrial brewer’s yeast strains. J Appl Microbiol Biotechnol 88:1321–1331CrossRefGoogle Scholar
  75. 75.
    Van Nierop SNE, Cameron-Clarke A, Axcell BC (2004) Enzymatic generation of factors from malt responsible for premature yeast flocculation. J Am Soc Brew Chem 62:108–116Google Scholar
  76. 76.
    Van Nierop SNE, Axcell BC, Cantrell IC, Rautenbach M (2008) Optimised quantification of the antiyeast activity of different barley malts towards a lager brewing yeast strain. J Food Microbiol 25:895–901CrossRefGoogle Scholar
  77. 77.
    Van Nierop SNE, Rautenbach M, Axcell BC, Cantrell IC (2006) The impact of microorganisms on barley and malt quality—a review. J Am Soc Brew Chem 64:69–78Google Scholar
  78. 78.
    Verstrepen KJ, Derdelinckx G, Verachtert H, Delvaux FR (2003) Yeast flocculation: what brewers should know. J Appl Microbiol Biotechnol 61:197–205Google Scholar
  79. 79.
    Walker S, Griggs D, Fisher G (2008) Factors that promote premature yeast flocculation condition in malt. Oral presentation O49 at the World Brewing Congress, HonoluluGoogle Scholar

Copyright information

© Society for Industrial Microbiology and Biotechnology 2012

Authors and Affiliations

  • Apostolos G. Panteloglou
    • 1
  • Katherine A. Smart
    • 1
  • David J. Cook
    • 1
    Email author
  1. 1.Brewing Science Section, Division of Food SciencesThe University of NottinghamLeicestershireUK

Personalised recommendations