Alert for microbreweries – a case study on unpasteurized and unfiltered beer


  • Karel Fous Research Institute of Brewing and Malting, Lípová 511/15, 120 00 Prague, Czech Republic
  • Anna Jarolímová Research Institute of Brewing and Malting, Lípová 511/15, 120 00 Prague, Czech Republic
  • Petra Kubizniaková Research Institute of Brewing and Malting, Lípová 511/15, 120 00 Prague, Czech Republic
  • Katarína Majtán Research Institute of Brewing and Malting, Lípová 511/15, 120 00 Prague, Czech Republic



storage temperature, yeast autolysis, beer stability


Beer stability, influenced by physical, chemical, and biological factors, poses a considerable challenge for breweries. Biological stability, as a major concern, is effectively managed through practices such as good hygiene, pasteurization, and filtration. Microbiological contamination, often recognizable by increased turbidity or off-flavours, is influenced by temperature, with optimal conditions promoting the growth of specific microorganisms. Lower temperatures slow down flavour changes and chemical reactions in beer, impacting its non-biological stability. This case study explores the impact of storage temperature on autolysis off-flavour development in 10 different unfiltered and unpasteurized beers. The results showed that autolysis off-flavour occurred at both low and higher storage temperatures and that its dependence on the temperature was minimal. This unexpected fact was discovered mainly due to uncovered significant contamination of the commercial beers tested (wild yeasts, lactic acid bacteria, enterococci and coliform bacteria). For this reason, the concentration of cells in the beer appeared as a more influential factor in the development of off-flavours, including autolysis, than the storage temperature. The partial results need to be studied in more detail, nevertheless, we felt it was important to publish the revelation of a strong contamination of beers purchased from regular stores for our experiments. At this point it can already be concluded that the low storage temperature did not help to prevent the development of the contamination and the associated sensory deterioration of the beers.


Aguiar, D., Pereira, A. C., & Marques, J. C. (2022). The Influence of Transport and Storage Conditions on Beer Stability – a Systematic Review. Food and Bioprocess Technology, 15(7), 1477–1494.

Alexandre, H., & Guilloux-Benatier, M. (2006). Yeast autolysis in sparkling wine – a review. Australian Journal of Grape and Wine Research, 12(2), 119–127.–0238.2006.tb00051.x

Axelsson, L. (2004). Lactic Acid Bacteria: Classification and Physiology. In (pp. 1–66).

Baert, J. J., De Clippeleer, J., Hughes, P. S., De Cooman, L., & Aerts, G. (2012). On the Origin of Free and Bound Staling Aldehydes in Beer. Journal of agricultural and food chemistry, 60(46), 11449–11472.

Bamforth, C. W. (1999). Beer haze. Journal of the American Society of Brewing Chemists, 57(3), 81–90.

Boulton, C., & Quain, D. (2001). Brewing Yeast and Fermentation. Blackwell Science Ltd.

Jaskula-Goiris, B., De Causmaecker, B., De Rouck, G., Aerts, G., Paternoster, A., Braet, J., & De Cooman, L. (2019). Influence of transport and storage conditions on beer quality and flavour stability. Journal of the Institute of Brewing, 125(1), 60–68.

Juvonen, R., Virkajärvi, V., Priha, O., & Laitila, A. (2011). Microbiological spoilage and safety risks in non-beer beverages. VTT Tiedotteita-Research Notes, 2599, 107.

Kaneda, H., Kobayashi, N., Furusho, S., Sahara, H., & Koshino, S. (1995). Chemical evaluation of beer flavor stability. Technical Quarterly-Master Brewers Association of the Americas, 32(2), 76–80.

Kubizniaková, P., Brožová, M., Štulíková, K., Vontrobová, E., Hanzalíková, K., & Matoulková, D. (2020). Microbiology of brewing production – bacteria of the order Enterobacterales and culture methods for their detection. Kvasny Prumysl, 66(5), 345–350.

Kulka, D. D. (1953). Yeast Autolysis and the Biological Stability of Beer. Journal of the Institute of Brewing, 59(4), 285–293.–0416.1953.tb02718.x

Liu, C., Shen, Y., Yin, X., Peng, L., & Li, Q. (2014). Influence of Pasteurization and Microfiltration on Beer Aging and Anti-Aging Levels. Journal of the American Society of Brewing Chemists, 72(4), 285–295.

Matoulkova, D., Kopecka, J., & Kubizniakova, P. (2013). Brewing microbiology – wild yeasts and methods of their detection. Kvasny Prumysl, 59(9), 246–257.

Matoulková, D., & Kubizniaková, P. (2015). Lactic acid bacteria and cultivation methods of their detection – Part I. Kvasny Prumysl, 61(3), 76–88.

Paternoster, A., Jaskula-Goiris, B., Buyse, J., Perkisas, T., Springael, J., Braet, J., De Rouck, G., & De Cooman, L. (2020). The relationship between flavour instability, preference and drinkability of fresh and aged beer. Journal of the Institute of Brewing, 126(1), 59–66.

Stewart, G. G. (2004). The Chemistry of Beer Instability. Journal of Chemical Education, 81(7), 963.

Stewart, G. G. (2016). 10 – Beer Shelf Life and Stability. In P. Subramaniam (Ed.), The Stability and Shelf Life of Food (Second Edition) (pp. 293–309). Woodhead Publishing.–1

Suzuki, K. (2015). Gram-positive spoilage bacteria in brewing. In (pp. 141–173).–1

Vaughan, A., O’Sullivan, T., & Van Sinderen, D. (2005). Enhancing the Microbiological Stability of Malt and Beer – A Review. Journal of the Institute of Brewing, 111(4), 355–371.–0416.2005.tb00221.x

Vosti, D. C., & Joslyn, M. A. (1954). Autolysis of baker’s yeast. Applied Microbiology, 2(2), 70–78.–78.1954

Wang, J.-j., Xu, W.-n., Li, X. e., Li, J., & Li, Q. (2014). Absence of fks1p in lager brewing yeast results in aberrant cell wall composition and improved beer flavor stability. World Journal of Microbiology and Biotechnology, 30(6), 1901–1908.

Xu, W., Wang, J., & Li, Q. (2014). Microarray studies on lager brewer’s yeasts reveal cell status in the process of autolysis. FEMS Yeast Research, 14(5), 714–728.–1364.12156

Illustrative image (sources: pixabay photos; graphs - authors)




How to Cite

Fous, K., Jarolímová, A., Kubizniaková, P., & Majtán, K. (2024). Alert for microbreweries – a case study on unpasteurized and unfiltered beer. KVASNY PRUMYSL, 70(2), 888-894.
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