The 4th Brewing Yeast Fermentation Performance Congress, Oxford, England, 9-12 September, 2003.

Abstract

Hot topics brewing in Oxford…… The taste, texture and aroma of beer are primarily dictated by the performance of yeast during the fermentation process. In turn, many factors affect brewing yeast physiology and can have an adverse impact on beer quality – for example: malt wort composition, ethanol toxicity, cold stress/heat shock, osmostress, hydrostatic and CO2 pressure, reactive oxygen species and cellular ageing. An understanding of such factors may lead to better quality control of brewing yeast cultures and, consequently, more efficient and consistent fermentation in breweries. In essence, good yeast fermentation performance equates to good beer! This was the fourth in a series of biennial congresses held in Oxford on the subject of brewing yeast, and brought together around 50 yeast scientists and brewers from Europe and overseas (including Japan, Canada, Brazil, USA, S. Africa and Australia). The general theme, as in previous congresses, was fermentation performance of brewing yeast. This relates to the following desirable yeast attributes: good (but not extensive) yeast growth, efficient conversion of malt sugars to ethanol, CO2 and secondary fermentation metabolites, maintenance of high yeast viability, genetic stability of industrial yeast strains, and correct yeast flocculation characteristics. Understanding and, more importantly, controlling these aspects are central to the success of many yeast-based industries, not just beer brewing. Three days of the conference covered several topics (in lectures and posters) of direct relevance to brewing yeast practice: genomes/strain identification, culture handling, nutrition, stress, fermentation (progress/monitoring), and petite mutations, presented in six technical sessions: Greg Casey (Coors Brewing Ltd., USA) kick-started the meeting by reviewing methods for brewing-yeast strain differentiation. The assessment of yeast culture purity and genetic stability was viewed by Greg to be crucial in modern large-scale breweries that may be handling several strains at a time (e.g. for contract brewing). Chromosome …