M-3: The concept of nature–nurture applied to brewer’s yeast and wort fermentation

G. G. STEWART (1); (1) GGStewart Associates, Cardiff, Wales

Yeast, Fermentation, and Microbiology
Thursday, June 5 - 10:00 a.m.-11:45 a.m.
Level 4, Red Lacquer Ballroom

The conflicting approaches of nature versus nurture have been extensively discussed during the past few years, but it is not a novel concept. Nature–nurture concepts were initially introduced by the anthropologist Frances Galton in the book Hereditary Genius, which was published in 1869. Nevertheless, a consideration of nature–nurture concepts is still relevant today, including its application to wort fermentation by brewer’s yeast strains. In this context, nurture refers to the environment experienced by the yeast strain, and nature is the genetic make-up of the yeast. Nature–nurture together is the interaction of the two parameters. A yeast strain will perform differently when pitched in worts of differing composition. Conversely, yeast strains will differentiate when fermenting wort of standard composition. Nature–nurture concepts applied to brewer’s wort fermentations will be discussed with regard to the following parameters: wort sugar uptake, ester formation, wort gravity, and yeast flocculation.

Graham Stewart is an emeritus professor in brewing and distilling at Heriot-Watt University, Edinburgh, Scotland, and visiting professor in bioethanol fermentation at Nottingham University, England. He was director and professor of the International Centre for Brewing and Distilling, Heriot-Watt University, from 1994 to 2007. From 1969 to 1994 he held a number of technical positions with the Labatt Brewing Company in Canada and, from 1986 until 1994, was its technical director. He was president of the Institute of Brewing and Distilling (IBD) in 1999 and 2000. He is also a member of ASBC and MBAA. He holds fellowships in IBD, the Institute of Biology, and the American Academy of Microbiology. He has more than 300 publications (books, patents, review papers, articles, and peer-reviewed papers) to his name. Upon retirement, he established a consulting company, GGStewart Associates, based in Cardiff, Wales. He was awarded the Horace Brown Medal from IBD in 2008, the ASBC Award of Distinction in 2008, the Schwartz Award Lecture in 1976, the MBAA Presidential Award in 1983 and 1998 and Award of Merit in 2009, the Charles Thom Award from the Society of Industrial Microbiology in 1988, and the Alltech Award for Outstanding Service in Brewing and Distilling and Education in 2013; he became a chartered scientist in 2011.

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