The Horace Brown Medal Lecture: Forty Years of Brewing Research

Graham G. Stewart^1,2
¹ International Centre for Brewing and Distilling, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, Scotland.
² Present address: G.G. Stewart Associates, Brook House, Caerphilly Business Park, Caerphilly, Wales, CF83 3GS.
Corresponding author. E-Mail: ProfGGStewart@aol.com
This lecture was presented at the IBD Africa Section Convention, March 2, 2009.

J. Inst. Brew. 115(1), 3–29, 2009 | VIEW ARTICLE

ABSTRACT
Horace Brown spent fifty years conducting brewing research in Burton-on-Trent, Dublin and London. His contributions were remarkable and his focus was to solve practical brewing problems by employing and developing fundamental scientific principles. He studied all aspects of the brewing process including raw materials, wort preparation, fermentation, yeast and beer stability. As a number of previous presenters of the Horace Brown Lecture have discussed Brown’s achievements in detail, the focus of this paper is a review of the brewing research that has been conducted by the author and his colleagues during the past forty years. Similar to Horace Brown, fundamental research has been employed to solve brewing problems. Research studies that are discussed in this review paper include reasons for premature flocculation of ale strains resulting in wort underattenuation including mechanisms of co-flocculation and pure strain flocculation, storage procedures for yeast cultures prior to propagation, studies on the genetic manipulation of brewer’s yeast strains with an emphasis on the FLO1 gene, spheroplast fusion and the respiratory deficient (petite) mutation, the uptake and metabolism of wort sugars and amino acids, the influence of wort density on fermentation characteristics and beer flavour and stability, and finally, the contribution that high gravity brewing has on brewing capacity, fermentation efficiency and beer quality and stability.

Key words:
Co-flocculation, flavour, flocculation, genetic manipulation, high gravity brewing, petite mutation, propagation, stability, wort clarity and composition, yeast management.