The Release of Fatty Acids as a Consequence of Yeast Autolysis. Ernest C.-H. Chen, A. M. Jamieson, and G. Van Gheluwe, Research and Development Department, Molson Breweries of Canada, Ltd., Montreal, Quebec, Canada H2L 2R5.. J. Am. Soc. Brew. Chem. 38:0013, 1980.

The possibility that free fatty acids (C₆-C₂₄) are excreted during the course of yeast autolysis was studied. Lager yeast was suspended in 0.1 M citrate buffer, and autolysis was induced by heat, alteration of pH, and treatments with ethanol and other organic solvents. The fatty acids released in the media were extracted with chloroform/methanol (3:1), methylated, and then analyzed by high performance gas-liquid chromatography. Results indicated that varying amounts of fatty acids were released, depending upon the conditions under which the autolysis was initiated. The most prominent fatty acids released in the autolyzate were octanoic and decanoic acids, which are two of the main contributors to the "caprylic" (also called "yeast, fatty") flavor of beer. Under normal conditions, fatty acid contents of beer in primary storage do not change appreciably. However, when storage temperature increases, or when contact between the beer and relatively large amounts of yeast cells is prolonged, autolysis may occur, with fatty acids being released as a consequence.

Keywords: Autolysis, Autolysis induction, Fatty acids, Yeast excretion