Further Studies on Furfural: The Influence of Raw Materials, Processing Conditions, and Pasteurization Temperatures

In a previous publication from these laboratories (2), evidence was presented that furfural levels in beer increased significantly during shelf-storage, and that increases in furfural levels usually paralleled adverse flavor changes. This paper describes the changes in furfural concentration during the brewing process, the effect of pasteurization and storage, and the influence of grains bill composition on furfural levels. A series of pilot brews was made, samples were collected at each stage of the brewing process, and the quantity of furfural in these samples was measured. It was found that furfural forms in appreciable amounts during mashing and kettle boil, disappears during fermentation, but reappears during storage and aging in the package.