Production of Grain Whisky and Ethanol from Wheat, Maize and Other Cereals
R.C. Agu1,2, T.A. Bringhurst1 and J.M. Brosnan1
1 The Scotch Whisky Research Institute, The Robertson Trust Building, Research Park North, Riccarton, Edinburgh, EH14 4AP.
2 Corresponding author. E-mail: reginald.agu@swri.co.uk
J. Inst. Brew. 112(4), 314–323, 2006 | VIEW ARTICLE
ABSTRACT
Wheat replaced maize as the main cereal raw material for Scotch grain whisky production 20 years ago. However, other cereals might also have potential for use in grain distilleries and ethanol production. Studies of the properties of wheat, maize, sorghum and millet, showed that they had good potential for grain distilling and ethanol production at comparable nitrogen levels, and had physiological processing characteristics within the range accepted for wheat or maize. Rapid-Visco Analysis (RVA) studies of low and high nitrogen wheat confirmed that, as well as influencing the amount of alcohol produced, the total nitrogen content of the grain had a strong influence on its processing characteristics. In contrast, the alcohol yield potential of maize, sorghum and millet appeared to be largely unaffected by the grain nitrogen levels. The study shows that, while it is possible for wheat to produce similar alcohol levels to those previously associated with maize, cereals other than wheat can potentially be used without detriment to alcohol yield or processing performance. These could be possible long term alternatives, if the economic viability of wheat was to change. The extracted cereal starches also showed significant differences from the original cereals, which had important implications for successful processing, both in terms of cereal selection as well as cooking and fermentation performance.
Key words:
Ethanol, grain whisky, maize, millet, sorghum, starch, wheat.
Publication no. G-2006-1308-464 ©2006 The Institute & Guild of Brewing