Effect of process conditions on alcohol yield of wheat, maize and other cereals

Abstract

Past research has demonstrated the potential of a range of cereals in the production of grain whisky and ethanol. This paper describes further research that has been carried out to examine the role of processing conditions, the aim being to optimise alcohol yield and reduce processing problems. The first part of this study examined the impact of cooking temperature on alcohol yield and residue viscosity. Results showed that altering the cooking temperature had an effect on predicted spirit yield (PSY) in some, but not all, types of cereal. Hence, in order to obtain the maximum amount of alcohol, cooking regimes should be altered depending on the type of cereal being processed. Altering cooking temperature was also found to have an influence on residue viscosity. High residue viscosity can cause downstream processing problems and is a particular issue when processing wheat. The results of this research demonstrated how such problems could be lessened through changes to the cooking temperature. The second part of this research explored the optimisation of alcohol yield from Kipling, a "poor" quality variety of distilling wheat, through the use of commercial enzymes. A range of enzyme preparations were compared. Results demonstrated that some of these preparations have potential to increase the amount of alcohol that can be obtained from this wheat variety. However, results showed that optimum yields would only be achieved under controlled cooking temperatures. © 2008 The Institute of Brewing & Distilling.