Malt Sterilization, Cathode Radiation as a Means of Sterilizing Distiller's Barley Malt

Abstract

Cathode radiation was investigated as a means of sterilizing barley malt for use in converting distillery grain mashes. Irradiation dosages were varied from 0.05 to 2.0 X 10' rep. The resulting malts were examined for viable bacteria and residual a-amylase and were evaluated in laboratory scale grain alcohol fermentations. Irradiation dosages of 0.5 X lo6 rep and above reduced the bacterial counts to less than 2% of those present in the untreated malts.An elevated temperature and prior grinding of the samples accelerated the death rate of bacterial contaminants. A dosage of 0.2 X 1 O6 rep did not appreciably affect &-amylase content nor yield of alcohol, but greatly lowered lactic-type flora developing in the mash during fermentation. While "cleaner" fermentations were obtained with cathodeirradiated malts, this method is not now considered commercially practical.