A laboratory method is reported for the determination of the alcohol yielding capacity of starch-containing distillery raw materials. The starch is inverted with dilute HCl under pressure, after which the material is fermented with yeast at pH 5.4. After distillation, the alcohol is determined pyknometrically. The influence of such factors as amount of yeast was determined experimentally. Analysis of the time curves for the hydrolysis of starch (by paper-chromatographic techniques) in relation to pH showed glucose to be the principal reaction product, with only slight amounts of maltose and higher sugars being formed.