The present invention relates to a granular starch hydrolyzing enzyme composition comprising an acid stable alpha amylase (asAA) having granular starch hydrolyzing activity. The invention also relates to a one-step method for producing an alcohol which comprises contacting a granular starch substrate with an acid-stable alpha amylase (asAA) having granular starch hydrolyzing (GSH) activity and a glucoamylase (GA) in a fermentation step which also comprises ethanologenic microorganisms at a temperature of 25-40 C. to obtain a fermentation broth having 5 to 20% ethanol.