A high yield method for fermenting carbohydrate to ethanol, comprising a) treating carbohydrate with a composition containing 10-90 wt % of an aldehyde selected from the group consisting of an formaldehyde, para-formaldehyde, glutaraldehyde and mixtures thereof, 1-50 wt % of a surfactant having an I JLB from 4 to 18, 0-20 wt % of an antimicrobial terpene, or essential oils, 1-50 wt % of organic acids selected from C1-24 fatty acids, their salts, and glyceride esters thereof, and 1-50 wt % water, b) fermenting said carbohydrate in the presence of yeast in a fermentation broth, and c) isolating ethanol in a higher yield than would be obtained without step a).
