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 formaldehyde, para-formaldehyde, glutaraldhyde 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)
