This paper reports a full evaporation (FE) headspace gas chromatographic (GC) method for rapid determination of ethanol in fermentation liquor. The data show that ethanol in the fermentation liquor was transferred to the vapor phase (headspace) almost completely within 3 min at a temperature of 105 degrees C when a very small volume (< 50 microL) of sample was directly added to a sealed headspace sample vial (20 mL). The ethanol in the vapor phase was then measured by headspace GC using a flame ionization detector. The results show that the present method has an excellent measurement precision (RSD=1.62%) and accuracy (recovery=98.1 (+/-1.76%)) for the ethanol quantification in fermentation liquors. The method requires no sample pretreatment and is very simple and rapid.