Ethanol/benzyl alcohol mixtures are effective thermal stabilizers for jet fuels above 400 degrees C Ethanol, which itself is only a marginal thermal stabilizer, primarily serves to regenerate benzyl alcohol in situ by reducing benzaldehyde, the reaction product formed by the reaction of benzyl alcohol with the hydrocarbon radicals produced at these temperatures. Accordingly, in the presence of ethanol, less benzyl alcohol is necessary to thermally stabilize hydrocarbon fuels under the same conditions of time and temperature.