Ethanol has an octane rating of 118, the highest of any organic fuel. It is also a pure chemical, so the entire volume of fuel has the same flash point and flame speed. Ethanol burns more completely, cleanly, and at a slightly cooler temperature than normal gasoline, which is a cocktail of different hydrocarbons with slightly different flash points and flame speeds. This means longer spark plug life and fewer carbon deposits in most engines that burn ethanol.

Research results and experience with 10% ethanol-blended gasoline have shown that actual fuel efficiency is essentially identical to that of regular (ethanol-free) gasoline. Yet ethanol contains less caloric energy than gasoline, which should, theoretically, result in poorer fuel efficiency. The discrepancy results from the greater efficiency with which ethanol-blended gasoline is burned during engine operation. This comes from the higher octane rating, and the more consistent flash point for the fuel.