The goal of this study, a collaboration between NREL and CRC, was to examine the quality of 'E85' fuel around the country in each of the three volatility classes identified in ASTM D5798-10. The volatility varies between classes due to drivability requirements as ambient temperature changes, but all other properties are the same in each class. A significant change to the 2010 version of the specification is the reduction of minimum ethanol content to 68 vol% for all classes. Previous versions of the specification required different minimum ethanol content depending on the allowable vapor pressure. Samples were collected from 21 states between July 2010 and May 2011, with almost 40 samples collected in each class. Samples were tested for key properties in D5798-10 to assess fuel quality. The parameters tested were volatility, ethanol content, water content, acidity, pHe, inorganic chloride and sulfate, and total sulfate. Forthcoming changes to D5798-11 include a minimum ethanol content of 51 vol% for all classes. Coupled with this change in ethanol content, a fourth volatility class was added. A future study is recommended to assess how fuel properties may change with these changes in the specification.
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