The American Society of Testing and Materials (ASTM) has developed E85 fuel specifications to ensure proper starting, operation, and safety. Please refer to the table below for ASTM D5798-99 Standard Specification for Fuel Ethanol for Automotive Spark-Ignition Engines.
This table of minimum commercial standards is also found on page 10 of the Handbook for Handling, Storing, and Dispensing E85 (PDF 3 MB) Download Adobe Reader. Please ensure the fuel delivered to your storage tank is guaranteed by your supplier to meet these standards. Include this spec as a requirement in your supply contract.

E85, like gasoline and diesel fuels, is seasonally adjusted to ensure proper starting and performance in different geographic locations. For example, E85 sold during colder months often contains 70% ethanol and 30% petroleum to produce the necessary vapor pressure for starting in cold temperatures. An E85 fueling site operator typically cannot carry over summer-blend E85, but rather must "blend down" any remaining summer fuel to make an E70 mixture. This may be done with relative ease by adding additional gasoline to the storage tank. There is no concern with carrying over winter-blend E70 into warmer months as flexible fuel vehicles operate on any blend of E85 and gasoline in during warmer times. For retail service stations, seasonal fuel adjustments are handled automatically at the wholesale fuel terminal.

Please refer to the Handbook for Handling, Storing, and Dispensing E85, Table 3 (p. 10) and Appendix A (pg. 22-23), for seasonal blending requirements in your area. In Table 3, the Value of Class refers to the Volatility Class by Month found in Appendix A. We encourage you to provide a copy of this reference guide to your personnel, equipment, or fuel suppliers or any prospective service station that will be working with E85.

N/A = Not applicable