For regular pump gas,10-15% ethanol, a tanker truck pulls up with no ethanol gasoline(regular,mid,premium) and they fill the tanker with the amount of ethanol to formulate the alcohol percentage. That can get iffy when you watch it happen. With e85 its the opposite. There are irregularities with modern gasoline in general. Works for ethanol too. While the ethanol transfer tank is 1/2,1/3,1/4 full and the weather changes you have variables. Before you fill your 5 gallon(empty pails), rinse the pail with premium unleaded or your chemical grade ethanol and swirl and shake it well. Your just trying to have the gasoline to absorb and moisture that may be in the container. Then dump it. Then pump your e85 and iron ball the cap. Check your O rings if applicable. Should try this also with your fuel cell and just run the tank dry. Many people do none of this and have no issues(its a mind set). Take this info and apply it to what makes you content. For what its worth, I've taken race gas directly from the drum at the race track and watch it fail the fuel check. Sunoco and VP, what????