E85 gasoline, also known as flex fuel, is a blend of gasoline and ethanol, a type of alcohol made from grains such as corn, sugar cane, or other forms of biomass. The percentage of ethanol in E85 varies depending on geography and season, but it typically ranges from 51% to 83%. E85 is the most common form of flex fuel available on the market.

E85 should only be used in certain vehicles called flex fuel vehicles (FFVs), which have a fuel delivery system and engine designed to use it. Many drivers already own an FFV and do not even know it. To check if a car is an FFV, look for a yellow-colored gas cap, yellow ring around capless fuel fillers, or a flex fuel label on the fuel door. FFVs are capable of running on both ethanol-gasoline blends like E85 and regular gasoline. However, it is NOT recommended to put E85 fuel in any vehicle other than an FFV, as doing so can ruin the engine and void the manufacturer’s warranty.

E85 has some benefits, such as generating more torque and horsepower than gasoline, burning cleaner, and leaving no residue. However, it has some disadvantages to keep in mind, including less energy per gallon, leading to fewer miles per gallon, and limited availability in some regions.