October 21st, 2026

Most of the fuel in E85 is ethanol. In the U.S., nearly all fuel ethanol comes from the starch in corn kernels – but not the corn kernels you eat.

How corn becomes ethanol

Most U.S. ethanol plants use a process called dry milling:

1. Grind: The plant grinds corn into flour.
2. Cook: Water and enzymes break down the starch into sugars.
3. Ferment: Yeast converts the sugars into ethanol.
4. Distill: The plant separates and purifies the ethanol.

Fuel suppliers then transport the ethanol and blend it with gasoline to make fuels such as E10 and E85.

What happens to the rest of the corn?

The parts of the kernel that do not become ethanol are used to make distillers grains, a livestock feed. Ethanol production also generates carbon dioxide during fermentation, which some plants capture for other uses.

Corn is the main source of U.S. fuel ethanol, although producers can also make it from materials such as crop residues and wood. Once ethanol is blended into E85, the finished fuel is delivered to stations for use in flex fuel vehicles. Read How E85 Reaches the Pump for the next part of that process.