In 2006, more than 5 billion gallons of fuel ethanol were produced in the U.S. mostly from corn (> 90%), consuming about 2.15 billion bushels or 20% of the corn harvest. U.S. commercial production of corn ethanol uses either a dry-grinding or a wet grind process, which differ with respect to their complexity, costs, numbers and types of co-products produced, and the flexibility to produce different kinds of primary products. Dry-grind is the most prevalent process and much of the current expansion of the industry uses this technology, but wet milling is used by some facilities. In addition to ethanol, corn gluten meal, corn gluten feed, oil, and carbon dioxide are produced as co-products in the wet mill process. Corn gluten meal and corn gluten feed are used as livestock feed. The oil can be further refined into food-grade corn oil. The carbon dioxide can be captured and used to carbonate beverages or to produce dry ice. Approximately 2.5 gallons of ethanol, 16.4 pounds of carbon dioxide, 2.1 pounds of oil, 2.6 pounds of corn gluten meal, and 11.2 pounds of corn gluten feed are produced per bushel of corn using the wet milling process.