How it's made: Yeast ferments the sugars in corn, sugarcane or other crops into ethanol and carbon dioxide, and the ethanol is then distilled out. Industrial ethanol is also made by adding water to ethylene over a phosphoric acid catalyst.

How it's made: Made by removing water from methanol over an acidic catalyst such as alumina. It can also be made in one step from synthesis gas (carbon monoxide and hydrogen) with a catalyst that first makes methanol and then dehydrates it.