Similar to beef that you buy in the supermarket, the price of crude varies depending on a number of different factors, one of which is quality. In the case of petroleum, quality refers to how easily the oil can be turned into a “refined” product such as gasoline, diesel, or jet fuel, among others.
Sulfur content of crude oil is the most important indicator of quality. The lower the content, the “sweeter” the oil and the easier it is to refine. Crude with high sulfur content is sometimes referred to as “sour”, and while it is still valuable, it requires more work to remove the impurities and therefore is generally traded at a lower premium.
