Have you ever wondered exactly what the “light, sweet crude” was referring to when you hear a commodity price quote? Well, it refers to partially refined crude oil. Crude oil (out of the ground) is made up of various components, which can be separated by boiling point (related to the density of a component) – “fractionated”. Lighter fractions are more desireable (such as gasoline and diesel), while heavier fractions contain more sulfur (“sour”). For use, this sulfur needs to be removed, i.e., the oil needs to be made “sweet”). The goal is to go from a “heavy, sour” crude oil to a “light, sweet” crude – i.e. partially fractionated with a higher percent of light components, like diesel, with most of the sulfur gone.