What distinguishes "sour" crude oil from "sweet" crude oil?

The distinction between "sour" and "sweet" crude oil primarily hinges on their sulfur content. Sour crude oil contains a higher concentration of sulfur, typically greater than 0.5% by weight, which can result in undesirable characteristics for refining. This higher sulfur content makes sour crude less desirable for certain applications and requires additional processing to remove the sulfur during refining, which can increase costs and complexity.

In contrast, sweet crude oil has a lower sulfur concentration, usually below 0.5% by weight, making it more advantageous for refining processes. Sweet crude generally yields a higher quantity of valuable products, such as gasoline and diesel, without the need for extensive desulfurization.

While other factors, such as color, viscosity, temperature stability, and density, may play a role in the characteristics of crude oil, they do not serve as the primary differentiators for categorizing crude oil as sour or sweet. Therefore, sulfur content is the key factor that defines the distinction between the two types.