Which property is used to classify oil as sweet, medium sour, or sour?

• A. Sulfur Content
• B. Viscosity
• C. API Gravity
• D. Density

Answer: (A)

Sweetness classification of crude oil is determined by its sulfur content. Low sulfur crude is labeled sweet because it requires less sulfur removal during refining and causes fewer environmental and corrosion issues; higher sulfur crudes are called sour, with medium sour somewhere in between. Sulfur compounds are the main factor that drives the labeling, since they impact refinery processing and emissions. Other properties like viscosity, API gravity, and density describe flow and density but do not define how sulfur-rich the oil is. So sulfur content is the property that sets the sweetness category.