sweet and sour crude oil? I certainly did not... until now.
Sweet crude oil is the form of petroleum that oil refineries prefer because it contains exceptionally high amounts of the chemicals needed to produce gasoline, kerosene, and high-quality crude oil.
“Sweet” is a description of how much sulphur is in the oil. In the 19th century, oil workers would taste and smell small amount of oil to determine its quality. Crude oil with low sulphur content had a mildly sweet taste and pleasant smell. (Regardless, I wouldn't be brave to try myself...) Today, oil workers can measure the sulphur content of an oil sample and it is classified as sweet if it contains less than 0.5% sulphur.
We have been using sweet crude oil for at least 4,000 years. Herodotus, an ancient Greek historian, reported that asphalt, which is extracted from crude oil, was used to build the walls of Babylon and it has been used throughout the world since that time. However, it wasn’t until the invention of the internal combustion engine, that the demand for sweet crude oil exploded.
Sweet crude oil is refined to make gasoline, kerosene, jet fuel, and heating oil. Because of the high demand for it around the world, the price of it is very sensitive to economic changes. In 1946, unrefined sweet crude oil sold for $1.69 per barrel, which would approximately $17.00 when adjusted for inflation. Today it reached $113.57 per barrel and the price is keep rising! (A barrel of oil contains 42 U.S. gallons.)
So long my friends,