Esterification is a chemical reaction in which an acid (often an organic carboxylic acid) and an alcohol combine to form an ester and water. This process typically involves the removal of a water molecule, which allows the remaining parts of the acid and alcohol molecules to join together. Esterification is a key reaction in organic chemistry and has a wide range of applications, including the production of various esters that are used as flavors, fragrances, and in pharmaceuticals.

In the context of energy commodities trading, esterification is particularly important in the production of biodiesel. This renewable fuel is made through a process called transesterification, which is a specific type of esterification. In this process, vegetable oils or animal fats (which contain fatty acids) react with an alcohol, typically methanol or ethanol, in the presence of a catalyst to form methyl esters or ethyl esters of fatty acids, known as biodiesel, and glycerol.

For more detailed information about esterification, please refer to the following websites:

1. Khan Academy: An educational platform that offers a comprehensive resource on esterification along with tutorials on many other chemistry topics. The section on esters and the process of their formation is especially useful.
https://www.khanacademy.org/science/organic-chemistry/carboxylic-acids-derivatives

2. Britannica: A respected reference resource which provides insight into various chemical reactions, including esterification. Their detailed article on carboxylic acid derivatives discusses the formation of esters from carboxylic acids.
https://www.britannica.com/science/carboxylic-acid/Derivatives-of-carboxylic-acids

Please note that the availability and content on these websites can change; always check to ensure that the information remains current and that the web pages are still active.