The interesterification process is one of the oil modification processes the refiner can use to alter the physical properties of oils and fats, The reaction requires a catalyst to proceed. This can be a base or a lipase enzyme. In the currently accepted mechanism of the base‐catalysed interesterification reaction, two anionic intermediates are involved: the enolate anion and the glycerolate anion. The presence of the enolate anion explains why an equivalent amount of FAMEs are formed when sodium methanolate is added to oil and why FFAs are formed when the catalysts is inactivated with water. Based on this insight, process development can aim at avoiding these by‐products and thereby increase the cost advantage of the chemical process over the enzymatic process even further. The chemical process is also more flexible than the solely continuous enzymatic process, which latter requires extensive purification of the oil to be interesterified.