Canola oil was being cultivated in the Mediterranean region as early as the 14th century. Back then, it was very bitter, so its main use was as a fuel for oil lamps rather than as a source of food. However, plant breeding has long since banished the bitter erucic acid. As a result, canola oil is nowadays produced in vast amounts in Germany too. Canola covered 1.6 million hectares in 2007. One hectare corresponds to about one and a half soccer fields and supplies around 1,600 liters of biodiesel per harvest. Canola is the ideal plant for German biodiesel. It copes very happily with the German climate and has excellent properties for fuel production. To make the fuel, the oil-bearing canola is milled. The resulting vegetable oil could be used directly as a fuel after milling and filtering. But to work in modern diesel engines, it first needs to be processed. This is done by a process called transesterification, in which the glycerol in the canola oil molecules is replaced with methanol under the influence of heat and a catalyst. The resulting fuel is so similar to diesel from petroleum that modern diesel engines can use it without problems.