Steam distillation is the most suitable way to extract essential oil from lavender or lavandin. The water vapour produced by a generator is forced through the plants - and thus the glands - drawing off the essences in the process. This steam, thus loaded with the precious molecules, is then cooled and returned to the liquid state. The mixture of water and essential oil is collected in the "essencier" where the two elements decant and separate due to their different densities - the essential oil is lighter and rises to the top, floating above the aromatic water.This procedure was inherited from the Arab world and is the most widely used. It has undergone some technical improvements, but in essence has remained unchanged since its inception.