Essential oils are aromatic, volatile liquids obtained from plant material through steam distillation and named after the plant from which they are derived. Essential oils can be defined as either products or mixtures of fragrant substances or as mixtures of fragrant and odorless substances. These fragrant substances are chemically pure compounds that are volatile under normal conditions. Essential oils vary greatly, sometimes due to genetic causes, but also because of climate,rainfall, or geographic origin.
The applications of essential oils are diverse. Widely used in cosmetics and perfumes, they also have medicinal applications due to their therapeutic properties as well as agro-alimentary uses because of their antimicrobial and antioxidant effects.
Steam Distillation - The plant material (called the ‘charge’) is placed in a still and then hot steam is passed through it. The heat breaks open the essential oil storage chambers within the charge, releasing the oil into the steam (remember, essential oils are volatile). The steam/oil rise to the top of the still where they enter a condenser – basically, a long spiral pipe surrounded by cold water - which condenses the steam back into its water form. At the end of the condenser, the water and essential oil are collected in a receiver, usually called a ‘Florentine flask’. This specially designed container has two outflows in view of the fact that oil and water don’t mix, i.e. the solution separates into essential oil and hydrolat. Essential oils are usually lighter than water and so will float above it.