The distillate separates into two layers - essential oil and water. During steam distillation, some thermolabile components of the volatile oil in the plant are destroyed. Solvent extraction techniques usually allow extraction of such thermo-unstable compounds. Solvent-extracted floral aromas are called Absolutes. Solvent extraction of spices yields viscous oily liquids called Oleoresins.
Essential oils are generally mixtures of hydrocarbons and oxygenated compounds.
The odor and taste of volatile oils is determined by these oxygenated constituents which are generally insoluble in water but soluble in alcohol. Any natural oil contains several such compounds which can be separated, identified and measured. A single volatile oil can have multiple applications. Clocimum Ocimum spp. Keora B Pananus odoratissimus Lavender Lavendula spp.