Steam distillation is the most commonly implemented method of essential oil extraction. Simply put, steam distillation of essential oils works by passing hot steam through raw plant materials. The heat from the steam serves to vaporize the plant material’s volatile compounds. The vaporized compounds rise and enter a cooling chamber, known as a condenser unit. As the vapors cool, they’re condensed from steam back into a liquid form. After being condensed, the essential oil and water from the water-soluble parts of the plant—known as hydrosols or floral water—are collected into a receiver with two separate outflows. Because oil and water don’t mix, the essential oil floats above the water. As such, the lower outflow will draw out the water and the upper outflow will draw out the essential oil.