Steam extraction is where the plant material sits above the boiler in a basket and water is heated below the plant material so the vapor rises up through the plant material removing essential oils. This is very forgiving way to extract plant oils from an essential oil distiller. The hot steam vapor collects oils as it passes through the plant material then the vapor condenses back to a liquid and then can separated. There will be hydrosol and a layer of essential oils.
How to distill essential oils: the 7 basic steps to steam distillation:
Step 1 – Steam is created from boiling water
Step 2 – Passing through plant biomass, the steam breaks up the plant micro particles.
Step 3 – Separating the volatile from non-volatile organic compounds, both rise with the steam.
Step 4 – A condenser cools the steam, which is transformed back to water.
Step 5 – In a separator, the volatile principles (i.e. “essential oils”) rise to the top and are extracted.
Step 6 – The remaining water contains non-volatile principles known as floral waters (i.e. “hydrosols”) that are useful for body care products and contain subtle medicinal properties.
Step 7 – The essential oils are tested for purity and sold on the market.