Plant material is broken down by boiling water or steam, the fluids cool and separate in the condensing coil, the essential oil floats to the top and is siphoned off; the balance is then a hydrosol.
Hydrosols unlike essential oils that must be diluted, contain the plant essence, but are gentler, generally making them suitable for direct skin applications. Often hydrosols are used as astringents, since they hold water-loving acidic elements where bacteria does not fare well
Hydrosols (sometime called Floral Waters) are therapeutic waters created during distillation.