Load the plants into a distillation vessel. This is typically a large, food-grade stainless steel pot used only for distilling lavender. The pot is filled with the lavender plants and sealed.
Introduce low-pressure steam into the bottom of the vessel to boil the essential oil from the plant. Allow the steam to exit through the lid of the vessel and feed it through a condenser. The steam is cooled into a liquid by cold water that runs through coils in the condenser.
Feed the condensate into a separator. This liquid is divided into two parts: lavender water on the bottom and the lighter essential oil on top. The lavender water is drained off through an opening in the separator situated below the level of the essential oil.
5 Collect the essential oil in a beaker on top of the separator.
Found at ehow.com