Lavender essential oil distillation happens through a process called steam distillation.
For a 60L still about 9-11 kg of freshly cut lavender is required. 9-11 kg of fresh lavender is anywhere from 6-12 full lavender plants depending on the variety, age, and health of the plant. The plant has the most oil content when in full bloom. The lavender is packed into the kettle of the still on top of the steaming tray trying to avoid pockets of air between the lavender. It is ok to pack the still tight, don’t worry about over stuffing the still. We fill the lavender all the way to the top of the pot. Once we have the pot filled up we put the lid of the kettle on and connect the swan neck from the pot to the condenser and turn the heat on under the kettle.
Temperature is monitored throughout this process to insure that the highest grade of oil and hydrosol is obtained. During this process the steam causes the plants oil glands to erupt, and the oil evaporates into the steam. At this point, the steam makes its way to the condenser, which condenses it back to a high grade oil and hydrosol. This process was used in early distillation processes in France. At this point the lavender water and oil are separated into their respective containers, the essential oil, being lighter than water, rises to the surface of the condensate, and is collected in a beaker attached to the separator. This state of the art process produces the highest quality essential oil and hydrosol.
How Essential Oils Are Extracted (youtube.com)