How do I distill lavender oil and what oil recovery should I realistically expect?

Lavender oil is extracted by steam distillation of the flowering spikes, you harvest the spikes at the right flowering stage, load them into a distillation unit, pass steam through, and collect the oil that separates from the condensed water. Oil recovery is low in percentage terms, it takes a large quantity of flowers for a small amount of oil, and the exact recovery depends on variety, stage of harvest, freshness and the still, so treat any recovery figure as a range to verify locally. Harvesting at the correct stage and distilling fresh gives better oil. Many growers do not own a still and instead use a shared community distillation unit, which is often the practical route. Confirm realistic oil recovery for your variety and access to a distillation unit with your aroma mission centre or KVK, since owning a still only pays at sufficient area.