How Is Citronella Extracted?

How Is Citronella Extracted? The extraction of oil from citronella has been done by different processes such as fractional distillation, steam distillation and hydro-distillation (Clevenger’s apparatus) and through supercritical fluid equipments. Which method is used for extraction of oil from citronella? Hydro-distillation and steam distillation are the most common or conventional methods for extracting oil