Essential oil exist in the roots, stems, leaves, flowers, fruits and seeds of aromatic plants. And according to plant species, essential oil exists in different parts.
The factors that affect the quality and yield of essential oils are as follows:
Same kind of aromatic plants, not same variety
The environment of aromatic plants to grow up
The season, time, and standard of collection
Selection of collection parts
Selection of refining methods
The method and environment for the storage of raw materials