**2.3 Hydrodiffusion**

It involves spraying water vapor through plant material in a top-down position. In this case, the vapor passing through the plant material is downward, as opposed to other traditional distillation techniques (**Figure 3**). This technique is more advantageous, since it qualitatively and quantitatively improves the harvested essential oil, saving time, steam, and energy [18].

**Figure 2.** *Extraction of essential oils by hydrodistillation [16].*
