Both processes can be used for flavor or essential oil extraction process.

In water distillation or hydrodistillation, elevated pressures is used with plants whose essential oils are difficult to extract at higher temperatures.

In steam distillation, plant material is placed into a steam distillation chamber. Steam is forced into the chamber with it. As the essential oil interacts with the steam, the steam flows into the chilled condensed chamber, turning back into a liquid, providing the essential oil.

You can use fresh plant material as well as dried depends upon types of compounds and plant or its parts-leaves, flowers, fruits, roots etc.

Both processes can be used for flavor or essential oil extraction process.

In water distillation or hydrodistillation, elevated pressures is used with plants whose essential oils are difficult to extract at higher temperatures.

In steam distillation, plant material is placed into a steam distillation chamber. Steam is forced into the chamber with it. As the essential oil interacts with the steam, the steam flows into the chilled condensed chamber, turning back into a liquid, providing the essential oil.

You can use fresh plant material as well as dried depends upon types of compounds and plant or its parts-leaves, flowers, fruits, roots etc.

Mr Joshi, Thanks about your attention.I know that.I want to know different between Water-steam distillation with Steam Distillation. (You said different between water distillation with steam distillation ).

In general, most of the Oils' constituents are high boiling and will decompose under the high heat needed to bring them to a boil. Steam distillation is a much gentler method of achieving the same end. In steam distillation, the distilling pot is infused with steam, which carries the Oil’s vapor into the distilling head and then into the condenser, where the Oil and Water co-condense. As an alternative, steam is generated in situ in the distilling pot

@Robin Joshi 

According to you, we can perform hydrodistillation under reduced pressure to reduce the boiling point of water, is it right?

I have one more question, which method is better for recover essential oil from plant tissues? (quality and quantity also)

Thank you.