To make essential oils various parts of the plant are steam distilled. As the steam pass through the plant material the oil in the plant also vaporizes and combines with the steam. The steam passes through a cooling chamber where it condenses and then collects in a container. The oil, being lighter than water, floats to the top so it can be separated easily. The cooled water is the hydrosol; it has all the water soluble properties of the plant. It is lightly fragrant and gently healing. You can make it at home on your stove if you have a juice cooking pot like the one below. You can use the fresh leaves of plants that you have growing in your garden, or if you have access to some. This stove top method will not be the same as professionally distilled hydrosol because there is no pressure.
This is how you set it up to make juice:
This is how you set it up to make hydrosol: