Essential oils are very useful. They give off pleasant fragrances that can uplift any room. They can also be used for medical purposes.
Making essential oils can be complex. The oil is gathered from various parts of plants. Only a small part of the plant has oil on it so it may take up to a hundred pounds of the plant to make one ounce of the oil. At least the oil is heavily concentrated.
There are multiple ways to extract the oil when making essential oils. Some methods are better than others for specific plants. Usually the harder it is to extract the oil from the plant, the more expensive the oil will be.
The most common method used for making essential oils is steam distillation. In this method high-pressure steam goes over the plant matter, into another chamber, and then until a container. The oil is skimmed off the top and the water underneath it can be used for toners or fragrances.
Now when the flower or plant is too fragile, then solvent or steam diffusion extraction is used. Steam diffusion extraction is similar to steam distillation, but the steam is at atmospheric pressure instead of high pressure. Solvent extraction uses a solvent to extract the oil and then the solvent is removed through low-pressure distillation. A waxy solid is left over which is oils, waxes, and pigments and all of them are then separated out and used.
There are some flowers or plants that have very little essential oils. For these plants the enfleurage method is used. Enfleurage saturates flowers in odorless vegetable oil to extract the oil. Alcohol then removes the essential oil from the vegetable oil and then evaporates over time.
Citrus essential oils come from the fruit of plants rather than the actual plant. The cold pressing method squeezes the fruit until the juices are out. The juice is then centrifuged to separate the oil.
The last method is carbon dioxide extraction. The carbon dioxide is released into a container that has the plant and slowly turns into a liquid. The liquid form of carbon dioxide acts as a solvent and extracts the essential oil. The liquid passes into another chamber and the carbon dioxide evaporates into a gas and leaves the essential oil behind.