What are Essential Oils?

For centuries, aromatic plants have been used for their therapeutic benefits. Aromatherapy is both the art and the science of using plant-derived and naturally extracted aromatic oils to promote physical and psychological well-being.

By definition, essential oils are the aromatic isolates of plant material. Basically, they are the compounds that give plants their distinctive smell. Essential oils can come from just about any plant part, including the leaves, stems, flowers, bark, and roots.

Have you ever squeezed a fresh lavender flower and noticed the aroma left on your hands? Or sliced a fresh orange and noticed the bright, juicy scent? Those are basically the essential oils!

Essential oils can have a wide range of therapeutic benefits and value. Our sense of smell is the only one of our senses linked directly to the emotional control centers of our brain. This means that what we smell can have a direct impact on our emotions! Open up a bottle and inhale deeply. Notice how you respond. Do you like the smell? How does it make you feel? Citrus oils tend to be uplifting and bright. They’re great for creating a happy, cheerful vibe. Peppermint is expansive, crisp, and cooling, and encourages deep breathing. Some essential oils, such as lavender, can be very calming and soothing. Other oils, like tea tree, can be very cleansing and purifying!


We know that we love our essential oils, and that we crave different aromas according to our mood. We also know that they are derived from the plant from which they are named. But how do they get from the plant to the bottle? Well, there are several ways to extract essential oils, including 2 primary methods: Distillation and expression.


Various forms of distillation and extraction have been known and practiced for over 5,000 years; however, the advent of true steam distillation is credited to Avicenna (980-1037), a Persian scholar who wrote the Canon of Medicine documenting plants and their uses.

Essential oils are stored by plants in sacs. During steam distillation, the most common form of distillation of essential oils, plant material is placed inside a sill. Steam or water/steam is pressurized and makes it way through the plant material to remove the volatile components. These rise up through a connecting pipe leading them to a condenser, which cools the vapor and brings it back into liquid form. The water and oil separate, and the water is separated out. The water is called a hydrosol and the oil is the essential oil.


Expression, also referred to as cold-pressing, is the most common method of essential oil extraction for citrus fruits such as grapefruit, lemon, and orange. Most citrus essential oils are actually derived from the fruit’s rind. When you slice an orange, you are cutting open some of the oil sacs, thus the bright, juicy aroma. Try smelling an orange peel before you cut into it, and then notice the change in aroma after the sacs are cut open.

In the past, this expression took place through what is called sponge pressing, which was done by hand. Of course, this is in no way practical for modern-day extraction. Now, modern machinery that uses centrifugal force separates the essential oil from the juice during citrus juice production.

Citrus essential oils can also be extracted through distillation. This can create variances in the aroma of the essential oil being extracted, but there are certain benefits to using this process.

Many cold-pressed/expressed citrus oils contain certain components which can cause photosensitization when used on the skin in the presence of sunlight/ UV rays.

When citrus oils are distilled, these photosensitizing compounds are not present.


Sometimes plant material is just too delicate to withstand the high heat and pressure of distillation. This is true of jasmine flowers, for example.

Solvents can be used to help coax out the aromatic beauty of such fragile botanicals. The result is technically called an absolute. The basic concept is that plant material is macerated and mixed with a solvent like hexane or alcohol. These chemicals attract the essential oil out of the plant material. The oil and the solvent are then separated.

Many aromatherapists do not consider absolutes to be true essential oils and do not recommend them to be used in aromatherapy, as there may be residual solvents left in the aromatic material at the end of processing. However, oils such as jasmine and rose are most often available as absolutes. These oils are quite valuable in aromatherapy for their therapeutic value.

Whichever method is used to extract an essential oil, it is important to know that essential oils are potent and highly concentrated — in fact, you might be surprised just how concentrated they are!

  • 1 lemon produces approximately 5 drops of essential oil
  • 1 pound of peppermint plant material produces about 15 ml of essential oil


With all this plant power inside each drop, many essential oil companies label their oils as Therapeutic Grade. OK, but what does that mean?

First of all, there is no industry standard or regulatory body to define what qualifies an essential oil to be labeled as therapeutic grade, natural, or even pure. Companies can pretty much call anything an essential oil.

In order to attain any therapeutic benefits from essential oils, it is important to use only pure essential oils.

If a healthy plant is grown, harvested, and distilled, the essential oil extracted should contain therapeutic benefits.

Pure therapeutic-grade essential oils should never be diluted with aromatic isolates, lower-cost synthetic aromatic substitutes, or any undisclosed ingredient.

There’s nothing wrong with diluting essential oils in a carrier oil. It is actually responsible and safe essential-oil practice to do so, but it is also important for companies to disclose if anything else is added to the bottle before sale.

To ensure you are investing in a quality essential oil product, it is always best to get to know your supplier. Ask if third-party testing is done to ensure purity. Look for species name and country of origin on the labels. Do your research. Ask questions, have fun, and always keep learning!