Essential Oils: What Are Essential Oils?

What Are Essential Oils?

Essential oils are concentrated plant essences extracted from plant material such as bark, twigs, leaves, petals, fruits, resins, rinds, rhizomes, roots, seeds, stalks, and stems. They are what give a plant its aroma. Many in the aromatherapy tradition describe them as the "life force" of the plant, since they're part of the plant's natural defense system — helping it resist pests, prevent infection, and support its own growth and regeneration.

When essential oils are inhaled or applied to the skin, many people believe they carry some of these same properties into the body. Because this "life force" is highly concentrated and volatile, it evaporates quickly when exposed to air — which is why essential oils are always stored in dark, airtight glass containers.

Essential oils are also remarkably potent. Depending on the plant, a single drop can represent anywhere from a fraction of an ounce to several ounces of the original plant material — some sources describe this as being equivalent to many cups of herbal tea, though that comparison varies quite a bit depending on the source and the specific oil. Because of how concentrated they are, essential oils should always be used thoughtfully and with care.

Blends vs. Singles

Each essential oil is made up of a complex mixture of chemical components — anywhere from a couple dozen to over a hundred, depending on the plant, with some of the more complex oils containing even more. Each plant carries its own unique combination of properties that can support healing, repel pests, uplift the mood, and more. When two or more essential oils are mixed together for a specific purpose, it's referred to as a blend. Many in the aromatherapy community find blends can work more effectively than a single oil on its own, since a blend draws on the combined properties of each oil it contains, and may be gentler than using stronger oils individually. Some oils are also known to enhance the properties of others when blended — cinnamon and myrrh, for example.

There are many essential oil companies that offer pre-blended formulas ready to purchase, or you can try your hand at blending yourself. You can also layer oils one on top of another to reach your desired results.

Extracting Essential Oils from the Plant

There are several ways to extract essential oils from plant material, and the right method depends on the type of material, the structure of the plant, and how much essential oil it contains. Not all plants produce essential oil — in fact, very few plants do compared to the entire plant kingdom. Here's a quick breakdown of the most common extraction method.

Steam Distillation

This is the most common method of extracting essential oils, and you can see the diagram below for how it works. Steam is pushed through the plant material, collecting the essential oil as it goes. As the steam cools and condenses, the essential oil floats to the top of the water and is strained off, leaving behind a hydrosol (or flower water) — which is also medicinal, though far less potent. Timing matters a great deal with this method: the plant must be harvested at the right time, season, and conditions for the most potent oil, and the water must be heated at just the right temperature — too little and the oil won't release, too much and it can be damaged or burned. For this reason, essential oils vary from batch to batch, and not all "pure" oils are created equal. The same plant material can also be steam distilled a second, third, or even fourth time, though later distillations are typically less potent than the first and aren't usually noted on the bottle you purchase. As with most things, you generally get what you pay for.

Cold Pressing

This method is used mainly for citrus oils. The peel is punctured to release the essential oil, then pressed to extract it fully. The juice and essential oil are separated through centrifugation.

CO2 Extraction

A newer extraction method that uses carbon dioxide. Under high pressure, CO2 turns to liquid and acts as a solvent to pull the essence from the plant. Once the pressure is released, the CO2 returns to a gas, leaving the essential oil behind with no residue — unlike solvent-based methods.

Solvent Extraction

This method uses a chemical solvent to saturate the plant material and draw out the essential oil, which is then dissolved in alcohol to separate it from the solvent. Once the alcohol evaporates, the essential oil remains. Because the solvent can't be fully removed, this method typically leaves a small amount of residue behind.

Maceration

Maceration involves steeping plant material in a warm carrier oil for an extended period, allowing the oil to absorb the plant's aromatic properties. It's worth noting that what results from maceration is technically an infused oil rather than a true essential oil, since the volatile compounds don't transfer the same way they do through distillation.

Enfleurage

Enfleurage is a related but distinct, older method used for delicate blossoms with very little essential oil content — ones that would be damaged by heat. Fresh petals are laid on a thin layer of fat (traditionally lard) at room temperature, absorbing the plant's aromatic compounds over time. Spent blossoms are continually replaced with fresh ones until enough has been captured, and alcohol is used at the end to separate the aromatic compounds from the fat. This method is extremely labor- and material-intensive, which shows up in the price of oils produced this way.

Storage and Shelf Life

Because essential oils are volatile and evaporate easily, they should be stored in dark glass containers with a dropper top. Make it a habit to screw the lid back on tightly each time you use an oil — extended air exposure will cause it to lose potency. Store oils in a cool, dark location, away from electrical appliances.

If you add essential oils to a carrier oil, salve, lotion, or other product, that oil will begin to break down and won't stay as potent as it would fresh from the bottle.

Essential oils can generally tolerate higher temperatures as long as they're given time to cool to room temperature before the lid is removed. Citrus oils are the exception — they're especially heat- and light-sensitive, so it's best to keep them out of hot environments.

Many books cite a shelf life of 1–5 years for essential oils, though much of that guidance comes from older sources written before more recent research was available. Properly stored oils can often last well beyond that. My first essential oil was one my husband brought back from Germany when he was 19 — over 20 years ago now — and it's still just as potent and aromatic today as it was when I began using it years later.

What Brand of Essential Oils Should I Use?

Over the years I've tried many different essential oil brands, and I've settled into mainly using one trusted source, though I don't think there's anything wrong with branching out or trying others along the way. That said, I've learned the hard way that not every oil on the market is what it claims to be — so here's what I look for in a company to help you avoid the same lesson.

The first thing to look at is whether a company's oils are truly pure. Because there aren't set industry rules or regulations around essential oils, this can be tricky — the alternative healthcare space has its share of people cutting corners for the sake of profit. Some products are watered down with carrier oil, and in the worst cases, laced with synthetic fragrance — turning something meant to be whole and healing into something closer to toxic.

Beyond the oil itself, I look at the company as a whole.

• Do they run their business with honesty and integrity?

• Do they care about sustainable, organic growing practices?

• Do they truly understand herbs and natural healing, or are they just riding a trend?

• In short — is their bottom line profit, or people?

The brand I've come to trust and recommend is REVIVE. They meet the criteria above plus offer good pricing and free shipping. They are one of the few that use first distillations when available, which tend to be the most potent and pure batch of an oil and best of all they sell directly to customers rather than through a distributor/recruitment model, keeping the focus on the product itself rather than on building a sales network. 

Don't be afraid to ask questions and do a little research of your own — it's okay to try an oil here and there and see how it works for you. And above all, be prayerful about your decision.