The use of essential oil dates back thousands of years. Today, the practice has evolved into a multi-billion dollar industry. It’s no wonder it’s so profitable when a 15ml bottle of high-quality pure essential oil can cost anywhere from $8 to over $20!
With that in mind, it’s understandable that you’d want to know – do essential oils evaporate? – to make sure that the big bucks you’ve shelled out for your micro-bottle of essential oil are not literally evaporating into thin air.
What are essential oils?
They are hyped as the cure-all for pretty much anything that ails you. They are used for everything from skincare, stress relief, and as a sleeping aid to treating anxiety, alleviating insomnia, and boosting concentration, just to name a few. They can be inhaled, ingested, or applied directly on the skin, using a humidifier, vaporizer, diffuser, or in a carrier oil.
It seems like everyone is using them!
But how many people actually understand what they are?
Essential oils are concentrated, steam-distilled, or cold-pressed extracts which maintain the characteristic fragrance (or essence) of the plant from which it has been extracted. Essential oils can come from almost any part of a plant, such as the seeds, flowers, fruit, leaves, stems, and roots.
With steam distillation, an essential oil is extracted from the plant, whereby steam is passed through the plant to draw out the oil. The oil is then collected once the steam condenses.
Cold pressing can also be used to extract essential oil through the mechanical action of squeezing or pressing.
Now although they are named “essential” oils, they are not required by the body to function properly (despite how much some people may try to convince you that you can’t live without them). Essential oils should not be confused with other terms like “essential amino acids” or “essential fatty acids”, which are deemed ‘essential’ or nutritionally necessary.
The ‘essential’ in essential oils refers only to the ‘essence’ of the plant from which it is derived.
The medicinal, healing, and fragrance properties of essential oils depend on the specific oil. But all essential oils have similar physical properties. Essential oils are strongly aromatic, colorless liquids at room temperature.
They are lipid-soluble (capable of dissolving in oils) but not water-soluble, and they are extremely volatile.
Do essential oils evaporate?
Simply put; yes essential oils evaporate. As you’ve read above, essential oils are ‘extremely volatile’. The volatility of a material refers to how readily a substance vaporizes or evaporates.
Being extremely volatile means that essential oils evaporate quickly and easily.
There are four factors that affect the speed at which essential oil will evaporate:
- Molecular size – Essential oils from different plants will have a different molecular structure. Those with the larger molecules are heavier and require more energy to evaporate.
- Temperature – The higher the temperature, the faster it will evaporate.
- Surface Area – Because evaporation occurs at the surface of the essential oil liquid, the greater the surface area, the faster it will evaporate. Think of it this way… evaporation will take place faster from a petri dish than it will a test tube, because the petri dish has a much larger surface area.
- Air Circulation – evaporation will occur inside a capped bottle and once the oil vapours saturate the space inside the bottle, there is no room for more evaporation to occur. But if you open the bottle and expose it to air, the increased air circulation will allow the vapour-saturated air in the bottle to escape from the container to make room for more evaporation.
How does evaporation affect essential oil diffusers?
Nebulizers and Diffusers disperse essential oils into the air. The faster the essential oil evaporates, the faster its aroma fades.
This means that the aroma from lighter oils will fade more quickly, while the aroma from heavier oils will last longer.
Light-weight essential oils include grapefruit, lemon, peppermint, lavender, and eucalyptus. These produce what are called top notes, which don’t last very long.
Medium-weight essential oils include ginger, rosemary, geranium, chamomile, and rose. These middle note essential oils will last longer than the top note essential oils.
Heavy-weight essential oils include patchouli, ylang ylang, ginger and sandalwood. These produce what are called bottom notes, and their aromas will linger for a much longer period.
Creating balanced combinations of two different essential oils can help make a scent last longer. For example, combining a top note essential oil, like lemon, with complementary base note essential oil, like ginger, helps stabilize the more volatile top note chemicals, making the lemon essential oil last longer when mixed with the ginger, than diffusing it on its own.
See our article on the top 20 essential oils to get lots of blending ideas!
A diffuser is the most common way to unleash essential oils into the air, but you can use a humidifier, nebulizer, etc.
How do you keep essential oils from evaporating?
Here are some easy ways to minimize the evaporation of your essential oil.
Keep the bottle closed
This should be obvious. The oil that has evaporated inside the essential oil bottles is lost whenever you open the lid. Try not to open your essential oils too often.
Keep the bottle capped
Make sure you cap your bottle of essential oil immediately after use and ensure it’s tightly screwed on when you are not using it.
Keep the bottle cool
Store your essential oil in a cool, dark place. Keep the bottles away from sources of light and heat, which increase the rate of evaporation.
Keep the bottle corked
Do not remove the reducer lid which only allows one drop of oil to come out at a time. This barrier also reduces the amount of essential oil vapor that can escape while the bottle is open.
Keep your oils in small bottles
Transfer your essential oil into smaller containers if you’re buying in bulk. If you have a jerry can of essential oil of which you’ve already used half, remember – your essential oil can only evaporate as much as the pocket of air between the oil and the lid.
The smaller that space, the less evaporation will occur. There is more room to evaporate in a bigger, half-empty jug than in a smaller bottle.
Essential oils are extremely volatile, so they will evaporate quickly. You can minimize evaporation by tightly closing the caps as soon as you are finished using the oil, keeping the reducer lid on the bottle, keeping your essential oils stored in a cool, dark place, using smaller bottles if you are buying in bulk, and opening the bottles as little as possible.