Storing Essential Oils: How To Retain The Maximum Therapeutic Benefit

One of the great concerns of the aromatherapy practitioner is keeping their essential oils at their best. If one buys a good stock of oils, how should they be kept? The answer is a little complex, requiring diligence and knowledge about each type of oil, and the most protective means by which an oil can be stored. Let’s take a look at the range of possibilities, and how you can most easily care for your stock of precious therapeutic essential oils.

The lifespan of essential oils, if simply left in their bottles in the average home ranges from a few months to almost indefinitely. Over time, certain factors in the environment degrade the natural constituents of certain oils and not others. These environmental factors include: the presence of oxygen (or simply exposure to air), heat, and light. Theoretically, oil left in an open bottle, sitting in the sunlight will then have the shortest lifespan, and a closed bottle — with very little airspace — in a dark, cool cabinet will have the longest. Yet because oils vary so greatly in their natural chemical makeup, this is truly just a generalization.

One terms that’s often used, whose meaning is difficult to pin down is “shelf life”. This term is used by manufacturers to help guide consumers as to how long the oil will be “good” for if kept in the most common conditions: in a closed bottle on an open shelf somewhere in your house. For the advanced practitioner, this term has little meaning however, because with the right storage conditions, even very delicate oils can last a very long time.

Also important to note is what is actually meant by “retaining “maximum therapeutic benefits”. Some oils simply become a little flat or uninteresting in their aroma. You may still find them pleasant, and they won’t be harmful to use in this way. Some oils, when they age, can begin to cause irritation in some portion of the population when applied to the skin. The oils where this has been found via scientific analysis are lavender and tea tree. There may certainly be more; the effect of these oils has been elucidated because they’re so popular. So its really if an oil is being topically applied (or ingested) where one need be concerned about certain oils being affected by aging and their environment.

So lets look at the individual oils. The oils with the shortest shelf lives are always the ones cold-pressed from the rinds of citrus fruit: Grapefruit, lemon, lime, bergamot, mandarin, etc. These oils tend to oxidize fairly rapidly, meaning that they are broken down by oxidative radicals — the same type of molecules we consume anti-oxidants to protect ourselves from. They have not been noted to become harmful as they age, though they do loose that certain “freshness” that’s so appealing about very high quality varieties.

For reasons simply due to the natural chemical makeup of the oil, it is grapefruit essential oil that ages most quickly — often having a shelf life of around six months. This can be extended many, many times by storing the oil in a dark bottle, sealed, with very little air at the top, in the refrigerator. You can see this puts a stop to the potential actions of air, light and heat. The best practice of all is, if you will be using the oil frequently, leave some out in a bottle you will work from, bringing the bottle you’ve got in “cold storage” out as infrequently as possible. This creates a condition where the oil is disturbed the very least over its lifespan.

The floral essential oils have a great range of natural shelf lives. Neroli, the delicate anti-stress, anti-anxiety oil has a shelf life similar to those of the cold pressed citrus oils. At the other end of the spectrum are Jasmine and Rose, which naturally retain their wonderful properties for many years after their extraction. Between these are lavender and ylang ylang, which should be considered for cold storage if not being used in the first few months after purchase.

The essential oils distilled from herbs, grasses and evergreens also have a relatively long shelf life, on the order of one to two years. The spice oils, somewhat overlapping this group, have a shorter life when considering their effervescence. The loss of this very top note of “spicy-ness” will not have a huge effect on certain therapeutic properties; ginger, for example, will still have a strong anti-inflammatory action even if this top note is lost. It’s also important to note that many of these oils are available as “CO2″ distillations, which, according to their manufacturer, have a significantly longer shelf life when compared to the steam distilled varieties.

Then we come to oils that actually improve with age. This group includes the classics of sandalwood and patchouli, and the root oils of vetiver and spikenard. These oils may have a a harsher or greener aspect to them when first distilled, which will smooth out over time. These of course can be stored in any condition you wish, and it may even be beneficial to simply leave them out at room temperature — or even put away at room temperature for some time, to let their value increase!

As you can see, there is truly a very diverse range of natural “durability” of essential oils. Without specific data on each oil, you can go by this rule of thumb: the more lively or fresh and oil is in its optimal state, the more likely it should be carefully stored if you do not intend to use it fairly quickly (within 3 months). The safest long-term storage is in the refrigerator, in a dark glass bottle with as little air in the bottle as possible — and leaving this bottle undisturbed; in a cool, dark cabinet is nearly as effective. Clearly there are many factors involved in keeping your oils at their maximum therapeutic potential, but with a little know-how and understanding, it’s really easy — and rewarding — to do.

For more resources on how to use essential oils and flower essencestherapeutically, visit the Ananda Apothecary.