There’s a lot of varying information about how essential oils should be stored, and what their shelf lives might be. Should you store them in a dark cool place? Refrigerate them? Make sure they all get used in a few months, or don’t worry about it because “pure essential oils” last forever? The truth is, the answer to these questions depends completely on the oil itself. Here’s a quick look at how to care for all your oils, to ensure you receive the maximum therapeutic benefits.
There really is a range of lifespans of therapeutic grade essential oils, the reason being is that some oils are highly susceptible to degradation by environmental factors, while others actually benefit from these factors — with a whole range in between. These factors are simply air, light and heat. So you can see that leaving a bottle open in the sunlight can be the fastest way to age it. Seal this bottle up with very little air in the top, put it in cool storage, and you’ll be aging that same oil very slowly. This “anti-aging” method will work for all oils, but is really only necessary for a very few.
What we’ll refer to as “shelf life” means the time for which the oil will retain the majority of its aromatic and therapeutic potential when stored in common conditions: at room temperature, with the cap on, out of sunlight, but not necessarily in the dark. It’s important to note that even “sensitive” oils stored undisturbed, sealed with as little air in the bottle as possible, in the refrigerator can last significantly longer than the shelf life — almost indefinitely, in-fact.
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 next group of oils to consider are the florals. Interestingly, the essential oil steam distilled from the flower of a citrus tree, neroli, is the most sensitive to degradation as well. Neroli has been noted to simply go flat, and some say its important to not only keep it in a dark, cool place, but not even shake the bottle! Other florals certainly have longer shelf lives, on the order of one to two years. It may be the sweeter floral aromas that oxidize most rapidly: lavender and ylang ylang are examples. Rose otto, on the other hand, can still be wonderful after five years.
We find a wide variation in shelf lives in other oils still. Those steam distilled from spices: black pepper, ginger, cardamom and the like, can quickly loose their spicy top notes. These same oils when found as CO2 extractions are much more resistant to breakdown. Oils from herbs, grasses and evergreen tree needles and leaves are fairly hearty. Generally, when an oil has a bright, lively aspect to it, it is more susceptible to a noticeable change due to improper storage. This freshness can easily be lost when exposed to heat, light and air.
Then there are the oils that actually improve with age. This includes many of the very earthy aromatics: sandalwood, patchouli, vetiver, frankincense and myrrh. Their fresh, top notes when first distilled are considered harsh, and not necessary for their therapeutic activity. Rather, the aromas become smoother and more beneficial with age. These oils of course require no special storage considerations.
This gives you a little idea of the range of possibilities in terms of the aging of essential oils: some degrade quickly and others not at all. In most cases, if you’ll be using your oils within 6 months, there’s little concern about storage storage conditions, except for the most sensitive oils of grapefruit or neroli. When in doubt, do keep your oils in a cool, dark location, and if it will be some time until you use them, refrigeration is not a bad idea. The only caveat there is to be sure not to frequently return the oil to room temperature and then back again. By following these simple guidelines, you’ll be sure to receive the maximum therapeutic benefit from your essential oil collection.
The author is a natural health professional utilizing pure essential oils and therapeutic blends.