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.
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.
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.
It’s also important to consider that its not the end of the world if an essential oil’s aroma gets a little flat. It will still retain much of its therapeutic benefit — if you still like the aroma, wonderful! Inhale it! At the same time, some oils actually cause skin irritation to some people if they’ve gotten old. This has been proven for lavender and tea tree essential oils. Again, they many still impart their therapeutic benefits, but for some people (about 18% of the population) get skin reaction to these oils if they’ve aged too long. The bottom line here is that its still safe to enjoy the aroma of older oils that have theoretically short shelf lives, but its probably better to avoid using them in other ways unless they’ve been stored in a very protective manner.
Looking at the aging of individual oils and groups of oils, it is the cold-pressed citrus oils which oxidize most rapidly. You could even conceive of why this might be: these oils have been directly extracted from fresh fruit, whereas other oils have been steam distilled or solvent extracted. They are the most close to nature as you can come.
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 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.
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.
More on the healing effects of essential oils can be found at http://www.anandaapothecary.com.