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.
To make matters a little more complex, some companies publish a "shelf life" for their products -- and many customers are interested in this figure. This term really only refers to the longevity of an oil after the bottle has been opened and is keep at room temperature and out of sunlight. But by taking measures to prevent an oil's aging, the real shelf life of even the most delicate oils can be many years.
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.
The fastest aromatics to degrade are those cold-pressed from the peels of citrus fruit. You can imagine that while other essential oils have been steam distilled, solvent extracted, or some even distilled with high pressure liquid carbon dioxide, the citrus oils in a way are still in the natural state the fruit had been when they were picked. These oils are very prone to oxidation, a process where oxygen atoms robs other molecules of electrons. The not-so-technical meaning is that the oils go flat, and looses their "zing".
Within the citrus oils themselves, we find that grapefruit essential oil is the most susceptible to oxidation of them all. But it's also important to note that you can easily protect this and all the citrus oils from aging by keeping them in a cold, dark location, in bottles with very little air space in them. The refrigerator is acceptable, though if you choose to keep your oils in the "cold box", consider keeping a smaller bottle at room temperature that you work from, decanting some from the cool bottle once every couple of weeks or so. This prevents the oil in cold storage from being disrupted by frequently changing conditions -- cold to warm to cold again -- and possibly absorbing water from the air in the process.
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.
As for the other end of the spectrum, there are many oils that get better with age, or at least have a shelf life so long as to not be of concern. The "resin" oils are like this: frankincense and myrrh seem to age nicely. Patchouli and sandalwood are two oils that actually command a premium price after they've been put away for storage for several years. Other oils in this category are spikenard, vetiver, and galbanum. So when storing these oils at home, there's really no need to give them special attention at all.
Here you can see the very wide range of correct answers as to how you should properly store your essential oils. The first consideration is whether you'll be using your oils within the first few months after purchase -- if this is the case, there's no need to concern yourself with storage. If you'll be keeping them longer than that, decide how long you'll want to be storing them, and which of those oils falls into the "very delicate" category, the "moderately delicate" category, and the "gets better with age" category. With this knowledge, you can then decide whether to put some of your oils away in cold storage, to maintain their utmost freshness. Through these guidelines, you'll be able to always use oils with the greatest health benefits.
For more on the therapeutic value of pure essential oils, and one of many important oils individually such as geranium essential oil, visit The Ananda Apothecary online.
