On Friday someone who has purchased aromatherapy products from me in the past was in and we got to discussing issues around the shelf life of oils. She was surprised to find out that essential oils do have some limits to their useful life and suggested I post some guidelines on my website. [On a side note – I am always happy to have suggestions for information to blog about or have on the website.]
On to the meat of the issue. Can essential oils last forever? Some say yes, given the right conditions. Their right condition (tightly sealed in a cool, dark place) seem to pretty much preclude use – so, I am going to go with no, essential oils do not last forever. Keep in mind that the time frames I am going to be talking about apply to the therapeutic effectiveness of the oils. If you are only using the oils for scent purposes the whole timeline is different. Either way, some simple precautions can help extend the useful life of your essential oils.
- dark, glass bottles (they eat plastic, which is not good for them or the plastic)
- tightly capped (to keep out oxygen)
- in dim/dark steady temperature environment (cooler is better but fluctuation is the real killer)
- buy good, pure, products
Very simple and straightforward. Basically you need to take into account that these are volatile (yes, they are flammable) oils that, as all oils do, oxidize (change chemical structure in the presence of oxygen). UV is hard on them and high temperatures and sudden changes speed the oxidation process. The above safeguards will ensure that your essential oils last as long as possible.
Within those guidelines there is still a range of life expectancy that varies based to a large extent on how it was prepared and to the actual chemical composition. Most essential oils are steam distilled and have a life span of about 2 years. The conifer (i.e fir, pine) tree oils and tea tree are exceptions as they deteriorate more quickly, around 12-18 months. On the shorter side are cold pressed oils, the citrus oils fall into this group. In fact the citrus oils are the most volatile of the oils and only maintain peak condition for 9-12 months. More viscous oils (rose, thyme, eucalyptus, patchouli) last longer and can actually improve over time. By the way these timelines also echo another aspect of aromatherapy mixing – the idea of top, middle and base note; respectively the scents that dominate the scent first, second and third with the staying power increasing for each.
Some of the products used in essential oils that are actually absolutes (extracted by solvents). These can be very long lived, up to five years and can include: rose, jasmine, vanilla and several other oils.
Given this broad spectrum, noting purchase dates is a wise idea, as is keeping in mind that these dates indicate when the oils begin to become less effective therapeutically – not when they suddenly ‘go bad’. Do not go and throw out your oils the day after they expire, just be aware that the oil is not as potent as it was and that it may be wise to replace it sooner rather than later. If you are only using the oils for their nice smell, feel free to keep on using it until your nose tells you it is time to go. The oils do not become harmful just less useful.
Oils that have changed scent, thickened (compared to time of purchase) or become cloudy are well past their best before date and should be replaced.
Let’s quickly consider dilutions of essential oils. I tend to buy rose oil in a 2% dilution – the $150 price tag for the 100% is very steep and rose is not a favorite of mine. I simply keep in mind that a drop of the oil is 98% base oil and use appropriate amounts. This also means that the 5ml bottle empties quickly, which is good as it will go off much quicker than pure rose oil (i.e. – 9-12 months vs 5+ years). May of the more expensive oils are available in the diluted format, just keep in mind how that changes the parameters of use and you are fine to use them.
The great thing about the oils I order is that both all the essential oils have the method of extraction on the side, along with the scientific name of the plant and the country of origin.
Other places I visited while writing this: quinessense and aromaweb