AROMATHERAPY - Chapter VII Storage & Life Span of Essential Oils by Deborah Dolen

Excerpt How to Make Perfume and Aromatherapy Basics Copyright © Deborah Dolen 2011 This e-book is available in full version on Amazon Kindle and Barnes and Noble Nook. By Deborah Dolen Mabel White


Like a fine wine, some oils get better with age! These include clove, rose, patchouli, sandalwood, spikenard, myrrh and vetivert improve as they age, but others, notably the citrus oils, oxidize and can become irritating and toxic with age.

Vetivert, I've had for several years, has a gorgeous deep sandalwood scent. At the time of this writing, Sandalwood is $1,500 a pound and Vetivert $100 a pound. Essential oils high in antioxidants, such as carrot and black cumin--should also last for many years. Fading is the only affect I have noticed over many years. Some essential oils are more delicate than others. Lemon and clary sage seem to fade a little after a year, but lavender, tea tree, and clove for instance seem to hang in for two or three.

Most important to the life span of essential oils is the quality you buy in the first place, and then how you store it. Tightly sealed dark glass bottles stored in a cool dark place. Metal bottles, I really like--do tend to corrode inside after 3 years. I am sent professional grade metal containers that are treated and do not do that. Glass is the ideal vessel as it does not absorb the oils. Plastic is not going to work unless it is a non-petrochemical composition and there is one I like and used only for small amounts. Essential oils when stored in fully topped up, tightly sealed, light impervious containers in a cool place 68 degrees Fahrenheit (under 20 degrees Centigrade), preferably under nitrogen, can last from 6 months to 2 years.

Oxygen degrades oils - causing some to lose beneficial properties and causing some constituents to become irritants or sensitizers (especially citrus & conifer oils), so keep bottles tightly closed and out of direct light. It may be advisable to rebottle to smaller bottles as oil is used to minimize the headspace (thereby minimizing contact with oxygen).

Bottles do not need to be colored or dark, that is more of a myth. What color is your bottle? Unfortunately many people have succumbed to the fear mongering and propaganda put forth by the makers of colored glass when it comes to storing essential oils. The amber glass makers will tell you that amber is best, the green glass makers will tell you that green is best, etc. The truth is that most essential oils are photochemically inactive in the visible region and reactive in the ultra-violet (UV) region of the electromagnetic spectrum. Since UV light of high enough energy to cause photochemical reactions in most organic molecules is absorbed (not transmitted) by normal glass, regardless of color, it makes no difference if the oils are in brown, blue, green, purple or whatever color glass. Of course there are a few exceptions, like with the chamazulene containing oils (blue chamomile, blue yarrow, blue tansy, etc.) that you would not want to store in colorless bottles for long periods under heavy lighting conditions. This is because chamazulene has strong absorption in the VISIBLE region of the spectrum (thus the intense dark blue color of these oils) and so it is the lower energy visible light and not just UV light that can significantly effect these oils. But even so, thermal degradation and reaction with oxygen are the biggest enemies of these blue oils, which is why all of our chamazulene containing oils are refrigerated and stored under nitrogen, maintaining the nice dark blue color when you receive your shipment (many times you will find that other suppliers selling these oils will ship them after they have turned dark green due to oxidation from improper storage).

I know many people will still believe they have to keep their oils in drab brown bottles, even after reading this, but I can tell you that based on the research I have done and famous chemists I hang with, it makes no difference what color the bottle is for most the oils. You can extend the life of your oils with ROE, Rosemary Oleoresin extract--which is not to be confused with Rosemary Essential Oil. ROE slows down the oxidation process dramatically, as well as a pinch of Dendtritic salt. ROE is a dark green, syrupy looking ingredient and can be used at under half a percent (max) to your total. These days I like just adding vitamin e and dendritic salt. I am no longer really crazy about ROE.

I store my more precious essential oils in a wine cooler. This ensures a dark and cool place and stays at about 62 degrees F, about 62 celsius. Plus they can be on "display."