Shelf life is a big topic in the aromatherapy world. Pretty much every aromatherapy and essential-oils blog, book, or commercial website discusses how crucial it is that the oils remain fresh—in other words, that they not come into contact with excessive light, heat, or oxygen (the latter process is called “oxidation”). Exposure to oxygen causes essential oils to “go funky” and lose their effectiveness. Citrus and conifer oils oxidize and age more quickly than other oils (they generally need to go after two years), while oils such as patchouli can last for decades(!) and even improve with age.
Here’s the challenge to essential oils’ freshness, in one word: headspace.
Sounds kind of psycho-spiritual and abstract, doesn’t it? As in, “I’m in a really great headspace right now.” But the term “headspace,” at least when it comes to storing essential oils (or any volatile substance, for that matter) simply refers to the empty space inside a container. The less of a substance is present relative to the size of a container, the more headspace is inside.
The problem with headspace: it’s full of oxygen. Even when an essential oil is bought fresh (from a dealer who rotates stock frequently and offers pure oils), and even when an oil is stored properly (in a dark bottle that’s tightly closed and under refrigeration) the oxygen within the container will degrade the essential oil’s scent and therapeutic value.
One solution to the problem is simply to buy your essential oils in smaller containers. At Tazeka Aromatherapy, we offer our 100% pure essential-oil blends in sample 2 ml and roller-ball 8 ml sizes (our diffuser blends come in 5 ml and 10 ml sizes), so you needn’t worry about nitrogen blanketing. Purchasing essential oils in larger quantities (15 ml and up) may offer a lower unit price—but if you aren’t going to use the contents before they go south, the economy is decidedly false. Remember, too, to store any oil you don’t use daily in the refrigerator, to prolong its life.
But another answer exists, too: nitrogen blanketing. Oxygen is lighter than nitrogen, so when nitrogen is put into a container, it will fall below the oxygen and “blanket,” or coat, the substance in the container—for our purposes, an essential oil. Unlike oxygen, nitrogen is “inert,” meaning that it won’t react with the oil the way that oxygen does. Nitrogen therefore protects essential oils from oxidization and prolongs their lifespan significantly.
Reputable manufacturers and distributors of essential oils blanket their oils with nitrogen and keep them under refrigeration in order to ensure that you, the consumer, receive a fresh and effective product. But is nitrogen blanketing solely for larger-scale distributors? Can we take advantage of nitrogen blanketing on a smaller scale, to protect our essential oils at home? Do we even need to?
Currently, not many nitrogen-blanketing products are on the market for smaller-scale aromatherapy practitioners. If you find that your essential oils are spoiling before you can use them completely and would like to use nitrogen blanketing at home to extend your oils’ lives, Nature’s Gift offers a product called Oxygen Barrier, a blend of nitrogen, carbon dioxide, and argon, to spray atop partially full bottles of essential oils.
Reputable distributors, refrigeration or cool storage, dark containers, and tight bottle seals—all are crucial to ensuring your essential oils’ effectiveness. When it comes to nitrogen blanketing, the choice is yours.