As the cool weather surrounds us, we seem to turn more towards using essential oils in our homes, and questions often arise as to how to store these precious (and often expensive) oils.
In order to maximize the life of your essential oils, they need to be stored much like wine; away from light and heat. When you buy essential oils they should be in dark glass bottles to protect their chemical constituents and we want to keep them in these bottles. Store your oils in a dark place, out of direct sunlight, and not in the bathroom where the heat of the shower could affect your oil's quality. A cupboard or a shelf in your bedroom closet is ideal.
Most essential oils that are stored properly can last a year or two, depending on how often they are opened and how much air is in the bottle. If you have a large but half-full bottle of essential oil, it would be wise to pour the oil into smaller bottles to minimize the air content in the bottle; less contact with air helps the oil to last longer.
Essential oils rich in monoterpenes, such as citrus and evergreen oils, can oxidize quickly and are best stored in the refrigerator to maximize their longevity. They should be used within a year, so it is best to buy these oils in small quantities. Interestingly, some of the heavier essential oils like patchouli and sandalwood actually improve with age!
You can tell that your essential oil is past its best if the colour or scent changes, or if the oil thickens. If you notice a change in your essential oil and think it had gone bad, it is still useful for cleaning purposes. For example, Pine and Lemon essential oils are not advised to be used on the skin once they have oxidized, but they still retain their germ-fighting properties and smell fresh enough to use for cleaning! (Remember that when cleaning you should always wear gloves, even if using natural products like essential oils.)
The best way to keep your essential oils fresh is to use them! Using your oils and keeping them stored appropriately will maximize both your investment, and your enjoyment!