How to store essential oils?
Essential oils should always be stored in amber (or other dark colored) glass
bottles away from direct sunlight and in cool to cold conditions. Some oils -
citrus and the precious, more expensive ones - are best kept in the fridge.
Preferably store bottles in airtight plastic containers so that aromas will not
affect food stuffs! The bathroom, where many keep their oils is not the ideal
place due to constant temperature changes and often hot, steamy conditions. But
that is really being perfectionist! We all have oils in our bathroom. However if
the bathroom has a window sill, do not leave them there. A very small minority
of oils solidify in the cold weather, some are semi-solid all year round.
Absolutes may solidify in cold weather due to their high proportion of natural
Essential Oils (for example Cedarwood ) may solidify owing to the high level of sesqui-terpenes (cedrol). Fennel solidifies due to the high level of transanethole. Rose Otto semicrystallises due to the presence of natural waxes (steropenes). To rectify this, simply warm oils in a bowl of hot water for a short time before use. Most essential oils have a shelf life of at least two years. The exception is the citrus and pine oils which pass their prime after 6-9 months. Some oils such as frankincense, patchouli and sandalwood can improve with age. To keep oils in optimum conditions decant when bottle is less than half full - only necessary on sizes over 10ml and if oil is not quickly used. Do not be alarmed if the aroma and colour of certain essential oils change. The many natural chemical components in essential oils are extremely complex and natural changes occur. For example, chamomile german when very young is a dark greeney/blue colour but will change to a midnight blue in time. Freshly distilled lavender will have a very herbaceous aroma - not pleasant - but will change over time. A useful tip to quicken the process of improving the aroma is to take off the lid and leave oil exposed to air for a week or two. These processes occur when you buy truly pure, natural and unadulterated oils. They do not con-form, but evolve in a natural way.
As with essential oils, carrier oils should be stored in a cool, dark place away from direct sunlight. No need to store carrier oils in amber bottles. Certain oils are best stored in the fridge because of their high content of gamma linolenic acid (fatty acids). These include borage, carrot and evening primrose. Oils such as avocado, jojoba and macadamia may solidify in the cold weather due to their high content of natural waxes. To rectify this, simply warm oil before use. Cold Pressed Carrier Oils - except for grapeseed where this process is not possible - and are as natural as possible. Some such as calendula and macadamia have natural vitamin E added to help prolong shelf life. Avocado, coconut, grapeseed and jojoba have been refined as they would be unpleasant to use otherwise. Carrot oil is produced by maceration. Use this oil sparingly or blend with other carrier oils as due to its strong color it can stain both skin and cloth.
Our wheat germ oil is unrefined so as to retain maximum natural vitamin E. Calendula oil is an infusion of calendula flowers in sunflower oil and St. Johns Wort is the herb, hypericum, infused in virgin olive oil. If oils are stored according to the above recommendations they should keep and perform well. Always decant oil into a smaller container when there is more air than oil in the bottle as it is this that can cause rancidity.