What is the Shelf Life of My Aromatherapy Blend? This is a popular question we get from students and customers. They want to know, “how long will my blend last, shelf life wise?” What they are really asking, is how long will my blend work with the potency it has when you first make it? Well, that is not a cookie cutter answer with just one set amount of time. There are several factors that come into play to determine how long it will hold its potency and have its scent last, without starting to smell funny.
Aromatherapy Blend Potency Factors
Specific essential oils have a certain shelf life. Citrus oils do not last as long as floral, spices and camphoraceous scents. And essential oils that comes from woods and resins, have a longer shelf life than both citrus, florals, camphoraceous and spices.
In aromatherapy, you have top, middle and base notes. This tells you how potent something is, how long it will last, and can guide you on how many drops to add to a formula. The molecular weight (light to heavy) tells you how volatile an oil can be. High volatility means it gives an immediate effect, doesn’t linger, and doesn’t last long, smell-wise and in shelf life. For example, frankincense comes from resin, and is considered a base note. This tells you that it is more stable in its scent quality, will last a long time (over two years as long as it is not adulterated, or exposed to heat and air) and can overpower a blend if you use too much.
- Top Notes include Citrus oils. These do not last a long time (6-9 months) before the scent starts to “turn” or smell different. The potency of its therapeutic properties also starts to decrease after 9 months-ish. High volatile oils tend to be citrus oils with chemical constituents such as limonene and pinene.
- Middle Notes include essential oils that come from the leaves, herbs, flowers, berries, grass, roots and spices. These are stronger (scent wise & in molecular weight) than citrus scents. Thus, will last longer, up to 2 years in scent power and potency. When you add a middle note to a citrus note, it will extend the shelf life of that blend by a few months. Hence, citrus only blends have a shorter shelf life than blends that contain citrus and middle notes such as florals and spices. Chemical constituents giving with a stronger molecular weight are chamazulene and caryophyllene.
- Base Notes are hearty, strong and deep scents that come from some woods and resins. These have a lengthy shelf life, thus when you combine with top and/or middle notes, it will extend the shelf life by several months, or a year.
Other factors that can affect scent quality and potency are:
- Heat exposure such as high temperatures. Do not keep your aromatherapy blends in high heats such as a parked car in the middle of the summer months.
- Frequent or long durations of the essential oil being exposed to air (leaving the cap off for a while after use) can increase its oxidation rate, meaning it increases the rancidity rate.
- Light exposure such as direct sunlight and fluorescent lights. Direct sunlight can heat the blend up too much, causing the scent quality to break down. The EMF’s from artificial lighting can deteriorate the energetic vibration as well as scent quality and potency.
- Negative energy exposure. Like people, the essential oil’s vibration frequency is sensitive to negative thoughts, words, feelings and environment. This is one reason I recommend you grounding yourself and leaving “baggage” at the door before you start blending with your oils.
- Frequent change in temperature. Some aromatherapists store their essential oils in the fridge. This can preserve its quality and extend shelf life. However, there are a few caveats with that. Essential oils, like people, do not like to go in and out of hot and cold temperatures repeatedly. For example, if you are blending 10 different products and several call for lavender essential oil. You don’t want to use in one blend, then put back in the fridge, and 5 minutes later take it out again, and so forth. You can store in the fridge until you need it. Then take it out, use if for however many blends you need to make. Then you can return it to the fridge. I have found storing your oils in a cool, dark cabinet or closet has been suffice when it comes to optimal shelf life of essential oils and carrier oils.
- With certain carrier oils like coconut oil, if you store in the fridge, it will solidify. When you remove and store in room temperature, it will liquify. The oil has a strong composition so in that case, it does not interfere with the therapeutic potencies.
How long does a room spray or diffused scent last in the air?
It depends on the square footage of the room and if it’s an open or closed in area. Ventilation plays a role as well. If you have competing scents, such as a chemical-based cleaning product or food cooking in the kitchen, this can overpower the aromatherapy scent, making it not last long at all. On average, if there is satisfactory ventilation, open area of 400-600 SF, it can linger in the air anywhere from 15 minutes to 2 hours. If you do al all citrus blend, it will not linger very long. If you add in Middle and/or Base Notes, that will extend the scent duration.
There is something called Olfactory Adaptation. This is when you have been around a scent for a certain period of time, then you can’t smell it anymore. Your olfactory nerves have “adapted” or filled up with that scent, so you can no longer detect its odor. If you were to walk outside of the room, and re-enter, you would smell it again because it “cleansed your nose”. Someone with damaged olfaction such as anosmia (no sense of smell), may have a harder time smelling a scent, and the duration may be lighter, or shortened.
How quickly do the essential oils lose their therapeutic quality when diffused?
Well, the short (and obvious) answer is once the oils are burned off and water dissipates. Anytime essential oils are exposed to heat, it starts to deteriorate and break down the scent molecules. Therefore, this will start decreasing therapeutic value. If you use an ultrasonic or nebulizing diffuser, this uses a vibration to emit the scent molecules, thus reducing the rate of deterioration. A necklace diffuser is a great option, because the scent doesn’t get “burned”. However there may be increased olfactory adaptation since it is so close to your nose, with direct and constant inhalation therapy.
If I combine essential oils in a carrier oil or lotion base, how long will it last?
When you combine essential oils in with herbal, botanical and liquid material, you have to take into account the shelf life and quality of those ingredients. To determine overall shelf life, you can average out the shelf span for each ingredient. Of course, the sum of all of the parts create a synergy and can either increase the shelf life or decrease it. For example, if you add in fresh plant material (fresh rosemary infused olive olive), this will decrease the shelf. However, if you use a rosemary tincture or extract, it can enhance it, as it possesses preservative properties. Shea butter or beeswax would have a shelf life similar to Middle Notes. Liquids such as liquid plant enzymes, hydrosols and distilled water would also be in the Middle Note shelf life range.
Of course the goal of any aromatherapy blend is to use it, right? You should make enough to use it up within 3 months, just as you would any personal care product. It works when you use it, not when you store it in a drawer. With that said, I usually plan on 6-9 months of a shelf-life before potency and therapy will start to lessen. Other determining factors to consider for a product shelf life are:
- Quality of the essential oils and ingredients you are using – the better, more organic the quality, the shorter the shelf life as there are no preservatives or synthetics to decompose
- Exposure to heat and sunlight can decrease shelf-life and increase rancidity
- Ingredient integrated together such as all citrus oils or citrus plus flower oils plus a longer shelf life carrier oil such as castor oil. If a blend has some Base Notes in it, it will lengthen the shelf-life. Certain carrier oils are heartier and thicker than other oils, indicating it can have a longer shelf life. Review the carrier section of the course, or in the JennScents Holistic Aromatherapy Comprehensive Guide, page 171.
Make sure when you are “aromatherapy-ing” you follow the proper safety guidelines. This can play a huge role in overall therapeutic value of the aromatherapy experience.
Disclaimers: Information provided is for educational purposes only and is not intended to treat, diagnose, cure or prescribe. It is recommended that if serious health issues exist, you consult a licensed medical provider. JennScents does not assume liability or responsibility for the use and/or misuse of this information.
References: This blog contains excerpts from JennScents Aromaversity Certification Courses and the JennScents Holistic Aromatherapy Comprehensive Guide.
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