Shelf Life and Storage of Essential Oils

Hello friends,

I recently took a class from the TisserandInstitute.com with Robert Tisserand as the instructor. Some of you might recognize his name as he is a leading expert in the field of Aromatherapy. He taught that the shelf life of Essential Oils is basically determined by two things, oxidation and storage. Rather than write a lengthy email about what I learned, I decided to give you my “cliff notes” in outline form because I found it easier to remember what Robert discussed.

1. Oxidation, which never stops, is the chemical substance changing because of the addition of oxygen. The downside of oxidation is change in color, loss of potency, and the oils may become more hazardous (Essential Oils are considered hazardous waste).

Following are points of oxidation:

A. Oxygen

     i. oxidation is a slow process but the more air in the bottle increases speed of oxidation so don’t shake bottles

     ii. decant(or pour) to smaller bottle as oil is used

     iii. only spray 30 ml or larger bottles

B. Light and storage     

     i. amber glass screens out about 90% of light

     ii. blue glass screens out about 70% of light

     iii. clear glass screens out about 10% of light

     iv. if oils are kept in a dark place then glass color is not as important

     v. ultra violet radiation does cause oxidation

C. Temperature

     i. from Svante Arrherius, Swedish scientist and 1903 Nobel Prize winner in      Chemistry: “A temperature rise of 10 degrees Centigrade (18 degrees Fahrenheit) doubles chemical reaction rates”

     ii. reducing storage temperatures can increase life span

     iii. keep in refrigerator as Essential Oils like cold, not warm temperatures

     iv. some oils will solidify in cold but will liquify after warming

     v. citrus oils like to be in the freezer

     vi. Essential Oil smell will/can be absorbed by other foods so store in closed containers

     vii. the colder the oils are kept, the longer it takes them to oxidize, hence the longer they remain viable

     viii. when making products from Essential Oils, store those ingredients in the refrigerator

D. Constant change

     i. change in smell is usually not a good thing: one exception is Patchouli as smell does improve with age

     ii. migration = some oils slowly migrate into & through bottle cap

     iii. oils can leach through certain plastics, hence the emphasis on glass storage, suitable plastics are HDPE or PET, leaching may not happen with diluted oils

E. Addressing oxidation

     i. an oil is oxidized when oil changes color

     ii. oil becomes more viscous (sticky, thick and hard to pour)

     iii. citrus oils may become cloudy (often a sign of water being present)

2. Ideal storage conditions

    a. Buy only what can be used in a reasonable time (not a long-term storage item)

     b. Store in cooler temperatures

     c. Store in glass containers with correct glass color

     d. Limit air space in bottle

     e. Always replace cap after using oil

     f. If protected from oxidation, oil will keep at least 12 months and perhaps up to two years or longer (depends on the oil)

     g. If kept in refrigerator and used within 12 months, don’t need to worry about oxidation

3. What I learned

     a. Disposing of oxidized oils

         i. shouldn’t diffuse

         ii. probably shouldn’t use for cleaning products as vapors shouldn’t be inhaled

         iii. can use for insect control, i.e. cutting off any ant trails

         iv. follow hazardous waste disposal guidelines in your area

     b. Shelf-life guidelines vary depending on opinions and source

     c. Can’t know how old oil is when you buy it, so start counting when the bottle is opened

Educating myself about Essential Oils is an ongoing process where I’m finding that I don’t know as much about Essential Oils as I thought. This class has taught me that I need to rethink my storage and usage of them as the value of having viable Essential Oils as part of my health arsenal is too great and too expensive to not take proper care of them.

I’m finding Joy in this journey of discovery and learning.

Until later,

Roxanne