Keep Essential Oils Refrigerated

Background Photo – © herbs-info.com

Did you know that if essential oils are stored at cooler temperatures, their shelf life increases? Essential oils are “happiest” at between 35 and 38ºC – approximately the temperature of a typical fridge – although note that the colder they get, the more viscous they become (less easy to pour – though warming them again will make them more liquid).

Being even colder i.e. in a freezer will not harm the oils but will not result in significantly increased shelf life – and of course the oil may well become so viscous that it will not pour or drip at all.

Note that if you are going to store your oils in the fridge that also contains food, don’t just leave them loose (in the manner of the photo) – but keep them in a tightly closed case or plastic container. This is because any oil that evaporates may cause food to pick up some of the scent of the oil, which would not be desirable.

Citrus oils are among the fastest to degrade and this is relevant to those using oils for aromatherapy as well as fragrance, because the amount of the active components in the oil diminishes over time. It’s not that the oil will “go off” so much as become less and less fresh and “less therapeutic” over time. In one scientific study, the monoterpene content of lemon oil decreased from 97.1% to 30.7% in 12 months. Limonene, the most abundant compound in lemon essential oil, was found by one test to have decreased remarkably from 68.5% to 20.1% over 12 months. ^[1]

One thing that is interesting to note is that there seems to be a correspondence between the volatility of the oil and the shelf life. Sandalwood, vetiver, patchouli are recorded as having a shelf life of 4-8 years. Anyone spot the connection between these three? They are all base notes in perfumery and their fragrance is longer lasting. It is even said by some that the quality of vetiver as a fragrance actually increases with age. Has anyone else experience of this?

Thanks to Robert Tisserand for bringing this to our attention. See Robert’s original article about keeping essential oils cold here.