There are several ways unscrupulous manufacturers can cheat you out of getting your money's worth when it comes to essential oils. And even the most experienced aromatherapists can't detect some of them without a laboratory test. The four most common ways manufacturers modify essential oils are:
- Adulteration
- Dilution
- Degradation
- Rectification
Dilution is the process of "stretching" an oil by diluting it in some type of carrier. The United States has few laws specifically for essential oils and this allows manufacturers to sell diluted essential oils as "pure" or "natural". Usually dilution is done to save money and dilution of essential oils isn't necessarily a bad thing. If you're using essential oils mainly in the bath or for massage, you may not need botanically pure products--or the expense that accompanies them.
Degradation isn't so much an attempt to cheat you as it is an indication of the manufacturer's storage practices. Oxygen, heat and sunlight can all cause the essential oils to break down, chemically speaking, over time. Degredation mainly affects the scent of the oil but, in rare instances, can make the essential oil more toxic. Pine essential oil, for example, becomes a more likely dermal irritant when stored incorrectly.
Adulteration is similar to dilution in that an essential oil is "stretched" with another, cheaper oil but unlike dilution, adulteration is an outright attempt to defraud consumers. A perfect example involves Bourbon geranium, a highly sought-after and very expensive essential oil. To save money, manufacturers will sometimes "cut" the geranium with less desirable varieties from other countries or with essential oils from completely different species--without disclosing the adulteration on the label.
"Rectification" refers to the practice of re-distilling essential oils a second, third or fourth time. Sometimes rectification is done to remove undesirable constituents (eucalyptus is a good example of this) or to change the chemical components. (Ylang Ylang is often re-distilled multiple times and many aromatherapists consider the third or fourth distilling to produce the best-smelling oil.) Rectification isn't necessarily bad but it can significantly alter the scent.
To make sure that you're getting the best quality essential oils possible, buy only reputable brands from reputable retailers. Essential oils are expensive. You deserve to get your money's worth.
