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Integrity of Essential Oils

by Dr Akash Chopra and Julian Franklin(more info)

listed in aromatherapy, originally published in issue 55 - August 2000

One of the most frequently asked, and debated questions is: how do we know that the essential oil is 'pure'? . . . One would think it is a simple process to establish whether an essential oil has been tampered with during its journey from a farmer to manufacturer, and finally to the consumer.

One of the most frequently asked, and debated questions is: how do we know that the essential oil is 'pure'? The answers that are put forward vary, from looking at the GLC (gas liquid chromatography) trace, to a statement saying that our company has been buying oils in the market place for years from reputable traders and distributors. There seems to be very little thought, on the whole, to the integrity and provenance of the oil. One would think it is a simple process to establish whether an essential oil has been tampered with during its journey from a farmer to manufacturer, and finally to the consumer.

Rose Geranium plantation in the Vaalwater region of South Africa
Rose Geranium plantation in the Vaalwater region of South Africa

Protocols to Establish Purity

We would be wrong, simply because there are few accepted protocols or practices which have been put in place where the process can be readily audited. This is not to say that oils being produced at present are not what they are claimed to be, but rather we need to take the element of uncertainty out of the equation. The only real way that one can establish a criterion of purity is by putting in place traceable, verifiable protocols, which in turn lead to establishing integrity of the oils, or for that matter, any other botanical extract.

In order to indemnify those who are carrying out proper trade, we need to put in place the ability to go back to the source of production and monitor every step through to the eventual consumer, to ISO standards[1]. The point being made here is that, whilst the composition of the oil can vary, there is nothing to stop us establishing its absolute integrity; namely, has it come from a known growing platform to the end-user?

Our work in South Africa, India and United Kingdom for the last four years has been to address this uncertainty. We started in essence with a clean sheet of paper and looked at all stages of production, and started to implement methods which are documented in a form of GAP (good agricultural practices) and GMP (good manufacturing practices). This all leads to establishing traceability and hence by definition, establishes integrity of the oils.

Initially, we ignored the subjective comments regarding the products i.e. its top note is not right, or the chemical composition is not in line with those that have been accepted to be the norm for years. We were driven by exact science and processes, and not by rubbing the leaves, smelling, and making very subjective comments. We were acutely aware that the oils being produced may not be the 'right chemotype'; having an oil with a chemical composition which is normally attributed, with accepted variations, to that particular oil. This is where the system is open to abuse in the form of adulteration, simply because the oil can be made to conform by addition of calculated amounts of specific synthesized chemicals or blends of less expensive oils. This can make the whole process riddled with doubts as to the overall integrity of the product offered.

Adulteration of Oils

It is a worthwhile exercise to explore adulteration in detail, in particular as to why the market has a need for this, and how it may be possible to curtail this practice. It is a known fact that the volume of essential oils such as Rose, Lavender and Rose Geranium traded in the market is far in excess of the world-wide production of these oils. Adding synthetic chemical components, or in some cases low-value oils, makes up the volumes traded. The price that these essential oils fetch in the marketplace, makes it a worthwhile exercise to adulterators of these oils. It is ironic that some buyers purchase solely on the basis of aroma, and don't even examine the chemical and physical data, which may or may not be available in the first place. These data can be made available in the form of a material safety data sheet (MSDS) and a product specification sheet (Sheet One). These will incorporate ISO standards, produced by the International Standards Organisation based in Geneva, Switzerland, and supported by the BSI (British Standards Institution) in the UK, which will help to minimize adulteration as a first step.

The physical and chemical information provided, backed by documentary evidence at source, lends to traceability and a form of deterrent, if it is regularly audited and sampled. It is worthwhile pointing out that referring solely to the GLC (gas liquid chromatography) trace, which is upheld as a definite criterion for a pure oil, only reflects the relative portion of chemical components in a given oil. This can be manipulated by adulteration, and has been perfected by some producers and traders, as exemplified below in the case of Rose Otto and Lavender.

Adulteration of Rose Otto with Rose Geranium

Rose Otto costs £2500 per kilo[2]
Rose Geranium £190 per kilo[2]

(Table not shown here)

By means of mixing the natural oils, the resulting blend may well have a similar aroma; however the cost based on a 50:50 mix would be considerably lower. The GLC trace would be broadly in line with the norm, resulting in an acceptance in the market place in the absence of full data, and possible traceable audit. The above results can also be achieved by adding synthetic chemicals or a combination of both activities.

Similarly adulteration of Laveder oil with lavandin

Lavender costs around £70 per kilo
Lavandin costs around £35 per kilo

(Table not shown here)

Once again, it can be seen that mixing can make greater margins for traders and growers.

We have established that the price of oil obtained by the farmer from the supply chain is generally too low, which encourages adulteration at the primary production stage by the farmer. This has encouraged some suppliers to develop strategies whereby plant material, which will be processed for essential oils, are being transported many miles, even across continents. Adulteration at the production end of the chain usually will extend to processing plant material, which does not contain such high value components, or adding low value components, thus bulking out the oil. Such adulteration is usually easy to detect with a GLC trace.

Potential Remedies to Adulteration

We have overcome this failing in the system by selling from the farmers directly to the prime user of the oils and, hence, a 'fair' price. This price reflects not only a basic income, but allows for price fluctuations caused by supply variability, improvements to production infrastructure, and crop failures, and stabilizes socio-economic development in these predominately agricultural based areas of the world.

Further adulteration occurs during the supply chain. It is said that a supplier of essential oils is only as good as his supplier! At any stage in the supply chain, adulteration may occur when blending of essential oils or adding of specific low value chemicals can increase the value of an oil tenfold.

In conclusion, it is important to realize that the only effective way of establishing the integrity of an oil is to put in place batch numbering, along with traceable protocols, which can be audited periodically to ensure on-going safeguards. Further, it is important that the price of oils should reflect good financial returns to farmers who are able to meet market demands and, hence, eliminate the need to manipulate the products at source, or along its journey to the marketplace.


1. ISO (International Organisation for Standards) based at Bilbao, Spain for essential oils.
2. Prices listed in Phoenix Natural Products catalogue (September 1999).
3. BM Lawrence. Essential Oils, p63. Allured Publishing. 1992-1994.
4. Phoenix Natural Products analysis sheets for batch numbers 801315 and 833572.

Sheet One: Product Specification Sheet (Not shown here)


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About Dr Akash Chopra and Julian Franklin

Dr. Akash Chopra trained as an organic chemist at University of London. He formed a facilitation company, Biosys Ltd, based at Rothamsted Experimental station, Harpenden, UK, specializing in traceable essential oils and botanical extracts. He has spent some five years with his team understanding the growing, processing, and marketing of the extracts. This detailed understanding has led to major projects being facilitated with government funded institutes in South Africa and India. He is also involved in looking at new indigenous raw materials from India and South Africa, and at the same time addressing biodiversity issues. In some cases this has led to sustainable community-based projects ensuring that there are cross section benefits to the indigenous socio-eco system. Dr Chopra is in his early stages of involvement with Silsoe Research institute, Bedford UK, researching on aroma delivery systems along with work on novel ways of processing and managing alternative crops. He can be reached at Biosys Ltd, Rothamsted Experimental Station, Harpenden, Herts. UK AL5 2JQ. Mr Julian Franklin is head of Horticultural and Controlled Environment Services at Rothamsted Experimental station. He has worked with Biosys Ltd for the last 3 years developing strategies for growing essential oil crops in South Africa and the UK. He can be reached at IACR Rothamsted, Rothamsted Experimental Station, Harpenden, Herts. UK. AL5 2JQ.


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