Where can I find reliable information on essential oils?

September 11, 2009 11:47 PM

I need further information about essential oils, but I'm having difficulty cutting through the questionable information online.

Among my questions are:

1. Where can I find detailed information about extraction methods (books -- even expensive books -- are fine)?
2. What does "pure essential oil" really mean, and is that a legally-defined term in the U.S.? Can a "pure essential oil", for instance, contain solvents, waxes or resins from the botanical, other oils, etc?
3. Is there a way to tell through terminology whether benzyl benzoate is used (as it apparently sometimes is)? I'm allergic to that compound.
4. Where is the best place to find out any toxic effects of such oils used internally (I have The Commission E Monographs already)?
5. And, specifically, my google-foo is failing me: can anyone find for me pure violet flower essential oil, through any extraction method? I've seen this and this, both of which seem priced too low to be believable, and the latter link's owners confirmed that benzyl benzoate is present.

And yes, I've read Süskind ;-)

posted by quarantine to science & nature (13 comments total)

Some of this may be difficult to find out, as essential oils are used widely in perfumery, and perfumery is definitely one of those industries where secrets are guarded with jealous precision.

That being said, I find that most oil manufacturers are really nice, so if you do find a violet oil you want and you are unsure if benzyl benzoate is used, call or email them! If you tell them you're an interested customer with an allergy, they will probably be very willing to work with you. And I bet you're not the first to ask, either.

For violet oil, if you are looking for REALLY pure violet oil, you are probably looking for an absolute. It will be quite expensive, but you get what you pay for with essential oils. Absolutes are the oils of things that have very little oil overall (like roses, where it takes a truly ridiculous number of petals to create 1g oil). These absolutes, when you buy "rose" or "violet" essential oil, are usually diluted with other, cheaper oils that still blend with the overall smell of roses and violets, since otherwise the price would be pretty much beyond the reach of the ordinary public. Absolute of violet leaf is about $31/gram for instance. From what I understand, however, violet absolute is much rarer (although it may be cheaper now that liquid CO2 extraction is more widely used.)

Somewhere around there is a ridiculously awesome perfume industry website that shows you the molecular structure and gives a bunch of technical information, including (I believe) health warnings on essential oils. AHA! Here it is. It doesn't carry the health warnings but it does tell you the most common method of extraction for each oil, so it might still be helpful.

I am unsure about what the quality standards for an essential oil are, but I know that the purest you're likely to find will be "food grade." Unfortunately, the category of oils that get marked as food grade are very, very small, because many oils are dangerous to ingest, so that may not be the best way to judge.

Another good place to look for some answers might be the BPAL forums. You might need to register, but if you don't mind, search the forum with your terms and you should find some pretty extensive information-- I know there have been a lot of questions like this in the past. If not, ask! Sometimes the house perfumer, Beth, will even come into the forums and answer questions if no one else knows.

(And while you're there, have a look around-- they have some lovely violet perfumes...)
posted by WidgetAlley at 1:17 AM on September 12 [2 favorites]

I cannot answer your specific questions about essential oils, but, being highly allergic to benzyl compounds I understand the problem. The only place I've been able to be within 5 feet of a bottle of essential oil is in the shop run by the local (trained, certified) herbalist who told me that most of the stuff out there sold as pure essential oils is anything but.
posted by x46 at 1:23 AM on September 12

Are you familiar with the work of Tony Burfield? Click on "Essential Oils" for a brief discussion of extraction methods. For #2, he observes in the Aug 2007 newsletter , p. 23-24 that there really aren't any workable purity standards, anywhere, for e. o.'s used in aromatherapy (vs pharmaceutical, perfume or food sectors). He has an article on adulteration of e.o.'s here, which doesn't address your specific questions but you may find it interesting background reading.

My go-to person for essential oils says that vendors are allowed to call their oils "pure essential oil" even if the actual e.o. makes up only 10% of the stuff in the bottle, but I haven't got a cite for that assertion.

Burfield also has some discussion of oral toxicity. (Click "Magazine" in the left sidebar of his home page -- not Cropwatch -- then click "Safety" towards the top of the page, then "Safety Lecture: To Aromatherapy Organisations Council July 1999 London.")
posted by cybercoitus interruptus at 1:30 AM on September 12

Crap. Adulteration link is borked. Cropwatch home page, click "The Cropwatch Files" which brings you to a page of articles including the adulteration one.
posted by cybercoitus interruptus at 1:32 AM on September 12

I seem to recall there being a difference between "pure essential oil" and "natural essential oil". The first must indeed be pure, but the latter can be pretty much anything.
posted by Solomon at 1:42 AM on September 12

These absolutes, when you buy "rose" or "violet" essential oil, are usually diluted with other, cheaper oils that still blend with the overall smell of roses and violets, since otherwise the price would be pretty much beyond the reach of the ordinary public.

That's a very poorly structured sentence-- forgive me, I just woke up. :D What I meant to convey was more like: when you buy essential oil of rose or violet that doesn't say absolute on the bottle, it's the absolute diluted in complementary oils to make it more cost-effective.
posted by WidgetAlley at 2:26 AM on September 12

This discussion thread about violet essential oil might also be of use to you, although the consensus seems to be that no one makes one. My understanding is that violet notes in perfumery are entirely or almost entirely synthetic, due not only to cost of extracting the natural oil, but also to the fact that natural violet oil is so volatile that the scent degrades very quickly. If you do find a natural extract, it will be made from Parma violets (not the candy!), which might help narrow your search.
posted by timeo danaos at 5:09 AM on September 12

I used an earlier edition of this book when I taught a chemistry class to aromatherapy students many years ago. It has a great discussion of methods of extraction and lots of information about gas chromatography, which is the main method used to analyze EOs.

It's been a long time since I've thought about it but I think there are some EOs where benzyl benzoate (or very, very similar compounds) are naturally occurring. It may also be used as an adulterant and so there may be products where it's present in much higher concentrations than it occurs in unadulterated oils.
posted by Sublimity at 8:42 AM on September 12

In regard to toxicity, it is not widely known that many essential oils are extremely toxic to cats, even in small environmental exposures. Just want to toss that out there in case you have a cat, or in case another interested party reading this thread does.
posted by so_gracefully at 11:33 AM on September 12

You opened pandoras box. Violet leaf absolute is available widely. Violet FLOWER essential oil, absolute or concrete is not available to the public. Period. (High level trade only and it is never advertised online. Does not get sampled to industry outsiders). It is truly one of the rarest aromatics on earth. There are only several kilos produced per year and unless your uncle is a perfumer at Chanel you are unlikely to see it. Most EO's and aroma naturals are produced in tons, Here is a reputable source of commercial perfumery grade essential oils inlcuding violet LEAF absolute.

There is only one source of high quality EO's catering to the aromatherapy and amateur perfumery industry that does their own Gas Chromatography Mass Spectroscopic testing (very expensive) for authenticity, dilutants, contaminants and toxic solvents. GC-MS testing is the industry standard for sorting out what the hell is in EO's. Being natural and often gathered primitively their quality varies widely. This is why the industry has trended toward aroma chemicals (more easily standardized) to the detriment of the perfume industry. Add the temptation to alter for profit and the complete and utter lack of regulation worldwide and well, like I mentioned; pandoras box revisited. Kobashi routinely reject samples that have been contaminated from things as innocent as windborn contaminants from a neighbouring field into a so called organic field, etc.
posted by Muirwylde at 8:30 PM on September 12

Salvatore Bataglia's book is excellent. (One source for the book- the first one that pops up on Google) http://www.naturesgift.com/shop/?shop=1&itemid=330
Reputable suppliers will answer any questions you have and will also be able to supply you with a gcms report (gas chromatography-mass spectrometry (GC-MS) which will list all the components-should help with the benzyl benzoate issue.
It is important to look at the botanical name for whatever oil you are looking for (for example there are a variety of different botanicals of tea tree - meleleuca alternifolia, meleleuca quinquinerva etc. all with slightly different properties based on slightly different chemistry).
Quite often abosolutes are available as blends which makes them affordable and still very usable and effective. Rose absolute and jasmine absolute are two that I use which are blended in jojoba oil. You simple use 5 drops to equal one in your blend. I primarily use Eve Taylor essential oils which are very good quality. (She is a British aromatherapist and an absolute pistol of a lady. I have had the pleasure of meeting her).
Try directing any unanswered questions to the CFA (Canadian Federation of Aromatherapists http://www.cfacanada.com/).
I purchased some excellent reference materials from Danielle Sade, [e-mail], which included difficult to find information on the chemistry of EO's. I find it very useful.
Enfleurage in New York has violet leaf absolute. I have heard good things about this store.
I hope some of this is helpful.
posted by Wendy BD at 10:55 AM on September 13

What a fantastic response from knowledgeable people. AskMeFi consistently exceeds any hope of information quality.

Thank you Mirwylde for the recommendation of a firm that does mass spec testing for EOs. Very useful. Far more useful than the 99%+ of sites out there that tell me what magical spells or star signs the oils are most useful for.

FWIW, auroma.com claims they do mass spec testing on their oils, too, but I don't know if that's true, and I don't know what their standards are.

In Googling I found information that violet was one of the first oils synthesized, as the aroma is produced by exactly one compound. I lost the citation, but: can someone with better foo tell me the name of the chemical, and does anyone know of a reliable source for the synthetic? I absolutely don't mind lab-synthesized -- an organic molecule is an organic molecule, and we might as well not harvest a metric ton of violet petals for a kilo of oil -- but I would still be allergic to many of the adulterants of a synthetic oil.
posted by quarantine at 8:36 PM on September 14

OK, so, for posterity, it appears that alpha-ionone is the dominant chemical making up the violet aroma.

Accoring to this site,

The unique, fine, sweet fragrance of the violet flowers is dominated by ionones: alpha-ionone, beta-ionone and beta-dihydroionone.

The first two are available from PerfumersWorld.

Most sources contend that only the alpha is necessary to simulate the violet aroma.

Here is a data sheet for alpha-ionone (that site is fantastic, and among much other information, it is listed, undiluted, as a skin and eye irritant.)
posted by quarantine at 12:32 AM on October 1