Tuesday, December 2, 2008

Myth Debunking 1: What Are Aldehydes, How do Aldehydes Smell and Chanel No.5

Ask any aspiring perfumista about aldehydes and you will hear that they are synthetic materials first used in Chanel No.5, that thanks to them this is the first and the prototype of synthetic fragrances and that aldehydes themselves have a champagne-like, sparkly, fizzy odor that makes the fragrance fly off the skin. This is what they have been told time and again. Ask any seasoned perfumephile and you will hear that aldehydes have a waxy, citrusy or rosy aroma, like snuffed-out candles (Luca Turin was instrumental to that with his references appearing in “Emperor of Scent”). The truth? It’s a little more complicated than either!

It’s a fact that aldehydes became famous through their introduction in copious amounts into the formula of Chanel No.5 in 1921. However No.5 is definitely NOT the first fragrance to feature synthetic aldehydes :
~"Though Chanel No. 5 is recognized as the first Aldehydic fragrance, created in the mid-twenties, the truth is that the first Aldehydic fragrance was Rêve D'Or(Golden Dream), [1]created in 1905 by Armingeat." (sic[2]).
Nor is No.5 the first modern perfume to feature synthetic components (that honor belongs to Fougère Royale -Royal Fern- by Paul Parquet for Houbigant in 1882). Aldehydes themselves are organic compounds present in various natural materials (for instance natural citrus essences such as the one from orange rind, rose oil, pine essence, citronella and cinnamon bark ~they even appear in bovine heart muscle!). Several essence reconstitutions by chemists involved using aldehydes as various types can also be synthesized in the laboratory.

Aldehydes (same as ketones) are organic compounds which incorporate a carbonyl functional group (that's C=O). The carbon atom of this group has two remaining bonds that may be occupied by hydrogen or alkyl or aryl substituents. If at least one of these substituents is hydrogen, the compound is an aldehyde. If neither is hydrogen, the compound is a ketone. The majority of aldehydes and ketones have strong odors. Ketones generally have a pleasant smell and they are frequently found in perfumes (e.g. muscone in musk-smelling colognes). They are also used in food flavorings. Aldehydes vary in smell with most of the lower molecular weight smelling bad (rotten fruits), yet some of the higher molecular weight aldehydes and aromatic aldehydes smell quite pleasant and are thus used in perfumery. Formaldehyde is the simplest aldehyde with a central carbon atom bound to two hydrogen atoms (H2C=O). Discovered in Russia by A. M. Butlerov in 1859 it is very reactive, used in dyes, medical drugs, insecticides and famously as a preservative and embalming fluid.
Aliphatic aldehydes possess intriguing smells outside the realm of simplistically nice: butyraldehyde for example smells of rancid butter (from βούτυρο/butyro which means "butter" in Greek)! Acetaldehyde is the name of the shortest carbon chain aldehyde and is one of the oldest known aldehydes (first made in 1774 by Carl Wilhelm Scheele). Its structure however was not completely understood until Justus von Liebig determined the constitution of acetaldehyde 60 years later, described its preparation from ethanol, and baptised this chemical group “aldehydes”.

Hardly a fragrance exists without some kind of aldehyde in it, which incidentally makes insisting the greatness of No.5 is due to its synthetic materials comparable to saying that the Pyramids are monumental because of their shape alone. It is the cleverness of marketing and the propagation of a myth that No.5 was meant to evoke an unnatural smell (because supposedly Coco Chanel insisted that she wanted a perfume smelling of a woman and not of flowers ~"women do not want to smell of a bed of roses") which gave rise to this confusion. Chanel No.5 and No.22 later owe their vivid sprakle to a specific subgroup of aldehydes which are called “fatty”: strings of carbon atoms (between 8 and 13) coded in accordance to that number of atoms (ie.C8) with nomenclature deriving from Greek numerics, such as octanal from οκτώ/octo (=eight), in which each of the 8 carbon atoms is connected to two hydrogen atoms. The “bouquet” of aldehydes C10, C11, and C12 in Chanel No.5 became so popular that all consequent “aldehydic fragrances” used that sequence of aldehydes, giving a fizzy perfume-y scent that is quite characteristic with the direct result of having the perfume lover confused as to how aldehydes themselves smell. Fatty aldehydes have a citrusy or floral note, and a pronounced fatty/waxy/soapy tone which is very apparent if you consider a modern fragrance that uses them in high ratio: Sicily by Dolce & Gabbana. The soapy feel is unmistakeable! As an exercise compare that smell with your Chanel No.5: you will pick up the soapy facets in that one as well. Another reason that they read as “soap” is exactly because they have been used in the production of soap for years to give that fresh lemony feel.

Most widely used aldehydes in perfumery are C7 (heptanal, naturally occuring in clary sage and possessing a herbal green odour), C8 (octanal, orange-like), C9 (nonanal, smelling of roses), C10 (decanal, powerfully evocative of orange rind; Citral, a more complicated 10-carbon aldehyde, has the odor of lemons), C11 (undecanal , “clean” aldehydic, naturally present in coriander leaf oil~also used is unsaturated C11 undecen-1-al), C12 (Lauryl aldehyde evocative of lilacs or violets), C13 (waxy, with grapefruit tone)and the infamous C14 peach-skin note of Mitsouko: technically not an aldehyde, but a lactone ~gamma undecalactone.

Often the compounds are patented under commercial names; therefore their true nature remains arcane even to perfume lovers who might have seen them mentioned. For instance Triplal, a patented molecule by IFF: its chemical name is 2,4-dimethyl-3-cyclohexene-1-carboxaldehyde. Its smell? Powerfully green and herbal, like crushing ligustra leaves between fingers. None of the characteristic aldehydes of Chanel No.5!
One interesting ingredient is phenylacetaldehyde which has a pronounced green note (top in natural narcissus and thus used to recreate a narcissus note in perfumery). The hydrocinnamic aldehydes are another family of materials from the manipulation of benzene and their odor profile resembles lily of the valley (muguet) and cyclamen. One of them is the famous Lilial (patented name for lily aldehyde; also known as Lilistralis), widely used in the replication of that elusive natural essence, lily of the valley. Another is Cyclamen aldehyde (usually produced with cumene as a starting material).
Aromatic aldehydes have very complex chemical structures but are the easiest to identify by smell. Anisaldehyde smells like licorice. Benzaldehyde on the other hand, has an odour profile of almonds and has several chemical constituents: cinnamaldehyde, amylcinnamic aldehyde, hexylcinnamic aldehyde. Condensation of benzaldehyde with other aldehydes gives a series of α-substituted cinnamlaldehydes, the lowest member of which is used in the production of cinnamyl alcohol, very important in the production of spicy perfumes (cinnamon note). Higher members, on the other hand, such as amylcinnamic aldehydes (ACA) and hexylcinnamic aldehyde (HCA) project a fatty jasmine impression despite their abscence from natural jasmine oils! Most synthetic jasmine perfumes today use one or both because they are inexpensive (Their fibre-substantive qualities also make them perfect candidates for laundry detergents and fabric conditionners). The hawthorn or aubépine note, rendered synthetically in perfumes for several decades, is produced via anisic aldehyde (p-methoxy benzaldehyde) and it has been sublimely woven into the gauzy cloth of Après L’Ondée by Guerlain (where it sings along with heliotropin). Additionally, the aldehyde vanillin is a constituent in many vanilla-scented perfumes. So nothing is as simplistic as one might assume!

Aldehydic fragrances include (click links to read corresponding articles/reviews): Chanel No.5 and No.22, Lanvin Arpège, Guerlain Liu and Véga, Worth Je Reviens, Millot Crèpe de Chine , Balecianga Le Dix, Revillon Detchema, Caron Fleurs de Rocaille (not Fleur, singular), Infini and Nocturnes, Myrurgia Joya, Jean-Charles Brosseau Ombre Rose , Molyneux Vivre, Lancome Climat, Givenchy L’Interdit, Piguet Baghari, Madame Rochas and Mystère by Rochas, Rive Gauche by Yves Saint Laurent , Paco Rabanne Calandre, Estée Lauder Estée, White Linen, Pure White Linen, Van Cleef & Arpels First, Nina by Nina Ricci (the old formula in the ribbed bottle), E.Coudray Musc et Freesia, Bill Blass Nude and Amazing, Hermès Amazone, D& Sicily, Divine L’Ame Soeur, Serge Lutens La Myrrhe, Frederic Malle Iris Poudre, Ferré by Ferré, Agent Provocateur Maitresse, Annick Goutal Folavril, Le Labo Aldehyde 44.
Hermès Calèche is poised between floral aldehydic and floral chypre in some taxonomies.

[1]Bernand Chant, British Society of Perfumers 1982
[2]Armigeat is perfumer Pierre Armigeant (1874-1955) who composed Floramye and Azurea for L.T.Piver

Painting Gueridon 1913 by Georges Braques, courtesy of allposters.com. Chanel makeup ad via Bellasugar.


  1. Anonymous14:00

    Thanks E for such an informative yet by no means dry discussion of these fascinating materials. I recognise myself maybe three years ago in the sparkling descriptor and now know more. Plus I love the idea of twisting that saying about somebody's sh*t smelling of roses - and instead saying it smells of C9! donanicola

    1. Anonymous04:02

      Elena, you've opened my eyes on modern perfumes! It's a world of deception! And I absolutely hate being manipulated. Thanks!

  2. All say it again: Helg when are you going to get published!? Great article and a wonderful look at aldehydes.

  3. So glad to see this., I had been meaning to write about aldehydes for a long time,, and can now send folks over here to read this.
    I have seen so much mis information on blogs. You would think that aldehydes came from outer space.
    Good Job!
    Liz Zorn

  4. What a delightfully informative article to read. Thank you.

  5. Now I am a bit lazy to Google this, but is C16 also an aldehyde?

    I was testing Cologne du 68 the other day, there was some Chanel-aldehyde-feeling over it, am I only imagining this?

  6. Hi, E -- thanks for that very informative look at aldehydes, which should be required reading for every perfumista/o.

    It is useful to know that when the word "aldehydic" is used, it tends to refer to that specific "bouquet" of aldehydes C10, C11, and C12 as popularized in Chanel No. 5, even if the aldehyde family itself is much more diverse that just that.

  7. You have a talent for picking just the thing I've been wondering about! No. 5 always smelled waxy/ soapy to me, never knew why!

  8. N,

    thank you for your most kind words.
    What a witty comment that would be, huh? I can see you saying it with a straight face producing surprised looks ;-)

  9. J,

    awww...thanks so much for all your support sweetie. Well, I am published, don't you know! (I guess nobody reads my profile)
    Of course it would be best for me to really get my bum down and write a history book about frags.

  10. Liz,

    you honor me so much saying so, I appreciate it, especially coming from a perfumer like yourself.
    Thanks for directing people to my venue ~and btw, I have come across some samples of yours which a friend sent me in a swap: interesting things!:)

  11. D,

    you're very welcome and thanks so much for your compliment (I know you have high standards!)

  12. L,

    it's strawberry glycidate, which is used in flavoring (and in scenting one assumes).
    I am keeping you in a little suspense on Cologne du 68 as it will be reviewed here soon.

  13. Thank you J :-)

    Yes, I think it cuts lots of the confusion and misunderstanding if one realises that "aldehydes" and "aldehydic fragrance" are not interchangeable definitions.

  14. LLM,

    in that case I am very happy that my devination powers have matched your good nose!

  15. Great info about aldehydes...appropriately, I am wearing Liu today, my "No. 5 alternative". I have always gotten an "off" smell from No. 5, a strong whiff of insecticide. Could it be a proprietary molecule that Chanel uses? I do not have this problem with other aldehydic fragrances. Did I just decide to hate No. 5 at some point and convince myself that it smells awful? It's all very curious.

  16. Anonymous22:40

    Very impressive and informative! I agree with Jenavira - I'd love a perfume book of yours.


  17. Ah, the kind of article I'll read a few times, more and more carefully each pass...science being one of those things I might have been interested in had I not had such miserable teachers along the way. (So, right now, my strongest association is ketones & pregnancy, because I do believe I recall regular testing to make sure I was NOT producing those...taking me to an alternate realm of Donanicola's observation.)

    I especially appreciate the handy list of aldehydics, and the suggestions for comparison. I enjoy these mini-experiments...

  18. Anonymous05:34

    Dear Helg,

    Thank goodness you spoke the whole truth about aldehydes. As you know I don't believe aldehydes are the powdery ingredients people reject these days (I think it's the underlying ideas people reject due to the evolution of lifestyles). Nor do I believe the classic cocktail was first used in Chanel No. 5: of course Beaux was fascinated by the structure of Quelques fleurs by Houbigant before he composed his Chanel compositions.

    Just one more detail: I believe anisic aldehydes are the necessary components when composing a hawthorne accord? Just a minor detail but I remember it being stressed when I was reading old perfumery texts years ago.



  19. Anonymous09:02

    Historical perfume book: Yes, write!! :) (but I know so very well the problems connected with finding "free" time to concentrate on large projects..)

    I really enjoyed reading this very informative piece on aldehydes and/in perfumery (and got olfactory memories from my "pre-history" and the organic chemistry lab)

  20. I'm going to echo everyone and say this is really useful- and that I wish I had a more scientific brain, or more interest in making my brain work that way...

    Yes perfume history book please!

    By the way I was reading some of your older posts and found the poem The God Forsakes Anthony- I was blown away, it's absolutely beautiful isn't it. So thanks for leading me to it.

  21. Charlotte Vale with the very cinematic name,

    thanks for your most kind compliment and your very interesting comment! How lovely that you're wearing Liu! (isn't it beautiful)

    I think that it all depends on which version of Chanel No.5 you're smelling: edt/edp/edc/parfum? current juice/less recent/vintage/paleolithic? It varies greatly I have come to witness by personal experience, although we've been assured that the standards are maintained.
    I am not aware of any specific ingredient that only No.5 uses and no other brands have access to. I do believe however that No.5 is more musky than most (at least it used to be) and that usually produces interesting results. Insectide (=bug spray) is usually the feel that many people get exactly because very popular fragrances have had their formulae simplified for use in the functional products industry (ie.bug sprays, in this case)> I have this similar case with Poison and a coach-roach killer by Bayer. Don't know if this helps overcoming the aversion though...However the recent more modern versions, like Elixir and Eau Premiere are more sympathetic to many people who didn't like No.5 before, so maybe try those?

  22. Donna,

    thank you! You know, I should probably give this some thought ;-)

  23. S,

    ain't that the truth about teachers! They have such a crucial mission and they often are not suited to the job to the detriment of both themselves and their poor students...
    Ketones are produced when the body is processing too much protein from what I recall(ketoacidosis I recall is what happens when the body is going into an extreme mode of burning itself up for fuel when there is no glycogen present ~diabetics are also adviced to watch for ketones and pregant women too to watch for both glycogen and ketones for various reasons of possible toxicity to the fetus, right?)

    Good luck with the experiment! Can't wait to hear your impressions :-)

  24. Thanks A for chimming in! (just the kind of post that needs your comments)
    I agree that there is a certain feel that people reject and not powderiness (btw, I don't find No.5 that powedery), especially if we consider that several modern bestsellers are VERY powdery: Cashmere Mist, Kenzo Flower, Loukhoum by Keiko Mecheri and so on...
    I had referenced anisaldehyde for hawthorn in my review of Beige by Chanel. Perhaps I should add this here too!

  25. S,

    you're very welcome and thanks for saying so. I believe every field has its own charm and chemistry as well :-)

  26. K,

    oh, honey, but it's not a prerequisite; anyone can enjoy fragrance whether or not they analyze it in a nerdy manner like I do.
    On the other score, will try to reply to popular demand then :-)

    And this is my favourite poem of them all (so happy you found it and liked it!): I find Cavafy's poetry full of meaning and of grandeur in the little and bigger defeats of life...*sigh*

  27. E, I can see why it's your favourite, it's wonderful... also sighs. I am going to have to look for more of his work.

  28. Yeah...and it marked a very poignant point in my life too....

    Look here:
    C.P.Cavafy Poems
    (I ADORE The Satrapy, Body remember, Of Coloured Glass, In the year 200BC, Poseidonians, He asked about the Quality...so many, really)

  29. And of course The City......
    (english translation under "more info" on the right)

  30. Thank you so much for this and the recommendations. The City, Body Remember and He asked about the quality particularly resonated with me right now but I will definitely read more and again. I think I might need to get me a book of his work.

    The poems translate so well, or has been translated very well.

  31. Anonymous16:19

    E, thank you so much for this article. When I was a total beginner in the world of scents, I was told to go and try Estee Lauder's White Linen as a good example of aldehydes. I don't think that I can wear White Linen, but other aldehydes from your list are simply great.

  32. Thanks for responding to my post about No. 5!

    I doubt I've tried anything manufactured before the 1980's. Have done the edt, edp and recently pure parfum...bug spray all the way. Next time I'm at the mall, I'll try the Eau Premiere. Who knows, maybe it will actually smell like perfume!

    Interesting point about the musk. As far as I know, musk smells like musk to me, however, I don't like it all that much. I tend to steer clear of perfumes described as "musky" and look for things with woody and/or mossy bases instead. Maybe there are other musky fragrances that would come across as bug spray that I simply haven't tried because I'm a bit of an animalic-phobe.

  33. Helg,

    Your article on aldehydes is excellent. I'm going to suggest that readers (beginning and amateur perfumers) at Yahoo group Perfume Making, read all of your writings. I'm impressed that you even mentioned that C-14 "aldehyde" is not actually an aldehyde. The same is true of C-16 (strawberry), which you probably know.. but someone asked.

    Michael Storer

  34. Hi Michael and thank you for your wonderful compliment and your very flattering suggestion.
    Indeed the confusion about aldehydes needed a little sorting out, which this humble project tried to accomplish in some small degree: And then again we have C18/gamma nonalactone! ;-)

    I welcome your comments any time.

  35. Anonymous16:12

    Thank you, Helg, for publishing this extract from Chandler Burr's book. I have a new respect for him, being a perfumer myself, in that he extolls the virtues of synthetics and the profound limitations we'd have without them. In my opinion, too, I find many "naturalists" tantamount to religious fundamentalist in that they are simply incapable of hearing any other viewpoint. So many of the wonderful aromas we've had or well over 100 years come from ingredients discovered in laboratories. The world of fragrance would indeed be sad without them.

    I struggle everyday with trying to write profiles of my perfumes without using, for example, the word aldehydic. But in reality, it can't be done. This would be a world without Chanel No. 5 and many others if it weren't for perfumer's *complete* palate of notes. Still, I ask myself how to describe these additions to a public that seems to want to deny that they even exist, even though there is ample romance in their discovery alone... Thank you, and keep up the good work...

    Michael Storer, perfumer

    1. Anonymous22:55

      Hi Michael, came across this fascinating stream whilst trying to find out what HO11 means on the base of a bottle of rive gauche that is described as vintage. I had wondered if it would lead me to a pre 2003 date or if it was an aldehyde, but can’t see any HP prefixes. Would you have such information? I’d be so grateful to be able to be able to know the source/date/detail. Sheena 🌸

  36. Xavier Aware03:57

    In the interest of open information what this article does not explain is that aldehydes in their natural organic form are, as in citrus rind and citronella, natural mildicides and insecticides. That is why they are used in concentrated forms as insecticides.

    The Cancer Prevention Coalition www.preventcancer.com has a whole article on their dangers to the body.

  37. Michael,

    thank you!

    Chandler should be credited with opening up the dialogue and that's priceless. He paved the way for openness which is something not even LT did.

    I would propose the term "inedible" but that might not seem so attractive to customers. But several gorgeous "notes" do seem like the opposite of "edible" don't they? Soap, powder, earth, that piercing sharpness of some aldehydes...several.

    Thanks for your support on the work done! Much appreciated. :-)

  38. Xavier,

    I realise that there might be dangers, but IMHO it's beyond the scope of this particular article which was more of an educational resource from the point of view of perfume lover. At least aldehydes in perfumery are used in relatively small amounts and are not ingested. Same with coumarin and fyrocoumarins etc.
    There are many articles (here and elsewhere) which focus on the claims/testimonies of dangers for particular ingredients and are easily Googlable. Thanks for providing the link to the Cancer Prevention Coalition, will give it a lookg.

  39. Anonymous18:13

    Also Cabochard by Gres


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