Perfume Vocabulary & Fragrance Notes : Indole, Indolic

Jasmine, lilac, honeysuckle, gardenia, and orange flower all have diverse olfactory profiles, yet they share the presence of indole, which gives them a rich, narcotic fragrance. Without this unique material, which in pure form looks like white diamond dust, it would have been impossible to recreate the true scent of blooming flowers. A tiny amount of indole is all it takes to infuse life into a composition of floral notes, to make an abstract, vague petally form to appear as a lush, nectar suffused flower.

Indole is often described as “fecal and animalic,” which is a complete misrepresentation. In its pure form, indole smells like moth balls, possessing the same heavy, sweet, tar-like pungency. In fact, it is so strong, suffocating and diffusive that smelling it pure one is hard pressed to imagine that it could be a lovely floral note. Yet, indole changes dramatically in dilutions. It suddenly displays its radiant, floral quality. The suffocating moth ball effect disappears to give way to a completely different image--a handful of gardenia petals or a branch of jasmine flowers.  The opulent, narcotic effect of indole is employed whenever a perfumer wants to create a floral effect or else to give a lift to a heavy, oriental composition.

For a beautiful indolic effect in a jasmine composition, Serge Lutens A La Nuit is my favorite choice. To see the interplay between indolic and animalic notes, Serge Lutens Sarrasins is a great example. As a side note, when jasmine is described as animalic, it is not the indolic notes that give it that quality, but rather other compounds reminiscent of horses. It turns out that jasmine and horse sweat share some of the same molecules.

On the other hand, fragrances like Chanel Cristalle, By Kilian Love & Tears and L’Artisan Parfumeur La Chasse Aux Papillons rely on a delicate touch of indoles to give radiance and bloom to their floral accords. 

Aside from fragrances, indoles are used to create chocolate, coffee and various fruity accords in flavors. For food preparations, it is used in trace amounts, yet the indolic presence is often essential to create a natural quality in imitation flavor accords.

Photo credit: White petals by Harry Chisling via flickr, some rights reserved.

Comments

[Olfactoria]

Very interesting. I can see the necessity of indole in perfumery, even if it is not my favorite note. I can do without heady flowers mostly. ;)

[iodine]

Seriously, indoles in high concentration don't smell fecal? I've always had blind trust in my Organic Chemistry book and teachear (I know it doesn't sound very scientific, but on my behalf I must say I studied Inorganic Chemistry at University, so never met an indole vis à vis!!)
Then, really indoles in La Chasse?! I'm wearing it today, deeply enjoying its radiancy, lightness, sunny-ness (it seems to contain everything I'm craving for in spring: linden, jasmin, orange flower, tuberose... I've been loving it since its realease but never ended up buying a full bottle).
Dear Victoria, these two informations upset me!
Thank you, I love your fragrance notes series.

[Elise]

I love your fragrance notes. I've been thinking about indoles a lot lately and this is wonderful information. Thanks!

[sweetlife]

Fascinating, V. So what do you think accounts for this (very common) misrepresentation? Is it an attempt to describe the effect of the material, rather than the material itself? Is it also a canard that indoles are found in both flowers and feces? Because I was kind of fond of that fact--it always reminded me of Neruda talking about piss and lilies.

Love, love, love the fact that horse sweat and jasmine share molecules. I really want to do a whole piece about these magical chemical correspondences.

(And thank you SO MUCH, btw, for telling us what it looks like in pure form. It may be childish, but it helps me to imagine things.)

[Victoria]

You point out an interesting distinction, B. Indole is not necessarily heady nor even used for a heady effect. It simply lends a natural quality to floral accords. Most of the time it does not even register as such. Atelier Cologne Grand Neroli, for instance, is full of indoles, but it is hardly heady.

[Victoria]

Don't get upset! :) Indoles are naturally present in jasmine and many other floral notes. They are essential in fragrances to give a natural floral quality, that radiant, sunny, vivid effect.

[Victoria]

You are welcome, Elise! I love learning that indoles are used in flavors too. Actually, many animalic materials like natural civet and musk used to be used decades ago in artificial flavors. Raspberry was commonly formulated with civet.

[Victoria]

I think that we just do not often get to experience these materials in isolation, that's all. It is very hard even for an experienced perfumer familiar with a large palette of raw materials to smell a fragrance and tell exactly what is contained in it. It is as if you were trying to describe the flavor of apple pie (sugar+flour+butter+apple+cinnamon) without ever having tasted these components separately.

You are right, they occur in feces, but mostly of other mammals. From what I read, beavers somehow produce more indoles. In perfumery, though, fecal notes like skatol and civet are classified as animalic, while indoles are in the floral group. Indoles are simply magical in how much they change when diluted. What smells like a moth ball suddenly begins to resemble soft, delicate flower petals.

Orange blossom and neroli contain more indoles than jasmine. So, they might be a good reference, even if one does not have an access to the pure raw material.

[maggiecat]

Fascinating and informative! Thank you! I'd been thinking of indoles as primarily fecal, which made me hesitant to try a scent labeled "indolic" but now I see that they're a major component of some of my favorite notes. I appreciate the clarification.

[sweetlife]

So--sorry to harp on this, but I'm fascinated--maybe the fecal/flower connection is so powerful as a metaphor (because, wow, it is) it sort of slips rhetorically into the description of the smell? That would make a lot of sense to me. I've seen lots of other rhetorical/metaphorical slips like that in writing that purports to be describing an objective reality.

And now I'm wondering if that *ripeness,* that funky touch of basenote rot that I smell in jasmine and orange blossoms on the vine and tree is indole, as I've always assumed, or something else. Because like Birgit, I've always assumed that the erotic headiness of those white flowers is due to indoles.

Someday we will all be paying tuition to hear you answer questions like these, V.

[Victoria]

Oh no, don't apologize, it is a fascinating point, and I am glad to explore it further. The fact is that indoles occur naturally in many products of decomposition--dead flesh, feces (yet, like I said mostly those of animals,) and this is the link that is often stressed. I mean, it is fascinating, isn't it? The fact that we are so draw to the scent of blooming flowers, while a chief component of their odor is that of death... You think about it some more and suddenly you are in the domain of Baudelaire and Les Fleurs du Mal.... It is simply a haunting thought in itself. It is much more alluring in that dark, subversive manner than simply thinking of indoles as smelling of moth balls. Although truth be told, the smell of moth balls kills me. In India, I have to fight with the hotel maids not to dump loads of moth balls into my room. There they are thought to be disinfecting and clean smelling!

On the other hand, the smell of decay is in itself very complex, and indoles are all but one part of it. If you smell an animalic, funky note in jasmine, it is mostly due to the presence of other compounds (para-cresols and other leathery-horse like notes). Yet, both indoles and leathery notes are essential to create a jasmine note. Orange blossom is mostly indoles though.

[Victoria]

I am glad to clarify! Indoles can be delicate and radiant, and a small hint of them is enough to make a sharp and fresh floral accord suddenly smell luminous and natural.
Of course, it also depends how indoles are dosed and what they are paired with. They are really quite fascinating.

[linda]

This really is interesting Victoria. Thank you so much for sharing the information. (I love your postings!)
I have heard that indoles are found naturally in many of the cruciferous vegetables such as broccoli and brussel sprouts. Perhaps that is why the cooking of them produces a smell that is offensive to some.
I am curious...the indoles added to fragrances...where do they come from? What is the procedure for aquiring them?

[sweetlife]

Yes, yes, the Fleurs de Mals thing, and flowers on the grave, and a thousand thousand other examples--that's exactly the rhetorical/metaphorical territory I'm talking about. It makes perfect sense that it would be powerful enough to take over simple reality. That kind of thing is rife in scientific literature about women's bodies and about death and illness, too. Our metaphors and the specific cultural ways we have of understanding things run away with us, though scientists are always very irritated when I point this out. :)

I think, as humans, we are always longing for connections between death and life, growth and decay, even as we want them to be opposites. The Neruda I mentioned above is from his essay "Toward an Impure Poetry," in which he offers poetry as a way to reconcile those impulses: “Let that be the poetry we search for: worn with the hand’s obligations, as by acids, steeped in sweat and smoke, smelling of lilies and urine, spattered diversely by the trades that we live by, inside the law or beyond it.”

And now, having written a whole other post in your comments section, I will cease and desist (but not stop thinking!).

[Elisa]

Thanks so much for clarifying this point about indoles -- I find many jasmine fragrances animalic but I won't attribute that quality to indoles anymore.

I always think that white flowers, especially orange blossom, have a prickly quality -- the closest thing I can compare it to is the pins & needles sensation when your foot falls asleep. As though you were experiencing the smell in a pointillist fashion. I think this must be related to what Luca Turin calls "the back-of-the-throat rasp" of indolic white flowers.

[Victoria]

Elisa, you've hit the bull's eye with that prickly quality description. That's precisely the indole effect for me too. That kind of raw silk grating sensation when it is used with a heavy hand. Diluted, it becomes surprisingly delicate and soft.

[Victoria]

I am very glad that you liked it! :)
That could be true, although I think that the offensive smell of cruciferous vegetables is mostly due to the sulfuric compounds, rather than indoles.
Indoles occur naturally in coal tar, and that tends to be the main industrial source.

[sweetlife]

Thank you, Elisa! I have been calling it "dusty" to myself, but haven't been satisfied with that...

[Victoria]

Thank you for this beautiful thought! I will in turn share with you my favorite poem from Fleur du Mal, Le Flacon:

Ou dans une maison déserte quelque armoire
Pleine de l'âcre odeur des temps, poudreuse et noire,
Parfois on trouve un vieux flacon qui se souvient,
D'où jaillit toute vive une âme qui revient.

Or in a deserted house, some cabinet
Full of the Past's acrid odor, dusty and black,
Sometimes one finds an antique phial which remembers,
Whence gushes forth a living soul returned to life.

A related thought in a different form...

[mandy aftel]

just last week i was explaining indole to michael pollan who visited my studio and i had him smell the absolutes of jasmine, honeysuckle and orange flower in rapid succession to find the indolic common thread.

[Victoria]

Fascinating! Was he able to find it in the end?

[Mandy Aftel]

yes, he was and I had never thought of explaining indole that way. I found it a thrilling way to explain it -- I was lost trying to do it in words. I am so impressed with the way you write about in this piece.

[Marina]

Mmm, indoles :)

[Victoria]

Mandy, thank you, such a nice compliment coming from you means a lot.

[Victoria]

I knew that you would enjoy this! :)

[Dionne]

This kind of post is why I enjoy your blog so much, Victoria. Being the science-geek that I am, I love how perfume is such a fascinating crossroads of science and art. Since I tend to live in my head, the beauty of these smells is a great way to bring me back to my physical self, but keep my mind engaged as well. Smart AND pretty. ;)

[Olfactoria]

That is even more interesting! Clearly I have not enough technical knowledge to make a distiction here, so it is not indole I do not like but the white flowers themselves? Because as you know, I adore Grand Neroli, but I run from something like Fracas.

[Victoria]

Fracas is not particularly indolic to me, but it sure is heady and milky. Tuberose, for instance, is a heady floral note, but what gives it that rich, heavy quality are the milky, coconut notes.
If you like neroli, indole is not what bothers you in other white floral blends.

[Victoria]

Smart and pretty is the best combination! :) Thank you, I am glad that others find this topic as interesting as I do.

[RH]

Wow, I enjoyed reading both the article and all the comments here. Thank you so much for this! I guess I won't be running from the description "indolic" anymore...

On a slightly different note, I kind of like the smell of mothballs. I'm not swooning over it, but I don't mind it, and sometimes it brings me back some nice memories.

[Victoria]

Oddly enough, as much as I tend to complain about moth balls in India, once I get home and if I ever get a whiff of mothballs someplace, it makes me very nostalgic.

I am glad that you liked the post (and I am with you, I love what others shared here in the comments, such interesting perspectives.) I feel that the more one knows on the subject, the more one can appreciate it. I am wearing Atelier Cologne Grand Neroli right and enjoying its indolic, raw silk richness.

[March]

Baudelaire night, from my favorite, L'Invitation Au Voyage:

Des meubles luisants,
Polis par les ans,
Décoreraient notre chambre;
Les plus rares fleurs
Mêlant leurs odeurs
Aux vagues senteurs de l'ambre,
Les riches plafonds,
Les miroirs profonds,
La splendeur orientale,
Tout y parlerait
À l'âme en secret
Sa douce langue natale.

Furniture that wears
The lustre of the years
Softly would glow within our glowing chamber,
Flowers of rarest bloom
Proffering their perfume
Mixed with the vague fragrances of amber;
Gold ceilings would there be,
Mirrors deep as the sea,
The walls all in an Eastern splendour hung -
Nothing but should address
The soul's loneliness,
Speaking her sweet and secret native tongue.

[Persolaise]

Thanks very much for this post.

The only thing I've got to add is that if one of the tiny little crystals somehow goes astray, your house will smell of mothballs for days!!!

[Victoria]

Oh, March, thank you so much for this! Such a beautiful poem! To think that we went from indoles to Baudelaire with such ease in this thread! :)

[Victoria]

How true! Whenever I have to weigh indole out to make dilutions, I find that I smell this moth ball odor for hours, if not days! It is so potent.

[Lucy]

Is this the element that produces the cloy factor?
So interesting and informative. I must say that I have been reading your site for a long time, because it is an education in perfume and so much depth. I so enjoy your innate tone of calm and balance that somehow still shines through all the passions and enthusiasms. Your writing is informative and soothing at the same time.

[Lucy]

My proofing skills are not what they could be this morning! I meant "have so much depth". And precision -- quite a feat in the description of perfume.

[Victoria]

Indolic notes are not really cloying, they almost give a textural sensation--of raw silk, that kind pleasantly rough note.

Thank you for your kind words! I am very touched and of course very delighted to hear that I manage to maintain some calm and balance. :)

[Saintpaulia]

Victoria, I am getting in on the tail end of these essays of yours, judging by the dates. So, though a Johnnie-come-lately, I wanted to tell you anyway that you and Luca Turin are my two favorite writers and interpreters of fragrances. And this is high praise in my book as I cut my teeth on Luca. You two are completely different of course, but both of you are delightful.

[Victoria]

Thank you very much for such a nice compliment! I have always admired Luca's work for his ability to decipher fragrances and convey his passion. I am glad that I can contribute a bit myself.