Friday, December 7, 2007

Leather Series 3: Production

Rendering a leather note in perfumery is a challenge for the perfumer who must coax this difficult and cult note into submission to make it sing with the rest of the composition. Production relies on two different courses: naturally derived and synthesized in a lab. Both account for a potent aroma of smoky and alteratively drier or sweeter notes, characteristic of the cuir family.

Let’s see what is actually used.

The naturals:

Birch: Betula Alba, the tree known as birch, owes its name to the Latin verb batuere meaning to strike. It is no coincidence that the branches of birch have been used for corporal punishment. Traditionally used in tanneries in Russia, Finland and Northern Europe in general, its bark produces birch tar and resin, an intensely wintergreen and tar-like odour, which has been used in Cuir de Russie type of scents in the distant past. The oil is widely used in suede and leather tannery in Russia and the essence obtained from birch buds is used for hair tonics and some cosmetic products.

Juniper and cade oil:
Juniper trees produce dark viscuous oil (cade) upon getting burned which possesses a smoky aroma that reminds one of campfires in the forests. Also used in Cuir de Russie type of scents in the past along with birch. It additionally has an anti-mould property which explains why it is a prime material for the binding of books, surely prone to decay and deterioration otherwise.

Styrax: Liquidambar Styraciflua and Liquidambar Orientalis trees are used for their excretion of the sapwood obtained by pounding the bark of both varieties. L. Styraciflua comes from the Americas (in particular Honduras, Guatemala and Mexico), while L.Orientalis comes from Asia Minor. The essence used in perfumery to give a leather undertone comes from the Honduras and is purified with volatile solvents or through vacuum distillation.
Styrax notes are usually sweeter than those of birch when used for leathery notes.

Cassie: The bark of cassie, a tree that belongs to the family of mimosa, and the absolute from the flowers are also used for giving a deep, intense leather note in some perfumes based on natural essences.

Castoreum: The secretion from the glands of beavers from Russia and Canada is a very intense, repulsive odour that when highly diluted can provide a leathery scent to fine perfumery. A by-product of the fur industry, it has been prized in perfumery for its tremendous fixative powers and its deeply animalic edge with a dry quality that smells like real leather.

Another natural essence that can produce a leather note although not usually used as such is Myrtle. Because of its camphoreous, green, rather than pungent leathery aroma, it is not the preferred choice for rendering a leather note in perfumes; although it is used in tanneries for the curing of hides.

Last but not least, cistus labdanum can provide a leathery backdrop- in cases where a more smokey/ ambery note is required ~such as in Caron Tabac Blond, Serge Lutens Cuir Mauresque and Ava Luxe Madame X {click for review}.

It is important to note that natural perfumers can render leather notes in their perfumes through the combined use of different essences such as black tea, patchouli or tobacco in addition to the above; sometimes opting for ethically avoiding animal products (castoreum) altogether.

The synthetics:

The major revolution in the production of leathery notes in perfumery came in the 1880s with the apparition of quinolines, a family of aromachemicals with a pungent leather and smoke odour that was used in the production of the modern Cuir de Russie scents appearing at the beginning of the 20th century such as Chanel’s (1924) as well as in Caron’s Tabac Blond (1919), Lanvin’s Scandal (1933) and, most importantly, Piguet’s Bandit (1944).

The chemical name of the ingredient primarily used from the quinolines groups is 4-(2-methylpropyl) quinoline, commonly referred to as isobutyl quinoline. A colourless to pale yellow liquid, used in a dilution of 1.00 % solution or less, it possesses a fiercely potent odour profile described as earthy, rooty, and nutty, echoing certain facets of oakmoss and vetiver and blending very well with both. Isobutyl quinoline also has ambery, woody, tobacco-like undertones: a really rich aromachemical! Its character can be very well perceived in the above scents as well as Cabochard by Gres.

Another synthesized note is the suede accord: a much subtler, more velours deep feel in the realm of leather notes. Less aggressive, suede notes are created in the laboratory for modern fine perfumes such as Lutens’ Daim Blond and Donna Karan. The origins hinge on muscone in the past or a complex tactile evocation of suede through a secret formula for more recent examples.

To a lesser degree the safraleine aromachemical can add a leathery tinge to perfumes. Evident in isolate of saffron, safraleine has an interesting smell ~ a combination of shoe polish/black cherry/air conditioning refrigerating fluid.

Aldehydes and especially C10, C11 and C12 are also used in addition to other ingredients in leathery perfumes to round out the composition and make it smooth.

Last but not least, in an effort to find materials that would enhance or augment leather tones and provide a cheaper and more stable alternative to animal-derived castoreum for rendering leather notes, the US Patent 4528124 (Jul, 1985 Sturm et al.252/522) has been proposed as a solution. The compound having the structure ##STR2## is a known compound disclosed at Chemical Abstracts Volume 99, Monograph 139339e. As I haven't smelled this secret ingredient I cannot report back on its effect, but it worth mentioning.

The search for materials which can provide a more refined leathery and castoreum aroma profile apparently continues.

Next instalment will focus on a scent fit for kings.

Pic of birch forest, Birch Hill Fairbanks in Alaska by Jeff Breu courtesy of Google images


  1. Anonymous17:08

    I had no idea that birchwood had any correlation with leather fragrances - when I saw it, I always thought it had a 'woody' aroma not a tar-like one.

    In fact on Basenotes, we had a small discussion about Patchouli 24 (Le Labo) and the birchwood in it that smells to someone like aoud.

    Great article - as always.

    1. Birch is not just the birch itself, but also birch tar too, which is sometimes used to enhance any leather accords as some dryness, dustiness etc..

  2. M,
    Thanks for the touching compliment.

    Indeed birch is a classic ingredient in leathers.
    I will have to go look at the discussion on Basenotes, sounds interesting. Of course it might also contain some aoud, don't knock it! (they don't always list everything, right?)

  3. Anonymous00:15

    Yor articles have given me a new appreciation of leather as a note in perfume. Thank you. Looking forward to "scent fit for kings".

  4. Thanks Joan. Leather is a peculiar thing in fragrance; worth exploring.

    Stay tuned!

  5. isobutyl quinoline, safraleine, oudh really all do smell like leather. Iso Q is one ingredient that I find most difficult to work with since I have the purest form of it. It's one I've been meaning to dilute to make it more "user friendly". I know it's been used in a lot of perfumery classics you listed in this article. I hope soon I will make something with it. Birch tar oil if used sparingly along with styrax can smell very much like leather. Castoreum smells to me like a very raw form of leather. I like this particular note and once again, needs to be used very sparingly or it could ruin a fragrance like Iso Q. Cassie, that's an unusual one to bring up, never thought much that it smelled like leather. But I do use in Pillow of Flowers and I've been asked if I had put leather in that scent of mine by one person. I guess that note with the aldehydes gives Pillow of Flowers a very slight hint of leather when there is not and it wasn't my intention of making it leathery. I wanted it to be a big white floral which it's supposed to be. Oh well, all smellers of scents are smell things so differently. It's all subjective in the end. Juniper and cade oils. Hmm...these I need to get a hold of. I have juniperberry essential oil but it smells mostly like gin and is very green to me. I like Juniperberry essential oil. I'm working with it now on a scent that I want to make. Not yet there on how I want it.
    I enjoy these passages into the inner workings of the Leather scent. Some of it I knew about but as always, some of it I didn't which is very good. It's always good to learn something new that you didn't know before about stuff.

  6. Is it birch that gives the sharp, "bracing" element to a leather accord? I find that real leather has a sort of fresh, cold scent that floats above the basic animalic one. I especially like leather fragrances that emphasize that quality, rather than the funk.

  7. Birch really is bracing. It is very medicinal in quality too. It's another that has to be used in very minute quantities or you end up with a scent that smells like Vapo-Rub. I used both Birch and Styrax prominently in my scent, Kitsune.

  8. Dear Armando,
    thanks for your compliments and for your very interesting comment.

    This is the second time I hear aoud being mentioned as smelling like leather: I must investigate this, as I have classified it in my mind as the quintessential musty smell, LOL!

    It's interesting that someone commented on PoF as being leathery. I perceive it as very soft, buttery, smooth. But right you are, perceptions are individual.
    IsoQ is very potent stuff (same with castoreum). I am sure one needs to dilute to great percentages.

  9. Dear M,
    I like the "cold" quality myself about nappa leathers especially. I think Bandit interprets this cold thing well. It's very green too which helps.

  10. Kitsune is on the list to be mentioned in the future, so it's good to know from the mouth of perfumers! Thanks!

  11. cassie - Acacia farnesiana, related to mimosa (Acacia dealbata), the flowers are used and have a mimose-violet note.
    cassia - Cinnamomum cassia or the chinese cinnamon, the bark is used and has a strong spicy note.

    another material: Suderal (IFF), it smells like pure suede! (like Daim blond)

  12. Octavian, thank you again for providing your knowledge.
    I got the info on Cassie from natural-sourced texts.

    I didn't know about Suderal though, at all! Do you think it was actually used in Daim Blond or is it a registered material for the use of IFF only (in which case I hypothesize it was used in DK?)

  13. Choya Loban, a destructive distillation of benzoin resin, also gives a smoky/leathery aroma. It too is very strong and needs to be greatly diluted.
    Another oil that has a leathery aroma is fossilized amber, another destructive distillation. It is a bit more elegant than the choya loban.
    I find it unusual that styrax and cassie are used for leather notes, they dont smell 'leathery' to me at all. Styrax really smells more floral to me, with bits of spice and balsams, it very much reminds me of hyacinth. And cassie smells like a honeyed floral.

  14. Gabriel09:29

    You left out a natural: the oft-ignored costus root. This wonderful essence smells exactly like freshly tanned leather. Its longevity doesn't compare to things like castoreum and birch tar however.

    Birch tar's wintergreen aspect seems to vary a lot between noses. To mine it is intensely sweet and a rather unpleasant addition to drier notes.

  15. Hi! Brand new here and I stumbled on your blog by accident..
    Birch Tar seems to appeal to some and not so much to others. It reminds me of burning wood, so I use it in my Christmas inspired scents. Gonna have to check the others out! I love leathery scents. Perfect for the southern cowboy scents I'm working on.
    Great blog! Gonna go poke around a bit..

  16. Great post! Brand new here and I'm just poking around:) birch tar seems to appeal to some people and smell disgusting for others. It reminds me of burning wood... Which is why I use it in my Christmassy perfumes! Leather is such a beautiful smell to work with.. Great for my cowboy scents!
    Great post. I'll keep on creeping around.

  17. Brian04:47

    Gabriel, I agree about costus. I too think it really adds to a leather note. In fact my leather accord contains costus, along with choya loban, castoreum, and oakmoss.

  18. So that great smell of a Balenciaga bag isn't actually the leather, but something they use to treat the leather? Hmm, I would love to know what notes they use on them!

  19. S,

    I suppose you should ask at the workshop manager, though sounds complicated too...


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