Vetiver and its derivatives

An elegant indispensable wood

Vetiver (or vetyver in the old French spelling) in all its forms is a material derived from the harvested roots of a tall grass, Chrysopogon zizanioides. The essential oil is used in classics such as Coty’s original Chypre (1917), Chanel N°5 (1921) and Guerlain’s Mitsouko (1919) as well as many more, even when a woody theme is not present.

Unlike other natural products, it is difficult to replicate the effect of vetiver by means of synthetic substitutes in the form of individual materials or bases. This is partly owed to the fact that the smelling principle was until recently not understood, that is, the constituent molecule(s) primarily responsible for its signature odor and effect in compositions. In 2020, Philip Kraft and other researchers ascertained (+)-2-epi-ziza-6(13)en-3-one to be the smelling principle, a molecule with a detection threshold of 0.029 nanograms per litre air. (The detection threshold is the concentration in air at which it is recognised, usually the average of a number of panellists. The lower the threshold, the easier to detect.) For perspective, the odor threshold of the genuinely fecal molecule skatole is 0.327 nanograms per litre air, an order of magnitude higher.

I will not get into technicalities here but it should be noted that a low odor detection threshold does not always translate to our idea of an odorant being potent. For that, it must also evaporate easily, which corresponds to a high vapor pressure.

I would like to draw attention to the beautiful varieties of vetiver available in the palette. The Haitian kind is most well known, but vetiver is also available from Java where it is noticeably smokier than the Haitian product. Vetiver is also grown in India, where it has a noticeably warmer scent profile with a spicy note and less of the grapefruit top note. India also grows vetiver in sand — there is a Givaudan captive natural vetiver that is also sand grown, and they both share a mineral facet. A Brazilian product is also sold and I am particularly fond of the oil from Madagascar for its rooty, almost parsnip like quality that is perfect for vegetal, earthy or forest notes.

Of note are two other products derived from the oil: vetiverol and vetiveryl acetate. The vetiverol, in the same vein as patchoulol, is the heart of the vetiver oil and has less top note impact than the oil, though in moderate quantities depending on the structure, vetiver is quite low lying and may not touch top notes anyway. Vetiverol is noticeably cleaner in profile, generally less smoky and earthy.

Finally vetiveryl acetate is the acetylated vetiverol. It has a diluting effect in composition compared to vetiver oil, but it is useful and widespread in formulas, albeit less so today because of the price. It made up some 15% of the original Calèche by Guy Robert for Hermès, a monumental aldehydic woody chypre. Nevertheless price aside, its use is restricted to 0.9% of the final product today, which means for a 20% eau de parfum concentration, at most 4.5% in the formula. It predates the newer woody aromachemicals of the late 60s onwards like Vertofix, which began to serve the purpose of diluting woody materials to be used as large brushstrokes, though not to the extent of say, Iso E Super today. We do find over 60% Vertofix though in the discontinued Hermessence fragrance, Paprika & Basil by Jean-Claude Ellena.