RESINS: BENZOIN

It’s time to get back on track with Materials Wednesday and finish up the series on resins. I’ve written before on myrrh and mastic, but somehow missed one of the important resins, benzoin. This material is used extensively in perfume, mainly as a fixative; it is also used medicinally,  and burned as incense. In other industries, benzoin is used to enhance and fix food flavorings, especially vanilla, as a chewing-gum base, and to flavor tobacco. It is sometimes used in the manufacture of varnish.

Benzoin is the gummy resin obtained from trees in the genus Styrax, mainly Styrax tonkinensis, which grows in Southeast Asia. Benzoin is also known as “styrax” “storax” or “Siam benzoin”. The raw material is harvested in much the same way as other resins, by making cuts in the trunk of the tree, waiting until the sap runs out and solidifies, then scraping the “tears” off of the tree.

Because benzoin is an important commercial product, efforts have been made to study and improve methods for its cultivation and harvesting. There are now Styrax plantations, so benzoin is not in as much danger as some other materials that are still harvested from the wild.

The scent of benzoin resin is mildly sweet and, of course, resinous, and bears some similarity to vanilla. Because the scent is mild, it is a little hard to pick out of a perfume mix, but it does lend its own subtle signature to a blend. A lot of my perfumes contain benzoin in various concentrations.

Benzoin resin comes as a solid, which can be burned as incense or tinctured. When burned as incense, a magical transformation occurs and the smoke creates a powerful scent that is very different from the raw resin, absolute, tincture, or other preparation for use in perfumery. The beautiful, characteristic scent of benzoin used as incense is especially startling the first time you burn it, if you are used to smelling the tinctured or otherwise treated resin. It is unlike any other form of incense, and is one of my favorites.

For perfumery, benzoin can also be obtained as an “absolute”, which is generally pre-diluted with alcohol. Although this dilution makes it pourable, it is still dense and sticky, and cleanup is not fun. The hassles of working with benzoin aside, it is a useful material that I like having in my main selection of basic perfume-building blocks.

[Benzoin resin on tree trunk from Givaudan website, although it seems to be a cropped version of a photo from Accademia del Profumo, or from a website on “securing the future of benzoin in Laos”, or from some other ambiguous source. It seems to be very popular. Benzoin resin clump from an essential oil vendor’s website; Styrax trees image from an Indonesian commerce promotion website, Styrax flowers and botanical drawing from Wikipedia.]

MATERIALS: FRANKINCENSE AND A GIVEAWAY

From elemi, the obvious place to go is frankincense. I wrote a post on frankincense back in 2010 when I started this blog, but it wouldn’t hurt to do an update. Frankincense, also known as olibanum, is another resin that comes from trees in the family Buseraceae, in this case Boswellia. The resins used in incense and perfumery come from several different species, each with its own aroma profile, and each species yielding a slightly different scent depending on origin. Boswellia is native throughout arid landscapes in India, North Africa, and the Arabian Gulf regions. 

The trees themselves are, to me, very attractive, typically with gnarled trunks covered with smooth bark that peels as the tree grows, and sparse, lacy leaves. Boswellia trees are deciduous, losing their leaves during times of stress, typically during the dry season. Resin is obtained by making shallow cuts in the bark of the tree and harvesting the dried resin. Oil is obtained by distillation, although the raw resin can also be tinctured.

I am growing seedlings of several different Boswellia species: dioscoridis, neglecta, and carteri. Given my propensity to under-water or just forget to water, they seem to do well in my hands. The carteri is the largest one, and has kept its leaves this summer. The other two have lost theirs because they’re small and in a very hot, dry location. They’ve done this before, so I know they’ll perk up and grow when summer is over.

Frankincense is one of those materials that I’m worried about. Although it’s listed as “not threatened”, the trees can only produce so much, and it’s likely that their habitat is diminishing due to the same sort of reckless human activities that are destroying nature everywhere. Boswellia seedlings are eaten by domestic animals, trees are burned by fire, they are cut down to clear land or to use for firewood or lumber and, of course, over-harvesting of resin weakens trees. I keep my stash of resin and oil against the day when these things may no longer be available, or when the price has risen because supply cannot keep up with demand.

Boswellia is a traditional Ayurvedic medicine reputed to have strong anti-inflammatory properties as well as anti-microbial, anti-fungal and insect-repellant properties, yet another example of trees producing compounds that help keep them healthy and infection-free.

The species that produces the “lightest” and greenest oil is B serrata, which grows in India. This oil is closer to the citrusy-green scent of elemi than the others, and very much in the direction of pine needles. The primary constituent is alpha-pinene (over 70%!), with small amounts of limonene, verbenol, pinocarveol, myrcene, borneol, para-cymene, and other trace molecules. I used Boswellia serrata oil in Gujarat along with B carteri to provide a light incense note to go with the smoke element of the scent.

Boswellia carteri is the most common species used for the production of resin and oil. The scent is very different from that of B serrata, much richer and more resinous. Alpha pinene makes up less than half of B carteri oil, the main constituents being diterpenes whose long chemical names you really don’t want to see, although if you’re really curious you can view them here, and octyl actetate, which has a distinctive fruity smell. I have used Boswellia carteri oil in a number of my perfumes, most notably the Devil Scent series, where it was used to give a vague impression of burning incense. I also use it, along with natural sandalwood oil, in my Body Balm.

This is getting long, so the post on the different types of Boswellia will probably be continued next week.

Leave a comment about what type of frankincense you like, or what frankincense-containing perfume(s) you like and be entered in a drawing to win a 5-ml travel spray of the Devil Scent of your choice plus some extras.

[All images are from Wikimedia]  

WEDNESDAY MATERIALS: ELEMI AND A GIVEAWAY

One thing leads to another. Last time I wrote about galbanum, and that post leads to other resins, so what I think I’ll do is go through the resins that I use or have in my collection of things I might use.

Elemi comes from a tree called Canarium luzonicum, which is native to the Philippines. It belongs to the family Burseraceae, which includes frankincense, myrrh, and other resin-producing trees, some of which I am trying to grow in my greenhouse.

Apparently a number of different resins have been called “elemi”, over the years, including those from other Burceraceous trees and shrubs such as Boswellia and Icica species, so it is not clear what sort of “elemi” was the one reputedly used for incense, skin care, and embalming in ancient Egypt. It seems unlikely that the Egyptians visited the Philippines to obtain Canarium resin when sources of Boswellia (frankincense) and Commiphora (myrrh) were closer to home. 

Canarium trees grow quite tall, and are attractive with their canopy of broad leaves and almond-shaped nuts. The resin is most plentiful during the rainy season, and trees are “tapped” then by making cuts in the trunk. The resin is steam distilled to produce elemi essential oil. Elemi oil has antibacterial and antifungal properties as well as a good smell, so probably functions as one of the tree’s defense mechanisms.

Elemi, although resinous, has a light, clean lemony-green scent with resinous nuances. This is not surprising given that limonene makes up more than half of the constituents of the oil. Alpha-phellandrene is the other major constituent, along with elemol and small amounts of other molecules, including alpha-terpenol, alpha-terpenolene, sabinene, and elemicin. Alpha-phellandrene is also a citrusy odor, so it is the resinous-woody elemol and spicy-floral elemicin that gives it that little extra resinous something that makes it elemi.  Incidentally, all of these components are available as pure aroma chemicals, so it should be fairly easy to come full circle and re-design a synthetic version of elemi if one wanted to do so.

Elemi is a good go-to oil if you want fresh, green, slightly resinous top notes in a perfume. I used it in Blackbird and Bat to provide a clean resinous note from the beginning, and will likely use it in many more compositions.

Do you like resinous notes in perfume? Which resinous notes and/or perfumes do you enjoy most? Leave a comment and be entered in a drawing for a 5-ml spray bottle of Olympic Orchids Blackbird along with some other miscellaneous surprise goodies. 

[Canarium tree photos are from the University of Southern Illinois Phytoimages pages; resin and Canarium tree-tapping images from retailers' websites; Blackbird bottle photo is mine.]

SCENTS OF GRASS: THE CYMBOPOGONS

Last week’s materials post was on vetiver, so this week’s will continue with three related grasses that are used in perfumery and other aromatic applications, Cymbopogon citratus (lemongrass) Cymbopogon nardus (citronella) and Cymbopogon martini (palmarosa). Like vetiver, these are all in the grass family, growing as big clumps, but for the Cymbopogons, the essential oil is derived from the tops of the plants, not the roots. All of these species were probably originally native to India and/or Southeast Asia, but have become widespread throughout warm parts of the world due to culinary and agricultural uses.

Lemongrass is most commonly thought of as a food flavoring due to its extensive use in Asian cuisine. Lemongrass oil is obtained by distillation of the green parts of the plant, with most of the aroma contained in the base rather than the outer parts of the leaves. I think of lemongrass imparting a delicate flavor to Vietnamese cuisine, and working well with coconut-based curries. The essential oil contains citral, limonene, citronellol, geraniol, and many other molecules that have insecticidal properties and mosquito-repellant properties, as well as medicinal properties, especially anti-inflammatory and anti-fungal activity.

Lemongrass essential oil has a characteristic, unmistakable top to mid-range scent that can be quite heavy, strong, and overpowering if used in perfumery, so needs dosing with a light hand and with the proper accompaniments. Given that most of the lemongrass constituents, and all of the main ones, are available as pure aromachemicals (that’s for another post!) the perfumer has the option of creating a unique “lemongrass” accord to use, or choose which aspect of it to emphasize in a blend.  I used lemongrass essential oil in Kyphi, but I think if I used it in another blend I might opt for a lighter reconstruction that’s more like the flavor one gets in delicate lemongrass-flavored cuisine.

Citronella, the evil cousin of lemongrass, contains large quantities of citronellal, citronellol, geranial, limonene and other “lemony” molecules. It is an important source of these and other isolated aroma chemical molecules. Like others of its genus, it looks like a small clump of pampas grass, not a very attractive sight. Perhaps the best known use of citronella is as an insect repellant, with citronella candles traditionally burned to keep mosquitoes away from outdoor gatherings and to scent insecticidal sprays. Because of this association, in my opinion, citronella does not work well in perfumery. Who wants a perfume that smells like bug spray? Having said that, the aroma molecules obtained from citronella have a multitude of uses in perfumery, and are probably present to some degree in the majority of perfumes.

Palmarosa is yet another one of those plants that looks like pampas grass. The green part of the plant is distilled once it has flowered,, but plants can live for many years, regrowing the parts cut for distillation. The essential oil contains mostly geraniol and geranyl acetate, along with linalool, myrcene, farnesine, and ocimene. As in the case of other essential oils, the reported percent of constituents, and the constituent profile itself varies depending on whose publication you read. Apparently the composition differs depending on which part of the plant is used, and I’m sure it also varies by season, harvesting techniques, and distillation techniques. 

Palmarosa essential oil smells sort of like a mixture of rose geranium and lemongrass, not too surprising given that it’s a Cymbopogon. It seems a little sharp and raw by itself, and I have not used it in a perfume. I can see how it could work as an excellent substitute for rose geranium. However, I can’t see how it would work as a substitute for rose, although it seems that it has commonly been used to adulterate rose oil or absolute. It is reported to have antiseptic properties and to be very good for the skin, with “anti-aging” properties. I’ll have to try it in my formula.

[All plant photos are from Wikimedia; product photos are from retailers' websites. I see one of them used the Wikimedia palmarosa image in their advertising.]