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Fragrance in Roses: Odors That Induce Passion

With the upcoming commercial date for expression of love just around the corner, I thought it would be interesting to explore some of the science behind the various aspects of love this week. Some articles shall be written by me, others will be excerpts of other's work that I comment upon. Here is an anticipated list of topics:

Monday - Fragrance in Roses: Odors That Induce Passion
Tuesday - The Biology of Copulatory Behavior
Wednesday - Why Women (Especially) Crave Chocolate from a Biological Perspective
Thursday - Zygotic Growth and Development

I hope you enjoy these essays.

The first essay is one that was written by Bob Hatterschide and was first published on the American Rose Society website. His essay is in italics, and my comments/additions are in normal print.

Fragrance in Roses
By Bob Hatterschide - an ARS Award of Merit article from 1995

The enticing, lovely fragrance of our beloved rose is a surprisingly complicated thing. We appreciate it by means of our olfactory senses, which, unfortunately, border on being capricious as far as consistency and repeatability from one individual to the next. This being the case fragrance is not one of our regular items on the judging list. Even you and I do not sense fragrance the same way, day to day, so that, when we do judge it, we often employ a sight-impaired person hoping that the decrease in one sense might be augmented in the case of the other.

The chemistry of rose fragrance is likewise a complicated mixture of what the old-timers liked to call "essential oils." Foremost among them is Rhodinol, which, as one might imply from the name, is essentially "rose" in character, the wonderful aroma of what we like to term "old roses." Add to that Geraniol, the familiar scent of geranium foliage, Nerol, the essence of magnolias, and, especially in our more modern yellows and oranges, Eugenol, the spicy fragrance which we all know as oil of cloves. Along with many other minor ingredients is a large helping of a relatively simple compound called phenyl ethyl alcohol, which is quite "roselike" in character, but in a dilute, rather receding way. Because it is a relatively easy compound to manufacture from inexpensive ingredients, it finds its greatest use in cheap perfumes, and more so to give Rose scent to household products where the use of precious Attar of Roses would fall into the "casting pearls before swine" category.

Rose fragrance is exuded from glands on the lower petal surfaces, and its amount is limited by both the variety of the rose and by climatic conditions. Sun and warmth are needed for maximum production. Check it out. Roses are never as fragrant on a cloudy day as on a sunny one.

So, how do we save and preserve this precious fragrance? History tells us of rose petals being strewn over ponds and piled so deep around Roman banquet tables that guests literally waded in them. That, of course, was only short term, but no doubt the early rose merchants loved it!

Two methods came into use, and these all within the last several hundred years. The first method, called "enfleurage" was a painfully tedious and labor intensive method, which employed what looked rather like picture frames, with only the glass in them. The glass was smeared with rendered fat, or tallow, and the individual rose petals placed on those surfaces one by one, allowed to remain a day or so while the oils were absorbed by the tallow, and then replaced by fresh petals. After several weeks, the fat, called a "pomade" was scraped off, and replaced with fresh fat. Meanwhile the tallow was extracted with pure grain alcohol, which separated the fragrant oils from the fat. After allowing the alcohol to evaporate, what remained was the intensely fragrant attar, known as an "absolute of enfleurage." Sounds like slave labor.

Another more common method took place right in the rose fields, using a process of steam distillation, done to prevent loss of quality by having to transport the petals any great distance. A large copper vessel was filled with a quantity of petals and of water. The top of the vessel was a rudimentary distillation apparatus with a vertical pipe followed by a downward turned pipe out of which the distilled materials flowed. It was air cooled as there was no water nearby to cool it. Ordinarily, a charge of petals was steam distilled twice, the first distillation, or first water, being deemed the best. Out of that arose an old expression for anything that was termed the better of several. The rose oils collected on top of the distilled water as a yellow-green waxy mass. This, like the previous method, was extracted by pure grain alcohol to produce the absolute. Again a great deal of manual work, and this time, the ever present danger of burning the petals and ruining the material.

Let me give you an idea of why this attar of roses has always been so expensive. A typical load for a still was 50 pounds of petals and four to five times as much water. About one-third of the water was collected as "first water" from each still, then the remainder was combined in another still to yield more material, usually of lesser quality.

It is estimated that about 500 kilograms of petals are needed to produce 1 kilogram of that waxy stuff, known as a "concrete,"which in turn yields only 500 grams of the absolute, or attar, meaning a return of only one-tenth of one percent on the amount of roses invested.

Because the attar lends such an exquisite finish to fine perfumes, and is highly desirable, the cost of attar is astronomical and in fact, for many years, was the source of monetary stability for the Bulgarian nation, even as we depended on gold for the same effect. Containers of it were stored in vaults!

In more recent times, advances in the chemical industry have provided for cold extraction of the petals directly, with subsequent vacuum evaporation. This permits operation at room or lower temperatures, thus insuring against degradation from heat.

The principal rose growing area of France developed near the town of Grasse, in the south, where huge fields of 'Rosa Damascena' produced thousands of tons of rose petals, producing attar valued in millions. 'Rosa Alba' has enjoyed some use, but it contains less essential oils, and is used primarily as a screen planting, to protect against excessIve wind damage. 'Rosa Centifolia', which had plenty of oil, proved difficult to extract by steam distillation, though I venture to say that modern extraction methods have solved that problem.

From the beginning of history, man has venerated the rose and associated it with all manner of good things. Homer wrote in the Iliad that Aphrodite anointed the slain Hector with rose oil and another ancient myth relates the story of a young girl who presented the goddess Venus with some lovely roses. When an unsightly disease threatened to mar the young woman's beauty, the goddess prescribed an application of roses, and of course, so the story goes, all was well.

Of equal importance to our ancestors was the association of that which smelled good with that which worked curative powers over bodily ailments, and the rose took a prominent place in this pharmacopeia. One reason for the preservation of the rose species is said to be the cultivation of roses within monastery walls by the monks. The preservation of dried rose petals as sachets was meant to release the fragrance of summer amid the cold of winter. It is interesting that the original method of making potpourri was by fermentation, which, accordingly, gave it the name, which means "rotten pot."

The association of roses with religion is as old as religion itself and found particular affinity with the Virgin Mary, whose many manifestations have frequently been reported as being accompanied by showers of fragrant rose petals. The very term rose window shows the affinity of the flower with liturgical symbolism, and many stained glass scenes of the Blessed Mother and other Saints show them holding roses. Underlying all of this was that association of fragrance with what is good.

What about those allegations that modern roses have no fragrance? People used to like to point the finger at 'Frau Karl Druschki,' and call her a soulless beauty for lack of fragrance. Well, beauty she was and is, and she has a lot of soulless sisters, but an equal number that more than make up for her deficiency. A number of years ago, the late James Gamble whose name lives on in the Royal National Rose Society with his cup awarded for fragrance, ran a test on well over three thousand Hybrid Teas. The conclusion was that 25% had either no fragrance or only a small amount, 20% were intensely fragrant, and the remainder fell somewhere in between. Sounds to me like the good old "bell curve" that explains a lot of natural occurrences.

As reported in earlier editions of the ARS Annual, a Mr. N.F.Miller attempted to establish a classification for rose fragrances on what he termed seven basic fragrances, namely ROSE, meaning old rose fragrance, NASTURTIUM, ORRIS (Iris root), APPLE, LEMON, VIOLET, and CLOVE. All cultivars, he claimed, had a fragrance that contained one or more of these in some proportion. Well, it was an interesting idea, but nothing seems to have come of it.

It is possible to trace more than a third of the world's known HT cultivars to the old rose 'Lady Mary Fitzwilliam.' Her progeny include such names as 'Mme Caroline Testout', 'Crimson Glory', 'Ena Harkness', and 'Josephine Bruce', all of which carried that wonderful Damask rose fragrance in their makeup. I have not attempted to trace the lineage since then, but I will wager they are fragrant! We should note, however, in conjunction with the seven basics listed above that most of these odd fragrances derive from 'Soleil d' Or', the scruffy looking yellow child of a Hybrid Perpetual and 'Rosa Foetida.' From that line, of course, came our bright yellows and oranges, our non-bluing reds, and that wonderful palette of fragrances like raspberry md other fruit flavors, and the spicy clove inspired aromas. (Not to mention Blackspot!)

Consider, also, that other members of the genus have contributed their own notes to the palette. The musk rose, 'Rosa Moschata' lends a pungent, by no means disagreeable touch. The coming of Teas and Chinas brought what some have called the real depth of fragrance to the modern rose. The Rugosas, those hardy, bug-proof beauties (alas, no form) have a strong, sweet fragrance, and our own native wild roses have made a contribution. Among the roses of China that have made a lasting home here is the ubiquitous rose of the deep South, the 'Lady Banksia' rose, which passes for violets. The fragrance of our beloved rose is said to be the only fragrance that never tires the human olfactory system. Other odorous materials quickly fatigue the system; indeed, some noxious vapors can become real life threats because the human sense of smell shuts down as a warning system when it gets too much. But the rose never fatigues the nose!

A humorous account was found in the 1968 ARS Annual which carried the story of an ARS convention featuring one of the most renowned figures of the rose world. During a Q & A period, some unfortunate woman asked, of the rose the speaker was touting, "What ODOR does that rose have?" whereupon the speaker, drawing himself up haughtily, nailed her to the wall with his reply, "Madame, roses have FRAGRANCE; garbage cans have ODORS!"

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Interestingly, the odor or roses (yes, "odor" is correct from a scientific sense... the speaker above is simply being a prissy, self-agrandizing fool) *is* not one which we habituate to in any great extent. The chemistry behind this ties into our evolution. One particular constituent of the rose odor is remarkably similar to a compound that is exuded by both men and women during arousal. Neither this component in humans, nor this component of the odor of roses is detectable as a specific identifable smell, for it is part of the human pheromonal system, but even lacking an identifable smell, it none-the-less stimulates and triggers receptors in our nasal cavity that send signals to our hypothalamus (a region of the brain) which in turn will send signals to our gonads and copulatory structures to stimulate them and make us (both men and women) feel aroused.

Therefore, gentlemen, if you would like to increase the odds that you and your special someone will want to engage in physical passion with each other, you may wish to send your special someone a bouquet of roses... especially tommorrow, February 14th. I have a dozen on order to be delivered to my lovely wife during the afternoon while I am still teaching at the University. They are a mixture of white, pink, and red.

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