A Gardener’s Pride and Joy

Although this article arrives rather late, I have had it in mind to write about my lilies of the valley since the beginning of May when they were in bloom. During that time, bunches of these white porcelain bells could also be found wrapped in their green leaves and sold as bouquets. But since I much prefer the process of growing and coaxing a plant into blooms, especially one whose fragrance I have yet to smell in situ, I had planted their rootstocks or ‘pips’ in autumn last year. They lay dormant over the winter and only began to send out their leaves in mid-March when the weather warmed. A littler later, some flower stalks emerged, and I could enjoy the redolence of spring.

muguet pips

Pips emerging from dormancy in spring. The carpet of seedlings around the pips are violets, which also emerge from the seeds of last year.

The perennial lily of the valley or muguet (Convallaria majalis) returns every year to perfume the spring air. But despite its delicate-looking white bells, muguet is highly poisonous and, especially without blooms, often dangerously mistaken for the edible herb bear leek (Allium ursinum). Nonetheless, grow a small patch in a dedicated pot of its own for an olfactory pleasure and all the caution can be thrown in the wind.

Its ethereal scent smells fresh, obviously floral, even spicy, and with a watery green tone. I would describe it as a mix of rose, clove, jasmine, green saps, and musky sweetness. But in spite of these contrastingly opulent notes, the overall character of muguet is reserved, and it feels like a subtle and an elegant way of announcing spring. Lily of the valley, as such, has been a prime objective of perfumers who have tried to capture its mesmerising scent and, along with it, the allure of spring.

Lily of The Valley in Perfumery

Just as elusive as it is captivating, lily of the valley virtually refuses to be extracted. Steam distillation does not yield a desirable quality of essential oil and solvent extraction with either petroleum ether or butane, though sufficient to produce the concrete for research, gives too low a yield to be commercially tenable. Perfumers must therefore rely on their memory and headspace analysis of the natural scent to reconstitute and interpret lily of the valley with existing essential oils and aroma ingredients.

The first of such aroma chemicals were the aldehydes (-CHO), such as hydroxycitronellal, Lilial, and Lyral. These are some of the most well-known muguet odorants of this family. Hydroxycitronellal was the prototype; it encompasses all the facets of lily of the valley — despite itself not being naturally occurring. It had been discovered and marketed by Knoll & Co. in 1905, but soon various qualities from other manufacturers were available, such as Laurine (1906) and Cyclosia (1908). The next stage of muguet was, then, dominated by Lilial and Lyral, starting from the 1960s. They would eventually come to supplant hydroxycitronellal.

These muguet aldehydes found their use directly in a composition or alternatively in a compounded base. Hydroxycitronellal, for instance, first found its fame with the aldehydic floral perfume Quelques Fleurs (Houbigant, 1912). It had also been used to compound Lily 7 — a base comprising seven ingredients — which was employed in the composition of Arpège (Lanvin, 1927), another successful aldehydic floral perfume. Other classic perfumes such as Chanel N°5 (1921), Ma Griffe (Carven, 1946), L’Air du Temps (Nina Ricci, 1948), and Youth Dew (Estée Lauder, 1952) likewise benefited from this lily of the valley odorant. But hydroxycitronellal was just as popular in the enduring fragrance of Nivea Cream, which has notes of muguet, ylang ylang, rose, geranium, violet (ionones) as well as cinnamic and balsamic ones.

Later perfumes, however, relied more on the newly available odorants when they were first created. For example, Fidji (Guy Laroche, 1966) employed Lyral, imparting thus a green tone to its floral bouquet. Similarly, Calandre (Paco Rabanne, 1969) used Lyral in addition to hydroxycitronellal to give a green emphasis that accentuates its character of metallic rose. Even more so, the elaborate floral accord of Anaïs Anaïs (Cacharel, 1978) was based on hydroxycitronellal, Lilial, Lyral, and Cyclamen aldehyde. Interestingly, compositions such as Aromatics Elixir (Clinique, 1971), Coriandre (Jean Couturier, 1973), and Paloma Picasso (1984) used a combination of the muguet aldehydes partly for their floral notes that contrast beautifully with patchouli.

Interestingly, such muguet aldehydes was also used in the formation of Schiff bases. When an amine (-NH2) reacts with an aldehyde (-CHO), a Schiff base and water are formed. For example, methyl anthranilate reacts with hydroxycitronellal and Lyral to form Aurantiol and Lyrantiol, respectively. The Schiff bases produced can give odours of orange blossom, linden blossom, or tuberose. Perfumes such as Oscar (Oscar de la Renta, 1977), Poison (Dior, 1985), and Lou Lou (Cacharel, 1987) derived much of their sweet floral character in such a manner at the time.

Even in the last few years, the classic muguet aldehydes, such as hydroxycitronellal, Lilial, and Lyral could still be found. In adr_ett (Nomenclature, 2015), the lily of the valley, which lends a green floral touch to the fruity musk, was based on the combination of hydroxycitronellal and Lilial. And, as much as 12% Lyral was used in Inflorescence (Byredo, 2013) to build its lily of the valley character. Indeed, these muguet aldehydes have proved to be one of the enduring ingredients of perfumery.

But that is about to change.

Due to their skin-sensitising potential, these muguet aldehydes are facing restrictions. Hydroxycitronellal is allowed only up to certain concentrations depending on the end use, but Lilial and Lyral are severely restricted. According to the Scientific Committee on Consumer Safety (SCCS), Lilial is considered ‘not safe for use as fragrance ingredient in cosmetic leave-on and rise-off type products’ even at the concentrations set by the International Fragrance Association (IFRA), and Lyral ‘should not be used in consumer products’.

New odorants are therefore being developed to replace these restricted ones. Amongst them, the aldehydes  account for a broad range of muguet odour profiles that includes names like Dupical, Florhydral, Melafleur, Floral Super, Cyclemax, et cetera. There are also the alcohols (-OH), such as Mayol/Meijiff, Florol/Florosa, Mugetanol, Majantol, Lilyflore, Muguesia, and Super Muguet, and these are a sought-after class of muguet odorants because of their non-sensitising nature. Super Muguet, for instance, was first used in contrasting the fig accord of Marc Jacobs Men (2002), and it was later used in the oriental-gourmand Noir Pour Femme (Tom Ford, 2015). Amongst recently debuted ingredients, I had the chance to smell Mahonial, which offers a diffusive, creamy lily of the valley note reminiscent of the yellow blooms of Mahonia japonica, from whose name it is derived. Mahonial was first employed in the floral heart of Missoni (2015), and now one can smell its transparent yet creamy note in L’Homme (Prada, 2016) and La Femme (Prada, 2016), both containing Mahonial at approximately 4% and 2%, respectively.

As reflected in the many examples of perfumes, the muguet note is a part and parcel of many different styles of fragrances. It follows then that the quest for safe, stable, and impactful lily of the valley aroma chemicals must continue.

Lily of The Valley in Perfumes

The fresh watery appeal and creamy sensuality of muguet lend a special touch to a composition. For this reason, it is not limited to soliflore perfumes, and forms an important part in many styles of compositions.

But, of course, if one wishes to know how perfumers interpret lily of the valley, exploring soliflore perfumes is a good option. There have been several other muguet soliflores since the eighteenth century, from Lily of The Valley (Floris, 1750), Premier Mai (Houbigant, 1908), Muguet de Chaville (Cheramy, 1910), Muguet des Bois (Coty, 1941), Muguet du Bonheur (Caron, 1952), and Muguet de Guerlain (1998 by Jean-Paul Guerlain), to name a few. But I would rather offer a few favourite choices of this flower.

Naturally, one of these is the most well-known and appreciated lily of the valley: Diorissimo (1956). Considered to be the gold standard, its fresh green floral and surreptitious animalic notes conjure the vernal impression of damp woodlands covered in infinite patches of lily of the valley. In the current eau de toilette, its muguet has lost some radiance and its woodlands short on their animalic richness, but I think that its curious paradox of an ethereal flower with a veiled depth still rings true.

However, the lily of the valley that I find most captivating is far from the time-tested repertoire of classics. Muguet Porcelaine (Hermès, 2016), I feel, takes after the spirit of Diorissimo in simplicity and subtle depths, but its singular focus is where it diverges. Whereas Diorissimo is an impressionistic rendering of blooms in their woodlands, Muguet Porcelaine is a careful treatise dedicated solely to muguet, examining its accents and shades. Led by fresh accents of rose and clove, its green floral is not only depicted in detail, but also underpinned by watery melon and green sap that remain fresh until the dry down.

Other than the soliflores, the lily of the valley note, as evident in the examples heretofore, finds itself in various genres. Indispensable to the bouquet of the aldehydic florals, lily of the valley is a part of perfumes such as Chanel N°5, Arpège, Madame Rochas (1960), Calandre, Rive Gauche (Yves Saint Laurent, 1971), and White Linen (Estée Lauder, 1978). It is also found in the multiplex bouquets of L’Air du Temps, Fidji, and Anaïs Anaïs. Beyond these floral bouquets, it finds contrast and harmony in many interesting accords. In perfumes such as Aromatics Elixir, Coriandre, and Paloma Picasso, the lily of the valley accentuates the floral complex that is set against the patchouli and woods. This contrast between muguet and patchouli is also employed in the mellis accord of oriental perfumes such as Opium (Yves Saint Laurent, 1971) and Coco (Chanel, 1984). But the lily of the valley also shines brightly with green notes, where its green floral character finds harmony. In Chamade (Guerlain, 1969), a hint of muguet bridges between the green galbanum and hyacinth opening and the floral heart. This bridge between green galbanum and floral heart is similarly found in Chanel N°19 (1970). As the green notes are making a come-back, so too is the lily of the valley note, and this is seen in the green, dewy floral introduction of Miu Miu (2015).

But ultimately the perfume that has a special place in my memory of May is that of the lilies of the valley which I had coaxed into bloom. They were my pride and joy.

Sources: M. Meunier, Ind. Perfum., 5, 26, 1950; Naves and Mazuyer, Les Parfums Naturels, Paris (1939), p 250; Scent and Chemistry The Molecular World of Odors p 13, 108; SCCS Opinion on HICC SCCP/1456/11 revised 27 July 2012; SCCS Opinion on BMHCA SCCS/1540/14 revised 16 March 2016.

*Lilial is a tradename for butylphenyl methylproprional (BMHCA).

*Lyral is a tradename for hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC).

An Infusion of Jasmine and Climbing Ylang Ylang

Our garden always mesmerises me with an array of flowers and herbs. One of the most familiar smells is the narcotic sweet scent of jasmine sambac (Jasminum sambac) at dusk. But as the evening breeze blows, it brings also the fruity, ylang-ylang-like aroma of karawek or climbing ylang ylang (Artabotrys siamensis)* from the neighbour’s. These two fragrant floras have long been used in Thai perfumery and cuisine. My mother, as I recall, would extract their essences for the traditional desserts. So, when I chanced upon these blooms, I felt inspired to share a simple infusion that she would often make.

The recipe is fairly straightforward, but there are some tricks to getting it right. Knowing when to pick requires careful observation. The flowers should be collected when they are most fragrant, which is at dusk. The jasmine sambacs can be picked even when they have not opened; these unopened flowers will eventually bloom and release their scent overnight. But only the ripe yellow karaweks, which are fragrant, should be picked. And each of the six petals should be separated from the calyx.

The flowers are quickly rinsed before being gently placed in a bowl of water. The water is allowed to absorb the scents overnight. Care should be taken not to cause disturbance because the flowers would otherwise become ‘bruised’ and the infusion would acquire a sharp vegetal note of crushed leaves. The spent flowers are removed and the process is repeated once more with a new set of flowers to saturate the infusion with their perfume.

One can use this infusion for a number of purposes. My mother often uses it to make a syrup, and the aroma still lingers on even after the infusion is boiled with sugar. One can also include other fragrant flowers for a complete water-based eau de cologne. I, on the other hand, simply use it to spike a glass of chilled water. It makes for a refreshing beverage with a pleasant lingering after-taste. But be warned: it is potent, and a tablespoon suffices to perfume a whole jug of water.

A note on classification*: The family Annonaceae includes the classical ylang ylang (Cananga odorata) used in perfumery and other plants with similarly strongly fragrant flowers. Karawek (Artabotrys siamensis) belongs to the Artabotrys genus of this family, which explains why it shares some olfactory characteristics with ylang ylang.

Gardenia

The weather warms, so my gardenia buds open, seeking attention and permeating the night air with their perfume. As I made a study of the fragrance, I decided to write on this nature’s wonder. The common gardenia (Gardenia jasminoides) has highly fragrant white flowers. In the evening, the opening buds smell slightly green and piquant because of the salicylate aspect. The flowers also smell creamy, recalling coconut and peach skin. There is an unmistakably heady indolic element of jasmine. In ripe blooms, they have a sharp green ‘mushroom’ overtones. Gardenias also share some aspects with lily, lily of the valley, ylang ylang, and a bit of rose.

In terms of composition, (E)-ocimene, linalool, methyl benzoate and a number of tiglates compose the gardenia flower headspace. However, there are likely olfactory variations amongst species. For example, the critically endangered native of Hawaii Gardenia brighamii, as demonstrated by headspace analysis of its gas-phase components, contains 41% methyl benzoate, 13% (3Z)-hex-3-enyl benzoate, 7% indole that recalls ‘white-flower smell’, 7% jasmine lactone that lends the jasminic and coconut touch, and 3.7% (3Z)-hex-3-enyl tiglate that gives the tang of soil fungi and mushrooms to the flower. It is possible to extract the desired fragrance from their flowers by enfleurage as the villagers of Fusagasugà in Colombia have continued to produce gardenia absolute since 1945. However, such enfleurage-derived absolutes are rarely ever produced in industrial scale due to the exorbitant costs involved. And, yet, I have stumbled upon a solvent-extracted absolute of the Tahitian gardenia or Tiaré (Gardenia tahitensis) which can be used in fine fragrances up to 1% of a composition to impart the exotic white-floral quality.

Gardenia in Perfumery

Like many flowers that do not yield the desired quality of their scents or do so at a prohibitive cost of extraction, the smell of gardenia is also the object of fascination in perfumery. Early reconstitutions of gardenia often revolve around a tuberose note and aldehyde C-18 and may eschew styrallyl acetate altogether. Still, most gardenia bases almost always call for it. Such bases rely on its powerful rhubarb-like green note in combination with jasmine, rose, lily of the valley, lilac, and a small amount of orange blossom to render gardenia odour characteristics. But styrallyl acetate is rather harsh, so salicylates may be used to soften it along with aldehyde C-14 and C-18 as modifiers. The top note of such bases may call for aldehyde C-8 to C-12 and citrus oils such as lemon, mandarin, orange, or bergamot. To fix the components, heliotropin, coumarin, musk, labdanum, myrrh, tolu balsam, cinnamic alcohol, and synthetic ambergris may be used.  Other aroma chemicals such as the mildly floral ‘gardenia oxide’ (isoamyl benzyl ether) and the citrusy fruity linalyl isovalearate are sometimes incorporated into gardenia compounds. Meanwhile, perfumer Jean-Claude Ellena, who professes his love of simplicity, draws a more-or-less complete gardenia note with just three ingredients: the fruity sweetness and coconut of aldehyde C-18 (γ-nonalactone), the fresh green of styrallyl acetate (Gardenol), and the Concord-grape sweetness of methyl anthranilate. Indeed, the reconstitution of gardenia is subject to the creative interpretation of the perfumer.

Gardenia in Perfumes

In fine fragrances, gardenia was initially a secondary floral. It formed part of the composition, but was itself not featured. For instance, gardenia found its way into the floral aldehydic L’Aimant (Coty, 1927) via the styrallyl acetate contained in infusions of jasmine, cassie, and tuberose used in the original formula. The green freshness of gardenia pairs well with chypre accords in perfumes such as Bandit (Robert Piguet, 1944), Ma Griffe (Carven, 1947), Miss Dior (1947), Cabochard (Grès, 1959), Coriandre (Jean Couturier, 1973), Michelle (Balenciaga, 1979), and the excellent fruity chypre La Panthère (Cartier, 2014).

Gardenia as main floral theme can be seen starting from soliflores like Gardénia (Chanel, 1925) and Jungle Gardenia (Tuvaché, 1933). If you like your gardenia creamy, Lou Lou (Cacharel, 1987) offers an interesting interpretation of the creamy Tahitian gardenia or Tiaré based on an oriental accord and tuberose. Another very creamy, coconut-like gardenia is Crystal Noir (Versace, 2004). But if you like the company of magnolia and jasmine, the bright gardenia of Un Matin d’Orage (Annick Goutal, 2009) may suit you better. A recent resurgence of the note seems to have produced a slew of gardenias for everyone, ranging from the sombre gardenia of Une Voix Noire (Serge Lutens, 2012), the fruity frangipani and gardenia of Gorgeous Gardenia (Gucci, Flora, 2012), to a full-fledged gardenia offered in the masculine context of Boutonnière No.7 (Arquiste, 2012). But for those who crave a more realistic impression, Gardénia (Robert Piguet, 2014) offers a no-frills flower with minimal contrasts.

mom gardenia

As for me, I cannot quite pick a favourite gardenia perfume at the moment. My pot of gardenia has had all the attention from me — perhaps, the only other rivals are the gardenias in my mother’s garden.

Sources: enfleurage.com, firmenich.com, P&F Vol.8 October/November 1983 by Danute Pajaujis Anonis, Perfumery: Practice and Principles; Scent and Chemistry The Molecular World of Odors, Scents of the Vanishing Flora

  1. Müller PM, Lamparsky D. Perfumes: Art, Science & Technology. Amsterdam, New York: Elsevier, 1991
  2. Tamogami S et al. Analysis of enantiomeric ratios of aroma components in several flowers using a Chiramix column. Flavour Fragr J 2004;19:1-5.

Part 3: Neroli oil and orange blossom absolute

This is the third and final part of the series ‘The bitter orange tree: bigarade, petitgrain, orange leaf, neroli, and orange blossom’.

If rose is the queen and jasmine the king, then bitter orange flower is the princess of all flowers. The youthful, radiant, and romantic scent of these vernal blossoms captures the spring time. The main extracts of bitter orange (Citrus aurantium subspecies amara) flower are neroli oil and orange blossom absolute.

orange blossoms.jpg

Legend has it that neroli oil is named after the princess of Nerola, Marie-Anne de la Trémoille, who was known to have perfumed her gloves and bath with the essential oil of bitter orange flowers. Neroli oil has a fresh floral profile with green and spicy tone that recalls petitgrain oil. But despite their olfactory resemblance, the contents of ocimenes, β-pinene, limonene, linalool, and linalyl acetate of neroli oil are higher than those of petitgrain oil. Moreover, neroli oil also possesses the jasmine odorant cis-jasmone as well as the exotic jasmine note of 1H-indole and the Concord grape of methyl N-methylanthranilate that differentiate it from petitgrain oil. And interestingly, despite coming from a citrus plant, nootkatone and other typical components of citrus oils are not found in neroli oil.

Production of neroli oil and orange blossom absolute concentrates in Tunisia, Morocco, and Egypt in April. It starts from manual picking. The flowers are picked by hand to avoid damaging the immature flower buds, which will be collected in subsequent harvests. After distillation, around 850 kg to 1000 kg of flowers yields 1 kg of neroli oil. The Tunisian oil has the fresh floral note of orange flower and is reminiscent of freshly ironed linen. The Moroccan variety possesses the fresh floral sweetness of orange flower, but also harbours green and animalic aspects.

To obtain orange blossom absolute, around 1000 kg of flowers are loaded into an extractor with a solvent for heating. The solvent is later removed by evaporation, leaving the liquid ‘concrete’ of orange blossom, which solidifies at room temperature due to the presence of wax in the flowers. The collected concrete is melted down and mixed with alcohol at 60°C. After an hour of mixing, it is cooled down to 0°C to remove the solidified wax from the mixture. Finally, the alcohol is removed by evaporation to yield roughly 1 kg of orange blossom absolute. Tunisian orange blossom absolute is floral, warm, sensual, and heady — typical of orange flower. The Moroccan origin is also warm, but more animalic and indolic. Moreover, the by-product of steam-distilled flowers can be solvent-extracted to produce orange blossom water absolute, which has a harsher orange blossom character, is less indolic, and not as heady when compared to the absolute.

There are several aspects that impart distinguishing features to neroli oil and orange blossom absolute. The hydrocarbons such as α-pinene, β-pinene, myrcene, limonene, and ocimene confer the bright citrus note. Particularly important are the ocimenes, which provide a very fresh citrus note with a subtle green accent. These compounds make up about 40% of neroli oil whose sparkling and diffusive character is used to add freshness to a composition. In contrast, the hydrocarbons constitute only around 6% in the absolute that is, nonetheless, employed to boost the floralcy of other components.

Meanwhile, the alcohols are a class that contributes to the floral notes. These include linalool, phenyl ethyl alcohol, α-terpineol, citronellol, nerol, geraniol, nerolidol, and farnesol. Amongst these, linalool provides much of the character impact.

As for the esters found in extracts of bitter orange flower, they serve as accents to modify the citrus notes. Such esters are linalyl acetate, methyl anthranilate, neryl acetate, citronellyl acetate, and geranyl acetate. Methyl anthranilate, also a nitrogenous compound, is the most important of its kind and can be found up to 10% in the absolute; its fruity and floral character is essential to both neroli oil and orange blossom absolute.

Yet, another minor but important class of compounds is phenol. Eugenol is an important phenol in extracts of bitter orange flower. Despite being a minor constituent, its spicy clove note imparts a kind of brightness and natural character to the flower.

Interestingly, important nitrogenous compounds found in extracts of bitter orange flower are the aforementioned methyl anthranilate, indole which is a potent floral chemical with animalic character, and pyrazines that impart green, dry, and earthy character. The high-impact 2-isobutyl-3-methoxypyrazine, for example, confers a green facet that recalls galbanum oil and green peppers to neroli oil. The pyrazines are, perhaps, what give orange blossom extracts their peculiarity that can add a long-lasting, signature freshness to the top note.

Neroli and Orange Blossom in Perfumery

Such insights into the chemical compositions of bitter orange flower are also essential to the reconstitution of an orange blossom or neroli note. This is because extracts from bitter orange flower are very expensive and, in most cases, can only be afforded in small amounts.

A classic reconstitution of the orange blossom note, for instance, is through a Schiff base formed by a reaction between an aldehyde (–CHO) and an amine (–NH2) such as methyl anthranilate. One of the most widely used Schiff bases in the reproduction of orange blossom and neroli notes is Aurantiol, which is produced by the reaction between hydroxycitronellal and methyl anthranilate. The only problem with Schiff bases is that they are strongly yellow and would pose a problem, should discolouration be a concern. In any case, they can be further used in compounding orange blossom or neroli notes in bases or fragrance composition itself.

New odorants for orange blossom or neroli notes have also been developed and could lend special signature to such fragrance bases, and hence fragrance compositions. Nerolione® is an example of a high-impact, very stable, non-discolouring orange blossom material. Even in small amounts, it performs excellently in challenging bases of household and personal care products. But it can also be used in fine fragrances to brilliant effects. Perfumer Maurice Roucel dosed a few parts of Nerolione in Insolence (Guerlain, 2006) and brought out the floral radiance of violet. It may not provide a scent of its own in a formula, but it creates a synergy with floral and fruity notes, giving a blooming effect.

Neroli and Orange Blossom in Perfumes

In terms of use, neroli oil most famously finds itself in eaux de cologne. In the past, we would find around 7% neroli oil in 4711 Echt Kölnisch Wasser (Mülhens, 1792) or even 5% neroli oil in the revived Green Water (Jacques Fath, 2015) in contrast to the 0.5% neroli oil that lends just a bright dandy touch in Habit Rouge (Guerlain, 1965). An example of a ground-breaking composition in the eau de cologne style that employs neroli is Eau Sauvage (Dior, 1966).

Moreover, we also find orange flowers in compositions of other styles such as lavender water, aldehydic, chypre, and amber types. These include Chanel N°5 (1921), Arpège (Lanvin, 1927), Fleurs de Tabac (Cherigan, 1929), Vol de Nuit (Guerlain, 1933), Fleurs de Rocaille (Caron, 1934), Miss Dior (1947), English Leather (1949), and Fidji (Guy Laroche, 1966). Another interesting example is the development of a jasminic facet of neroli oil in 24 Faubourg (Hermès, 1995). The sensual floral character of orange blossom is key to masterpieces such as Après L’Ondée (Guerlain, 1906) and L’Heure Bleue (Guerlain, 1912).

Sources: P&F Vol.6 June/July 1981 by Felix Buccellato, P&F Vol.16 November/December 1991 by Mans H Boelens and Antonio Oporto, P&F Vol.9 February/March 1995 by Danute Pajaujis Anonis, P&F Vol.34 March 2009 by Jeb Gleason-Allured, Scent and Chemistry The Molecular World of Odors, west-crete.com

Part 2: Petitgrain oil and orange leaf absolute

This is the second part in the series of ‘The bitter orange tree: bigarade, petitgrain, orange leaf, neroli, and orange blossom’.

biolandes petitgrain moroco

The main extracts from bitter orange leaves are petitgrain oil and orange leaf absolute.

Petitgrain oil is produced by steam distillation of leaves and twigs of the bitter orange tree (Citrus aurantium subspecies amara). The video below shows a traditional petitgrain oil production in Paraguay. Traditionally, the branches are harvested manually with machetes and transferred to the on-site distillery. The wood still is filled with the harvested leaves and branches before it is covered with a lid and sealed with wet clay. The resulting petitgrain oil is immiscible and forms a layer on top of water. Usually, 500 to 600 kg of leaves and twigs yield 1 kg of petitgrain oil.

The oil is intensely bittersweet, woody, fresh floral, and with a green undertone. It is mainly produced in Paraguay from October to March, but a higher-grade oil comes in small quantities from France, Southern Italy, Morocco, and Tunisia in June and July. Petitgrain oil from Paraguay has a characteristic bitter green note with a slight floral touch of neroli oil. Tunisian variety possesses also a bitter green note, but is the most floral amongst the origins of petitgrain oil.

Sometimes, the leaves are solvent-extracted, and around 500 kg of leaves yield 1 kg of orange leaf absolute. It has a powerful bitter green note, but is a step down from petitgrain oil; its dry down is soft and with a marine facet. Interestingly, even the water by-product from the steam distillation of the leaves and twigs can be further solvent-extracted. It takes up to 3300 kg of leaves and twigs to produce just 1 kg of orange leaf water absolute that has a deep bitter green note precisely recalling plucked leaves. It is also slightly smoky and long-lasting. In any case, I imagine these two types of absolute to be incredibly expensive!

In terms of composition, petitgrain oil can comprise up to 80% of the 2:1 mixture of linalyl acetate and linalool. There are also geranyl acetate, neryl acetate, and α-terpinyl acetate that are important. Petitgrain oil also contains geraniol, nerol, α-terpineol, nerolidol, as well as the woody spathulenol and isospathulenol — both of which are constituents of clary sage oil. Interestingly, small amounts of high-impact compounds like the violet-smelling β-ionone and rose-smelling β-damascenone can be found in petitgrain oil. Certain aldehydes, present in minor quantities, also contribute to the character of petitgrain oil. Some aldehydes impart strong, exotic, spicy odours. 3-ethyl-benzaldehyde, on the other hand, possesses a benzaldehyde-like odour with a mimosa undertone. Yet, another aldehyde confers a fresh peel note. There is also a galbanum-reminiscent green note of 2-isopropyl-3-methoxypyrazine. And though extracted from a citrus plant, nootkatone and other typical components of citrus oils are not found in petitgrain oil. Such is the complexity of a deceptively simple perfumery material that is petitgrain oil.

Petitgrain in Perfumes

As with many citrus ingredients, petitgrain oil is classically related to the eau de cologne genre. For example, Original Eau de Cologne (Farina, 1709) by Johann Maria Farina contains 20% petitgrain oil. The classic 4711 Echt Kölnisch Wasser (Mülhens, 1792) by Wilhelm Mülhens features 11.3% petitgrain oil. However, petitgrain oil can also provide natural brightness to the aldehydic floral genre, and the iconic Chanel N°5 (1921) in the original formula is one such prime example that contains 1% petitgrain oil. Moreover, petitgrain oil is used to brighten oriental or floral compositions, but it is rarely dosed more than 2% in modern times. Such a relatively high dose of 2% is found in Habit Rouge (Guerlain, 1965), Eau Sauvage (Dior, 1966), and Eau d’Hadrien (Annick Goutal, 1993).

Beyond these, petitgrain oil is also used as a substitute for the more expensive neroli oil in functional products. This is because of its relatively inexpensive price and good performance even in bases such as air fresheners and soaps. Still, the high content of linalyl acetate makes petitgrain oil unstable in strong detergent.

Part 3: Neroli oil and orange blossom absolute

Sources: biolandes.com, Scent and Chemistry The Molecular World of Odors

  1. Zarzo M.Sensors (Basel, Switzerland). What is a Fresh Scent in Perfumery? Perceptual Freshness is Correlated with Substantivity. 2013;13(1):463-483.

Part 1: Bigarade or bitter orange oil

This is the first part in the series of ‘The bitter orange tree: bigarade, petitgrain, orange leaf, neroli, and orange blossom’.

Citrus aurantium fruit

Seville, Spain, is famous for its abundance of bitter orange trees (Citrus aurantium subspecies amara) that line the streets. Their prolific blossoms perfume the air in spring. They were brought in the ninth century by the Moors that ruled the south of Spain. The local bitter orange fruits are not directly consumed due to its intense sourness and bitterness, but are prized for their high pectin content — perfect for making marmalade.

The peel is, however, valued for its fragrant essential oils extracted by cold pressing. Bigarade oil is sourced from various places, but especially from Argentina and Ivory Coast. Despite being strongly citrusy, it is remarkably different from sweet orange oil (Citrus sinensis). Bigarade oil is less aldehydic, and possesses a fresh floral and bergamot-like character. Its pronounced bitterness is due to the presence of non-volatile, polar components that also set it apart from sweet orange oil. Certain molecularly distilled quality of bigarade oil provides a more intense fruity, zesty orange note with a balance between aldehydic character and fruity sweetness. Some main constituents are aliphatic aldehydes, oxygen-containing mono- and sesquiterpenes. Aldehyde C-8 to C-14, linalool, linalyl acetate, nootkatone, and α-selinenone could contribute to its odour character.

parfumo

In perfumes, bigarade oil imparts distinct freshness to the composition, and for instance, is featured in Cologne Bigarade (Frédéric Malle, 2001) with as much as 50% bitter orange oil.

Part 2: Petitgrain oil and orange leaf absolute.

Sources: andalucia.com, Scent and Chemistry, The Molecular World of Odors, parfumo.de

  1. Ling Zhengkui, Hua Yingfang, and Gu Yuhong, The Chemical Constituents Of the Essential Oil from the Flowers, Leaves and Peels of Citrus Aurantium; in: Proc of the Intl Conf on Ess Oils, Flavours, Fragrances and Cosmetics, 380-381, Beijing, China, 9-13 October (1988).
  2. Mans H Boelens, Critical Review on the Chemical Composition of Citrus Oils, Perf & Flav, 16(2), 17-34 (1991).
  3. Mans H Boelens and Rafael Jimenez Sindreu, Essential Oils from Seville Sitter Orange (Citrus aurantium L. ssp. amara L.), BM Lawrence, BD Mookherjee and BJ Wllis (Editors), Flavors and Fragrances: A World Perspective. Proc of the 10th Intl Congr of Ess CMs, Fragrances and Flavors, Washington, DC, Elsevier Sci Publ BV, Amsterdam (1988).
  4. Mans H Boelens and Rafael Jimenez, The Chemical Composition of the Peel Oils from Unripe and Ripe Fruits of Bitter Orange, Citrus aurantium L ssp amara Engl, Flavour Fragr J, 4, 139-142 (1989).

The Bitter Orange Tree

seville orange

Amongst the most useful citruses in perfumery is the bitter orange tree (Citrus aurantium subspecies amara). The plant can be extracted for different ingredients. The cold-pressed fruit peel produces bitter orange or bigarade oil. The steam-distilled leaves and small branches yield petitgrain oil, whereas their solvent-extraction produces orange leaf absolute. As for the flowers, they can be steam-distilled to produce neroli oil or extracted by solvent to produce orange blossom absolute.

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Of course, the flowers and leaves of other citruses can be similarly extracted. For example, the sweet orange tree (Citrus sinensis), whose fruit peel is cold-pressed to give sweet orange oil, can yield neroli oil by steam distillation or orange blossom absolute by solvent extraction — albeit of inferior qualities.

It is the bitter orange tree that contributes significantly to the typically used orange blossom absolute and neroli oil. Despite coming from the same plant, the composition of bigarade oil, petitgrain oil, orange leaf absolute, orange blossom absolute, and neroli oil each differs markedly. I will discuss each of these ingredients in the upcoming posts.

Part 1: Bigarade or bitter orange oil

Source: happen-upon.com