Tinh dầu Comoros và Réunion: ngọc lan tây, phong lữ Bourbon, vetiver Bourbon

Ylang ylang (Cananga odorata, form genuina) has been grown in the Comoros since the late 19th century; in 1885 Léon Humblot obtained a concession on Grande Comore and set up plantations for spices and perfume plants. From the 1960s and 1970s, as estate land was redistributed, Comorian farmers began distilling on their own.

According to Pierre William Johnson's value chain study (2023), the Comoros produce 40 to 70 tonnes of oil a year, out of roughly 100 tonnes worldwide. Anjouan accounts for about 70% of the Union's output. In the early 2010s Anjouan had some 300 distillers; in 2022 between 100 and 150 were active. Mohéli has 60 to 90 distillers, a sharp expansion since the price peak of 2017 to 2018. Grande Comore has only a handful of stills.

Flowers are picked by hand in the morning and distilled the same day. Each tree gives about 1 kg of flowers per picking round; a still takes 100 to 200 kg. On Anjouan some 5,000 to 6,000 women work as pickers.

Ylang ylang is one of the few essential oils sold as fractions of a single distillation. The first oil to come over, rich in the lightest and most fragrant molecules, is called Extra (sometimes split further as Extra S or Extra Superior). Grades I, II and III follow, each heavier and richer in sesquiterpenes. "Complete" oil is the whole run without cuts, or a blend of fractions.

ISO 3063 separates the grades mainly by density. At 20 °C, Extra S is 0.980 or above, Extra about 0.965 to 0.975, grade I about 0.960, grade II about 0.955, grade III the lowest.

Extra is high in strong smelling molecules: p cresyl methyl ether 5 to 16%, methyl benzoate 4 to 9%, linalool 7 to 24%, benzyl acetate 5.5 to 17.5%, geranyl acetate 2.5 to 14%. Later grades are richer in germacrene D, beta caryophyllene and alpha farnesene. A comparison of Comorian and Malagasy oils found more cinnamyl acetate, benzyl salicylate and farnesyl acetate in the Comorian oils.

Ylang ylang contains several EU labelled allergens, including linalool, geraniol, benzyl benzoate and benzyl salicylate.

With little electricity, most Comorian stills burn wood. Traditional stills reach only 15 to 25% energy efficiency; improved designs from 2015 to 2017 reach 50 to 55%. Ylang distilling uses some 12 to 15% of the country's fuelwood. Anjouan has lost about 70% of its native forest, and its permanent streams have fallen from about 40 to 7.

Prices move in cycles. After the 2017 to 2018 boom, large stocks and COVID 19 pushed prices sharply down from 2019 to 2022, cutting distillers' and pickers' incomes several fold. Adulteration and fraud, such as adding synthetic benzyl acetate, have been reported for about 15 years. In 2020 the Comoros set up a national interprofessional body; since March 2022 distillers and collectors must register.

Mayotte fell from 18 to 30 tonnes of oil in the late 1990s to 1 or 2 tonnes a year after becoming a French department (2009 referendum), as labour costs rose. In Madagascar, Nosy Be and the Ambanja area exported 91 tonnes of oil in 2019 and 77 tonnes in 2021; in 2026 the Malagasy press reported prices down to a third and many stills closed.

Rose scented geranium (Pelargonium, a hybrid group close to P. graveolens and P. capitatum, known in French as géranium rosat) reached Réunion around 1870. It is grown in the western uplands above 800 m, mainly on the slopes of Maïdo, and distilled in small stills on the farm.

Oil output reached 173 tonnes in 1929, 155 tonnes in 1939 and 165 tonnes in 1965. The decline since has been steady: 25.3 tonnes in 1991, 4.1 tonnes in 1996, about 2 tonnes in 2015. In 2015 about 150 hectares and 140 growers remained; 65% of them delivered less than 10 kg of oil a year. The CAHEB cooperative in Le Tampon, founded in 1963, is the only collector. By 2015 China had become the largest producer of geranium oil; Egypt is another major source.

Bourbon type geranium oil is rich in citronellol and geraniol, carries isomenthone, and is told apart from Egyptian oil by guaia 6,9 diene (present in Bourbon oil) and 10 epi gamma eudesmol (typical of Egyptian oil). Much oil sold as "geranium Bourbon" actually comes from Madagascar or elsewhere, grown from the same clones; the name describes an oil type and does not guarantee Réunion origin.

Réunion was also once an important source of vetiver, valued for its quality. The trade declined because Haitian oil cost far less and labour on the island grew expensive. Vetiver now survives mainly in the southern uplands of Saint Joseph, in very small volumes for the local market and artisan perfumers. The oil is still collected through CAHEB.