In this second installment of Chemistry Flash series I would like to introduce you to chemical compound known as coumarin. It’s an organic molecule of C9H6O2 formulae and belongs to the class of benzopyrone. In its pure state it forms colorless crystals that melt at 71°C. It’s density is slightly lower comparing to water (0.935 g/cm3). It’s popular to many plants. By the way, it’s insoluble in water.
Coumarin can be found in highest amounts in tonka beans – the substance takes its name from French word coumarou, which means tonka bean. In smaller amounts it’s present in vanilla grass, sweet woodruf, sweet grass, mullein and cassia cinnamon.
This aroma chemical has a sweet smell which is often compared to the smell of new-mown hay. Believe it or not but coumarin is present in perfumery since 1882. First perfume that contained coumarin in its composition was Fougère Royale from the perfume house of Houbigant. It originally contained a whopping amount of 10% of coumarin in finished creation. Use of coumarin in perfume gave birth to new olfactory family known as fougère.
Synthetic coumarin obtained in laboratories with many sophisticated methods can posess a tobacco-like aroma but it can also evoke caramely undertones. Diluted in perfumer’s alcohol it can project in a hazelnut, powdery almond way. Isn’t it surprising how just one perfume ingredient can be perceived in so many different ways? Sometimes coumarin works as an addition to pipe tobaccos and some alcoholic drinks to enhance their aroma. I never had a chance to smell pure coumarin essence or its diluted form, I asked my professor if we had it in our university labs, but we don’t.
According to IFRA (Internation Fragrance Association) files coumarin is a restricted ingredient. I don’t know exactly how those restrictions are working but if we classify perfume as deodorants/antiperspirants the amount of coumarin can’t exceed 0,13%, in case of treating perfume as hydroalcoholics for shaved skin the amount rises to 0,5%.
Some perfume feauturing coumarin (noticeable or not) are:
- Guerlain Jicky, Samsara, Tonka Imperiale
- Chanel Coco, Bois des Iles
- Annick Goutal Nuit Etoilee
- Perris Monte Carlo line-up (will be reviewed soon)