Tonka bean is the name given to the seeds of a tree known as the Dypterix Odorata, which is a species of flowering tree of the pea family. This tree is original from Central America and Northern South America.
The seeds can be easily recognizable for their unique qualities: they are black and wrinkled and have a smooth dark interior. Despite its suggestive name, it is not the true what has a unique odor, but the seeds. These seeds have strong fragrance –similar to sweet woodruff- that has made them well-known to the rest of the world.
The seeds have also gained notoriety for its toxicity. Despite being widely sought-after for their fragrance, Tonka Beans have been found to be harmful to the human body. Actually, the substance responsible of producing both the odor and the toxicity is called Coumarin, which is a chemical isolate of the plant. Each seed has been found to contain from 1% to 3% of this chemical with a maximum dose of 10% on rare occasions.
As a food additive, this substance’s use has been closely controlled because of its toxicity –research has shown that it can cause hemorrhage and liver damage in humans. However, when it comes to the perfume industry, its contribution is essential because it is thanks to this substance that the Tonka Bean contains any fragrance, at all.
History, Growth and Cultivation
The Dypterix Odorata is a large-growing tree which produces large purple flowers, each of which produces one single bean. Grown in tropical areas, such as Central or South America, this tree became known in Europe in the late 18th century. Its use soon became widespread, mainly because of its aromatic properties. Slightly resembling the taste and aroma of saffron, cinnamon and cloves, it became an exotic substitute for the vanilla bean and began to be used to scent soap and tobacco, among other uses. These days however, synthetic extract is what is being used over the natural one.
Tonka Bean and its Uses in Perfumery
The Tonka Bean absolute is produced by soaking the beans in rum and letting them sit there for about 12 to 24 hours. After this process has taken place, the beans are dried in order to allow the white crystals of the Coumarin come to the surface.
It is these powdery white crystals the elements that are responsible for intensifying the aroma during the extraction process. The absolute –described as balsamic, vanilla-like and oily- which is generated from this extraction is a powerful odorizing ingredient used later on to make essential oils and perfumes.
As for categorization, the Tonka Bean corresponds to the oriental category of perfumery notes and shares similar qualities such as the ones found in amber or tobacco. Consequently, when it comes to combining this fragrance with other substances, careful care must be taken to choose ingredients that are also within this category.
Most frequent commercial combinations include sandalwood, patchouli, rose, lavender or lemon peel. Because of its versatility and deep scent, it has become one of the most popular ingredients used in perfumery.