What does tonka bean smell like? Vanilla's wilder cousin

Tonka bean is a small, wrinkled black seed with a big reputation. It smells like vanilla, almonds and fresh hay all at once. It also gave the world coumarin, the molecule that helped turn perfume from a craft of natural oils into the modern art it is today.

What does it smell like?

Warm, sweet and nutty, with a dry, grassy side. In one breath you might notice:

• Hay: the smell of freshly cut, sun-dried grass
• Almond: sweet, like marzipan or bitter almond
• Vanilla: a soft, sugary warmth
• Tobacco: a dry, cured-leaf note
• Caramel and cherry: faint, toasty and fruity hints in the background

Tonka is less sugary than vanilla. It feels drier, nuttier and a little more "outdoors".

Where it comes from

Tonka beans are the seeds of Dipteryx odorata, a tall tropical tree from the rainforests of northern South America. Venezuela and Brazil produce most of the world's supply. Venezuela's Caura River region is especially known for it. Nigeria is a smaller source.

The tree grows a fruit with a single seed inside. That seed is the tonka bean.

How it's made

1. Harvest. The fruits are gathered after they fall, and the seed is cracked out.
2. Drying. The beans are dried in the shade for a few days.
3. Curing. Traditionally, the beans are soaked in rum or another strong alcohol, then dried again. This helps release coumarin, which can form as tiny white crystals on the skin of the bean.
4. Extraction. For perfume, the cured beans are treated with solvents to make a tonka absolute: a thick, dark, very fragrant material.

The key molecule: coumarin

The main smell of tonka comes from coumarin. Coumarin is also found in sweet clover, sweet woodruff, some grasses and cassia cinnamon. It is the reason freshly cut hay smells sweet.

Its name comes from coumarou, an old French word for the tonka tree. Chemists first isolated it from tonka beans in the early 19th century.

A short history of tonka bean

• Early trade: Tonka beans were known in South America long before they reached Europe. Once traded abroad, they were prized for scenting things like tobacco.
• 1868: English chemist William Henry Perkin made coumarin in the lab. It was one of the first natural smell molecules ever recreated by chemistry.
• 1882: Perfumer Paul Parquet used synthetic coumarin in Fougère Royale for the house of Houbigant. It is widely seen as one of the first modern perfumes, because it used a lab-made molecule as a key part of its structure. It also gave its name to a whole perfume family, the fougère (French for "fern"), built on lavender, coumarin and oakmoss.
• 1889: Jicky by Guerlain also used coumarin, alongside vanillin and lavender.

Fougère perfumes are still the backbone of many men's fragrances today.

Tonka in modern perfume

Tonka and coumarin are everywhere in modern perfume. They give barbershop fougères their warm, clean base. They round off amber and vanilla perfumes. And they add a nutty sweetness to gourmand scents.

Jean Paul Gaultier's Le Male (1995) is a famous example. It mixes lavender with vanilla and tonka for a warm, clean, sweet smell that became a global best-seller.

Rules and safety

Coumarin is regulated, but it is not banned in perfume.

• In food: The US Food and Drug Administration banned coumarin as a food additive in 1954, after high doses damaged the livers of test animals. That is why tonka beans cannot legally be sold as food in the US. The EU allows small amounts in food.
• In perfume: Coumarin can cause skin allergies in some people. The International Fragrance Association (IFRA), which sets safety standards for the industry, limits how much can be used. In the EU, coumarin is one of the fragrance allergens that must be named on the label above a certain amount. If you see "coumarin" on your bottle's ingredient list, that is why.

Coumarin is not the same as the blood-thinning drug warfarin, though warfarin was later developed from a related compound.

Real vs synthetic tonka

Most of the "tonka" smell in perfume comes from synthetic coumarin, which is cheap, clean and consistent. Natural tonka absolute is richer. It adds tobacco, caramel and dried-fruit sides that coumarin alone cannot give. High-end perfumes often use both.

What tonka pairs well with

• Vanilla: the most natural partner. Together they feel warm and edible.
• Lavender: the classic fougère pairing. Clean, fresh and slightly sweet.
• Tobacco: turns tonka dry, dark and smoky.
• Almond and cherry: bring out its marzipan side.
• Amber and benzoin: make it resinous and cosy.
• Woods like sandalwood and cedar: keep it smooth and dry.

Perfumes to try

• Tonka Impériale by Guerlain: tonka with almond, tobacco and honey. Rich and smooth.
• Tonka 25 by Le Labo: drier and woodier, less sweet than most.
• Le Male by Jean Paul Gaultier (1995): lavender, vanilla and tonka. A modern classic.
• Jicky by Guerlain (1889): lavender, coumarin and vanilla, with an animal edge. A piece of history.
• Fougère Royale by Houbigant: the modern version of the perfume that started the fougère family.

How to wear tonka

• Tonka is a base note, so it lasts long and appears most in the drydown.
• Sweet tonka perfumes suit autumn and winter. Lavender-tonka fougères work all year.
• It is very skin-friendly and easy to wear to work.
• If you find vanilla too sugary, try tonka instead.

Who will love it

People who like warm, cosy scents but want something drier and less sugary than vanilla. Fans of barbershop fougères, tobacco perfumes and nutty gourmands will feel right at home.