Sweet woodruff vs Tonka bean
The short answer
The same aroma for the same reason: both smell of hay, vanilla and almond because both carry coumarin. They differ in how much and how it is used. Tonka is a tropical seed dense with coumarin, grated in tiny quantities, and prohibited as a food ingredient in the United States; woodruff is a European herb whose coumarin only appears as it wilts, used by brief infusion in May wine and syrups. A little tonka can stand in for woodruff in a dessert; neither is a casual ingredient at quantity.
Side by side
| Sweet woodruff | Tonka bean | |
|---|---|---|
| Botanical identity | Galium odoratum (L.) Scop. | Dipteryx odorata (Aubl.) Willd. |
| Part used | leaf, stem | seed |
| Origin | Native to Europe, extending into western Asia and North Africa, in shaded woodland. | The Amazon and Orinoco basins of northern South America, where the tree grows wild and where most beans are still gathered rather than farmed. |
| Flavour notes | hay, vanilla, almond, sweet, faintly bitter | sweet, hay-like, almond, vanilla-adjacent |
| Heat | Scoville does not apply | Not established |
| Flavour | Sweet-smelling and faintly bitter. Infused into wine or syrup it gives a hay-and-vanilla perfume; chewed, the leaf itself is slightly bitter and not pleasant, which is why it is steeped and removed rather than eaten. | Sweet and aromatic rather than tasting of much on the tongue — the effect is almost entirely aromatic. Grated over a dish it reads as vanilla with hay and almond behind it, and it turns bitter and soapy if overdone, which happens easily. |
| Aroma | Fresh: faint and green. Wilted or dried: sweet new-mown hay, vanilla and almond, the unmistakable smell of coumarin. | Intense and immediately recognisable: sweet hay and new-mown grass over vanilla, with almond and a cinnamon edge. It is far stronger than its size suggests and a single grated bean will scent a room. |
Can you swap them?
Substitution is directional: the answer is often different in each direction, and both are recorded.
Tonka bean
SituationalThe same compound, coumarin, carries both aromas, so the hay-and-vanilla character comes through. Tonka is far stronger and is grated in tiny amounts.
| Flavour | Aroma | Colour | Heat |
|---|---|---|---|
| close | close | different | similar |
Works for
- Custards and ice cream
- Syrups
Does not work for
- Anywhere in the United States, where tonka is prohibited as a food ingredient
- May wine, where the spring herb is the custom
Both carry coumarin, and a substitution that raises the dose defeats the purpose of using woodruff sparingly; a few gratings of tonka at most.
Which should you buy?
Sweet woodruff
—
Tonka bean
There is no real decision to make: buy whole beans, because that is essentially all that is sold and because the whole bean is the better product on every axis that matters. It keeps for years where ground spice would be flat in months, it is grated to order in the quantity the dish needs, and — the part that matters most with this particular spice — it can be infused and lifted out, which is the only reliable way to stop. Tonka is easy to overdo and turns soapy and bitter when overdone, so a form that lets the cook remove it mid-way is worth more here than in almost any other entry in this catalogue.
Full detail on sweet woodruff and tonka bean, including evidence grades and sources for every claim above.