Tonka bean

The tonka bean is the dried seed of the South American tonka tree, Dipteryx odorata: a spice that smells of vanilla, bitter almond, and hay, and is added to desserts in tiny amounts using a grater.

The tonka bean is the dried seed of the South American tonka tree Dipteryx odorata: a spice that smells of vanilla, bitter almond, and hay, and is added to desserts in tiny amounts via a grater.

The Duden dictionary keeps it brief, calling it a flavoring agent, with the word itself being Caribbean in origin. It comes from Galibi, a language spoken by the indigenous people of French Guiana, where it refers to the tree. The tree belongs to the Fabaceae family, which is why the seed is called a "bean," even though no one cooks it like one. Its old genus name, Coumarouna, goes back to the Tupi word *kumarú*, from which the substance that carries the entire aroma takes its name: coumarin. The tree is native to northern South America, in the Orinoco river basin; most beans today come from Venezuela and Nigeria. The fruit has two wings, hence *Dipteryx*, and *odorata* simply means fragrant.

The aroma must first be awakened. In the fresh bean, the coumarin is bound and smells of little. That is why producers soak the seeds in rum for 24 hours and then dry them; this triggers a fermentation process that releases the substance, and in the end, the bean can contain up to 10 percent coumarin. Under the black, wrinkled skin, it then sits as a fine white frost, which looks like mold but is not: coumarin crystals. The Altes Gewürzamt in Klingenberg am Main sells its beans exactly like this, soaked in rum for 24 hours and fermented, and describes the bouquet as having notes of bitter almond, woodruff, vanilla, and caramel.

What does tonka bean taste like?

Sweet, heavy, and very strong, with a hint of hay and a slightly bitter aftertaste, according to technical literature. The Bavarian State Office for Food Safety summarizes the scent of coumarin in four words: sweet, vanilla-like, herbal, spicy. Anyone who runs a bean over a grater will smell vanilla first, then marzipan, then something reminiscent of freshly cut grass. That is the woodruff in the aroma, as coumarin is also found in it and in cinnamon. The quantity determines the taste: a hint is warm and round, a touch too much tastes like a pharmacy and perfume, as the Altes Gewürzamt warns itself. That the scent is also popular outside the kitchen is shown by history: for a long time, the bean was primarily used to flavor pipe tobacco, and in perfumery, coumarin still stands for the warm, powdery note that soaps and candles with the word "tonka" in their name carry.

Which spice does the taste of the tonka bean resemble?

Vanilla, so closely that the tonka bean has replaced it in many kitchens. The Hessian consumer portal describes it as a spice that is grated like nutmeg and tastes of vanilla. In gastronomy, its rise began around the turn of the millennium, especially in Germany, and since then it has been used in creams, ice cream, and puddings that were previously flavored with vanilla. The difference lies in the finish: vanilla remains floral and clean, while tonka adds bitter almond and hay, making it darker. Those familiar with both will also taste a kinship to woodruff and cinnamon in the tonka bean, as all three carry the same aromatic compound. It behaves like nutmeg on a grater: hard, dry, and yielding, and after grating, it goes back into the tin. A test when buying: the bean should be firm and wrinkled and smell immediately upon grating; if it smells of little, it has already lost its aroma. If you are buying it for the first time, take the smallest tin and grate less than the recipe says for your first dessert.

What is tonka bean used for?

For anything containing cream, milk, sugar, or chocolate. Panna cotta, crème brûlée, mousse, and vanilla ice cream are classics, along with rice pudding, caramel sauce, plum compote, and Christmas stollen. It can be used more sparingly in savory dishes, but it works: with fish, in soups, with lentils and vegetables, with game and foie gras, and even in tomato sauce. The technique is to use a fine grater directly over the dish, just a few strokes, then taste. Or, you can coarsely break a quarter of the bean, let it steep in 500 milliliters of cream, and remove the pieces before serving; the quarter is enough for four dessert portions, and even less for chocolate and ice cream. A bean weighs almost nothing and will accompany you through a year of desserts. A recipe idea: bring cream to a boil with a quarter of a bean, let it steep, fish out the pieces, thicken with sugar and a little gelatin to make panna cotta, and chill; serve with a spoonful of plum compote containing another dash of tonka. The dessert tastes of a vanilla you don't recognize, and that is precisely its charm.

There are clear rules regarding the aromatic substance, and they confirm the need for careful dosage. Coumarin may not be added to food as a pure substance; for foods where it is present via flavorings or ingredients, the Flavoring Regulation specifies maximum levels: 5 milligrams per kilogram in desserts, 15 in fine baked goods, 20 in breakfast cereals, 50 in seasonal cinnamon pastries such as gingerbread and cinnamon stars. For the kitchen, this only means what the aroma demands anyway: grate sparingly, do not eat the bean itself, and do not overload stollen with both tonka and cinnamon.

It should be stored like nutmeg: whole, dry, dark, and tightly sealed. Once ground, it quickly loses what makes it special; it is best to grate it directly over the pot. Buying in small quantities is worthwhile: the 30 grams from the Altes Gewürzamt is a supply for many months, and an opened tin lasts as long as it remains closed. Oberhöller in the Sarntal valley stirs 0.1 percent tonka bean into their almond cream, and La Sablésienne bakes their butter sablés with 0.3 percent natural tonka bean flavoring; both figures show how little of it is needed to perfume an entire jar or tin.