tonka bean the fruit of a leguminous tree, Dipteryx odorata, native to the forests of Colombia, Venezuela, Guiana, and Brazil. The beans are mainly gathered from the wild in Venezuela, but there has also been some cultivation. The value of the beans has been due to their containing coumarin, which has an aroma between those of hay and of vanilla.
The dried beans (one to each pod) are cured in rum and then dried again, when they become coated with a white deposit of coumarin. Until shortly after the Second World War they were in considerable demand as a source of flavour for liqueurs, confectionery, and chocolate. However, the use of natural coumarin in food was banned in the USA in 1954, and the use of tonka beans restricted to perfume. In other countries they have now been largely replaced by synthetic coumarin and vanilla.