Vanilla is the only edible fruit of the orchid family, the largest family of flowering plants in the world. It's a tropical orchid, and there are about 150 varieties of vanilla, but only two types - Bourbon and Tahitian -- are used commercially.
Vanilla grows within the 20-degree band either side of the Equator and is native to the Americas. "Vanilla planifolia" grows on the Atlantic Gulf side of Mexico from Tampico around to the northeast tip of South America, and from Colima, Mexico to Ecuador on the Pacific side. It also grows throughout the Caribbean.
Vanilla is the world's most labor-intensive agricultural crop, which is why it's so expensive. It will take up to three years after the vines are planted before the first flowers appear. The fruits, which resemble big green beans, must remain on the vine for nine months in order to completely develop their signature aroma. However, when the beans are harvested, they have neither flavor nor fragrance. They develop these distinctive properties during the curing process.
When the beans are harvested, they are treated with hot water or heat and are then placed in the sun every day for weeks-to-months until they have shrunk to 20% of their original size. After this process is complete, the beans are sorted for size and quality. Then they will rest for a month or two to finish developing their full flavor and fragrance. By the time they are shipped around the world, their aroma is quite remarkable!
BOURBON VANILLA is named for the islands now known as Reunion and the Comoros, but in the early 19th century were called the Bourbon Islands. The Bourbon vanilla plant stock originally came from Mexico. Bourbon vanilla and Mexican vanilla are basically the same.
TAHITIAN vanilla also originally comes from Mexican plant stock, but it mutated at some point in the last fifty to sixty years and became its own species. It is significantly different from Bourbon and Mexican vanilla.