Vanilla comes from the cured seed pod (bean) of the vanilla orchid.
There are more than 100 varieties of vanilla orchids in the world but only 2 are used commercially:
Tahitensis and Planifolia (the main species harvested).
Both have their own characteristics and just like with coffee beans and wine grapes, there are significant taste differences.
This depends on where and how the vanilla plant is grown. But wherever the vanilla pods come from, they should have a rich, full aroma, be oily to the touch and sleek in appearance.
Vanilla Tahitensis:
Mainly found in Tahiti and Papua Guinea
Vanilla pods: big, plump, dark and thick
Fruity and floral aroma
Vanilla Planifolia:
Found in the Bourbon Islands (Mauritius, the Comoros, La Réunion and Madagascar)
Vanilla pods: long, creamy, oily skin and black
Strong vanilla aroma with vanillin overtones
Also found in Mexico, the origin of vanilla
Vanilla pods: Brown to black in colour
Spicy and wood fragrance aroma
Vanilla Planifolia can be found in Indonesia, India and West Indies