1. But farmers can also grow criollo or cacao plants.

2. The pure variety of the Criollo tree is found mainly in its native Ecuador and Venezuela.

3. The second study found that the Criollo tree, which produces the world’s finest chocolate, has around 29, 000 genes.

4. However, Criollo cocoa accounts for only 10 % of the world crop.

5. French researchers led a separate effort focusing on the high-quality Criollo variety.

6. Purists know that the rarest and finest of the three varieties of cocoa bean is the criollo – chocolate snobs lovingly describe its lingering aftertaste as featuring vanilla, caramel and nuts.

7. Many growers prefer to keep hybrid cacao trees that are tougher but produce lower-quality chocolate than the Criollo tree, which was domesticated 3, 000 years ago.

8. There are two quite different basic classifications of cocoa, under which practically all varieties can be categorised: Criollo and Forastero cocoas .

9. Finally, there is the Trinitario variety of cacao, which is a cross between Criollo and Forastero.