The three main varieties of cacao beans used in chocolate are criollo, forastero, and trinitario.
Representing only five percent of all cocoa beans grown, criollo is the rarest and most expensive cocoa on the market,
and is native to Central America, the Caribbean islands and the northern tier of South American states.
There is some dispute about the genetic purity of cocoas sold today as criollo, as most populations have been exposed to the
genetic influence of other varieties.
Criollos are particularly difficult to grow, as they are vulnerable to a variety of environmental threats and produce low yields of cocoa per tree.
The flavor of criollo is described as delicate yet complex, low in classic chocolate flavor, but rich in "secondary" notes of long duration.
The most commonly grown bean is forastero, a large group of wild and cultivated cacaos, most likely native to the Amazon basin.
The African cocoa crop is entirely of the forastero variety. They are significantly hardier and of higher yield than criollo.
The source of most chocolate marketed, forastero cocoas are typically strong in classic "chocolate" flavor, but have a short
duration and are unsupported by secondary flavors, producing "quite bland" chocolate.
Trinitario is a natural hybrid of criollo and forastero. Trinitario originated in Trinidad after an introduction of forastero to the local criollo crop.
Nearly all cacao produced over the past five decades is of the forastero or lower-grade trinitario varieties.