The origin of Theobrama Cacao has been traced to South America, where the two original strains appear to have inhabited virtually separate universes until the 18th century. The Forastero geneotype made its home in the Amazon River basin, growing lush and free in the rainforest. Further away, in the Venezuelan foothills of the Andes mountains, south of Lake Maracaibo, grew a more flavorful, but delicate strain called Criollo. With little travel penetrating the thick forests of the Amazon, Forestaro remained virtually unknown as Criollo moved north into Mexico by the end of the first millennium B.C. There it was revered by indigenous civilizations and eventually discovered at the Aztec court of Moctezuma by the Conquistadors. As the Europeans spread cultivation to other regions within the narrow latitudinal band 20 degrees either side of the equator, cacao genetics remained relatively homogenous. However, beginning in the 18th century, Forastero genes began to appear, resulting in a cacao that while heartier, was markedly inferior in taste.

The natives of the Amazon rainforest had long valued the Forastero strain of cacao for its fruit, but had yet to convert it to chocolate. The thick-skinned fruit was very prolific with flat beans a dark purple in color. This was markedly different than Criollo, with its thin-skinned pods and light pink or white beans. The flavor of the Forastero was harsher and more acidic than Criollo. While powerful in flavor, Forastero is one-dimensional without Criollo's mellowness and complexity. However, Forastero's traits of resilience and resistance became essential when a series of diseases leveled cacao plantations in the 1720's. Trinadad, an island of thriving cacao plantations was particularly hard hit. When devastated farmers replanted, they chose seedlings of Amazon Forastero in hopes of strengthening their crop. This strain soon crossed with the few remaining Criollo trees that escaped the blight, forming a third distinct strain of cacao, Trinitario, named after its island origin. Blending the best of its parents, the Trinitario is better tasting than its Forastero father and less susceptible to disease than its mother, Criollo.

Since then, a million permutations, crossings and re-crossings have made the chocolate landscape extremely complex. However, a pattern of Forastero dominance soon emerged, and now more than 90% of the cacao used worldwide is of this genetic make-up.