Acre is a state located in the center of the Amazon Rainforest, in northwest of Brazil, bordering both Bolivia and Peru. Intense extractive activity in the rubber industry, which reached its height in the early 20th century, attracted Brazilians from many regions to the state, though it remains one of the least populated. Agriculture beyond the subsistence level is uncommon in Acre; almost all of the cacao harvested in the region comes from wild-growing native varietals collected by local indigenous peoples.

Purús is one of those ten evolutionarily unique types identified in 2008, using samples collected throughout the Americas over the previous century. Samples proven to be of the purús genetic cluster were collected from trees growing wild along the banks of Brazil’s Upper Amazon rivers, including the Rio Purús, after which the cluster is named. Pure examples of purús in modern chocolate express as floral and herbal; but they’re exceedingly rare, as the cacao is almost always wild-harvested from the Brazilian Amazon, the same region as the original samples were collected decades before.