Days one and two: the pulp breaks down
Wild yeasts in the air start eating the sugary white pulp around the beans. The box warms up and juice runs out through the slats. By the end of day two it smells like ripe fruit.
Days three and four: the heat rises
After the first turn, air gets in and different bacteria take over. The temperature climbs past 45 degrees. The heat and acid kill the seed, so it can no longer sprout, and that is what lets the flavour develop.
Days five and six: brown inside
Inside the bean, purple turns to brown. Bitter compounds soften and the building blocks of chocolate flavour form. We cut test beans every morning to see when to stop.
Why we do not rush it
Many beans are sold after two or three days, or not fermented at all. They are cheaper to produce, and they taste flat and harsh. Six full days is the single biggest reason our bars taste the way they do.
You cannot fix a badly fermented bean in the factory. The flavour is made on the farm.