1 · Twenty seconds of heat. The cherries are brought to 80 °C for twenty seconds, then plunged cold. It is, precisely, a pasteurization: it strips off the wild yeast and bacteria the fruit picked up in the field, and it frees the sugars the ferment will feed on. Most natural coffees are fermented by whatever happened to be in the air that day. This one isn’t.
2 · The farm’s own culture. With the cherry clean, the only thing left to drive the ferment is a starter the farm made itself — its mosto, the fermented juice of its own coffee cherries, held back from the previous Caturra harvest and layered over this one. A sourdough starter, for coffee. No foreign fruit, no infusion, no flavoring: the native microorganisms of Los Nogales, carried forward batch to batch.
3 · Ninety-six hours, sealed and cold. Four days in a sealed tank held at a steady 18 °C. Long enough to build the banana, rose and candied citrus. Controlled enough that the Caturra and the 1,900 metres still come through underneath it. That is the whole point of the exercise — the process doesn’t cover the farm, it amplifies it.