Ripe cherry is depulped within hours, the bean is held in tank until the mucilage loosens, then washed clean and dried. It is the method Colombia built its name on, and the suave in suave colombiano describes what it does rather than how it sells.
Nothing is hidden by it. A washed lot reports the hillside and the picking with very little between them and the cup, which is why the house leads with it and why a thin coffee has nowhere to go.
What happens in the tank
Fermentation here is spontaneous, driven by the microbes already on the fruit. Cenicafé records yeasts, lactic acid bacteria, enterobacteria and others, with the enterobacteria giving way to Leuconostoc, Lactobacillus and Acetobacter as the hours pass. Pectins break down, sugars form and acidify, and the mucilage loosens its grip on the parchment.
The pH tells the story: in a dry tank the mucilage falls from about 5.36 to 3.45 across sixteen to eighteen hours. Under water it falls less far, to about 4.23, which is why submerged fermentation runs slower and more forgivingly.
One detail is left out of most descriptions. The mucilage is not fully broken down in those fourteen to eighteen hours. The tank only loosens it enough to wash away. Washed coffee does not have the fruit removed so much as taken off early.
Where it goes wrong
Left too long, the same process that makes a clean cup makes a ruined one. Cenicafé names the faults directly: granos vinagres, vinegar beans, and the stinker and onion notes that follow. A tank run to seventy-two hours instead of sixteen is not a more developed coffee, it is a defective one.
This is the argument for the mill over the method. A washed lot is only as clean as the picking that fed it and the discipline that timed it.