Wet Process

What is done with the skin and mucilage from the coffee cherry is what determines or defines the processing method.

The wet, or washed process is a method of removing the mucilage from the cherries using water in one of two possible ways:

  1. The cherries can be mechanically de-pulped to remove the skin and some mucilage and the beans are then fermented in water tanks to remove the remainder of the mucilage, or
  2. The cherries are processed by an aquapulper, which mechanically removes the mucilage without the need for fermentation.

Here is a video of an aquapulper in action:

Coffee processing - aquapulper in Gautemala from Coffee Real Ltd on Vimeo.

The fermentation process is one way to affect a coffee’s flavor at origin.  Doing it right can add a bit of lively acidity and even a hint of wine-like attributes like floral and fruity aromas and flavors to a coffee.  Doing it wrong can make the ferment flavors and aromas dominant, even overbearing and unpleasant.  Fermentation done properly is one way a mill or washing station can add uniqueness, and thus value to the end product.