Wet Process

The wet process, commonly referred to as the washed process, is one of the most prevalent methods for preparing coffee for export. In this method, the coffee cherries are harvested and immediately put through a depulping machine to remove the outer skin and fruit flesh. The remaining beans, still covered in a sticky layer of mucilage, are then placed in fermentation tanks. During this stage, natural enzymes break down the mucilage, a process that can take anywhere from 12 to 72 hours depending on the temperature and local practices.

What is the wet process's impact on flavor? By removing the fruit flesh before drying, the bean is allowed to dry in a 'clean' state. This prevents the flavors of the fermenting fruit from penetrating the bean, which is common in natural or honey processes. As a result, washed coffees are typically characterized by their clarity, high acidity, and distinct flavor notes that reflect the coffee's terroir—the specific soil, altitude, and climate where it was grown.

For the coffee professional, the wet process is a technical endeavor that requires significant water and infrastructure. Washing stations must manage fermentation carefully to avoid defects like over-fermentation or 'stinker' beans. After fermentation, the beans are washed with clean water to remove any remaining mucilage and then dried on raised beds or mechanical dryers until they reach the ideal moisture content, usually around 10-12%.

In practice, the wet process is the gold standard for highlighting the 'origin character' of a coffee. If you are looking for a cup that is bright, crisp, and clean, a washed coffee is almost always the best choice. It is the method of choice for many of the world's most prestigious coffee-growing regions, including Kenya, Colombia, and parts of Ethiopia, where the goal is to showcase the unique, delicate nuances of the bean without the influence of heavy fruit-forward processing.