Wet method of coffee processing

Coffee processed by the wet method is called wet processed or washed coffee. At least 50 percent of all coffee in the world is processed wet, and for most specialty coffee producing countries this is the preferred processing style. It is also the most economically intensive style of coffee processing.

Wet method processing usually involves placing the beans into water for softening and then mechanically de-pulping the beans using a pulper.

In the wet process, water is used to wash the skin and pulp off the fruit of the coffee cherry. The coffee cherries are sorted by immersion in water. Bad or unripe fruit will float and the good ripe fruit will sink. The skin of the cherry and some of the pulp is removed by pressing the fruit by machine in water through a screen.

After de-pulping, the sticky seeds will usually go into a fermentation tank for 12-36 hours. After the fermentation process, the coffee is then rinsed free and clean of any residuals with water.

The beans are then dried out in the sun using either raised beds made of screens, large flat patios, or with mechanical dryers. After these steps, the coffee is rested and then milled, resulting in a clean, polished bean ready for the roaster.

Wet processing in general is said to produce a clean taste in the cup of brewed coffee, and also helps to ensure a shining, bright acidity. The washing process allows consumer to better taste the flavor of the coffee, as washing doesn’t impart a lot of flavors to the coffee.

After a coffee crop is processed and then sorted and grades, most of the coffee beans are usually bagged in 132 or 154 pound coffee sacks.
Wet method of coffee processing

Green Coffee Bean Processing: Wet Method

Green Coffee Bean Processing: Wet Method
The production of green coffee beans involves successive removal of the outermost red skin and the pulp of the coffee berry, followed by removal of the mucilage, parchment covering, and finally the silver skin surrounding the green coffee bean.

There are are two methods currently used to produce green coffee beans; “wet” and the “dry” methods.

However, and alternative nomenclature is often used: “washed” and “natural processing”, respectively, and to avoid a misunderstanding it is often necessary to obtain a definition of the processing used on a given batch of coffee beans.

This is relatively intricate and is best carried out with uniformly ripe coffee berries that are still firm.

To achieve this uniformity the coffee berries are selectively handpicked.

As soon as possible they are sorted further in a water flotation system and sent directly to a pulping machine. Here the berries have the outermost skin and pulp removed and the mucilage layer is exposed.

Removal of mucilage ios brought about in concrete fermentation tanks, where the beans are slurried with water, A fermentation occurs that is mainly due to lactobacilli and yeasts.

Enzymes are produced that dissolve away the mucilage. The beans are washed free from the mucilage and the parchment layer is exposed.

Now the beans are dried in the sun or more usually in mechanical dryers.

Hulling completes the process. The parchment layer and most of the silverskin are removed in a hulling machine. Green coffee beans produced in this way are now ready for storage and shipping.
Green Coffee Bean Processing: Wet Method