Coffee-Washed Processing Method

After being harvested, the coffee cherries will undergo a processing process to separate the kernel. There are 3 most common pre-processing methods: dry, wet and honey. So what is a coffee – washed processing method? How does the coffee wet processing method work?

What is a coffee – washed processing method?

The coffee wet processing method is also known as washing coffee. The coffee – washed processing method is a complicated preliminary processing process with steps: remove the meat surrounding the coffee beans; ferment coffee beans; dry to obtain green coffee beans.

Removing the flesh from the coffee cherries before it is dried reduces the risk compared to drying the cherries (such as further fermentation); resulting in higher value coffee beans. 

The coffee wet processing method requires a more complex process and stricter technical requirements than dry processing.

The coffee wet processing method requires a complex process

How does a coffee – washed processing method work?

A coffee – washed processing method includes the following four steps:

Sorting and processing coffee berries

The post-harvest coffee is put into the water tank to remove the floating pods along with other impurities; such as branches, leaves, mud mixed with ripe fruit…

Remove the flesh (skin) of the fruit.

After washing and sorting, the flesh of the coffee cherries is removed from the beans. Seed removal is done using a Depulper sheller.

These beans are then transferred to a clean water tank or water trough so that the flesh attached to the beans ferments and is removed.

The flesh of the coffee is high in pectin and sticks to the coffee beans. This fermentation will destroy the structure of the remaining coffee; causing them to be swept away by the water. Different manufacturers often use different amounts of water during fermentation.

Ferment

The fermentation time of Specialty coffee will depend on many factors. Especially the altitude and ambient temperature. In other words, the higher the temperature, the faster the fermentation takes place. However, if the bean coffee is left out for too long; bad taste will penetrate the beans.

In fact, to check if the coffee has fermented; Some manufacturers use a way of washing the beans between two fingers. If the surface of the grain is smooth, there is friction, and there is a rattling sound, the process is complete. Others experimented by inserting a long plant into the fermenter. When the plant is upright because it is supported by water containing a lot of colloidal pectins; fermentation has been completed.

Clean and dry

After fermentation, the coffee is washed to remove impurities from the beans. After that, the coffee beans are spread out to dry in the sun. During the drying process, stir regularly so that the coffee dries evenly; Avoid fermentation and mold.

In case of lack of sunlight or increased humidity, some manufacturers will use a dryer to dry the beans; reduce the moisture content of the seeds to 11% – 12%. However, the taste of sun-dried coffee is better than machine-dried coffee.

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Traits of a coffee – washed processing method

Advantages of a coffee – washed processing method

By using coffee – washed processing method, Coffee beans must undergo fermentation by enzymes themselves or with the participation of the enzyme system of microorganisms. Therefore, it helps to preserve the maximum amount of acid in pure coffee beans. Thereby ensuring the characteristic natural acidity of each type and creating a flavor favored by coffee connoisseurs.

Disadvantages of a coffee – washed processing method

To use the coffee – washed processing method; operator must be knowledgeable about berries. Furthermore, the fermentation process should be closely monitored to avoid the formation of undesirable flavors due to fermentation. At the same time, this method is also quite expensive: high costs, many machines and large amounts of water.

Wet processing beans

What kind of coffee should we use the coffee – washed processing method?

Normally, the coffee wet processing method is only applied to high-quality Arabica coffee, Typica or Bourbon and most of the Specialty Coffees popular in Central and South American or East African countries.

Coffee prepared by this method is usually more expensive; and coffee with low economic value can’t be used for wet processing. For example, Robusta coffee is much more acidic than Arabica coffee. When used for wet preliminary processing, it will leave a very bitter sour taste, causing sensory discomfort, so most have to be preliminarily dried.

Coffee at 43 Factory Coffee Roaster always uses a coffee wet processing method to ensure that the original coffee flavors will be remained intactly.