Washed (Wet) Coffee Processing

In our previous article we’ve dug into the questions of what coffee processing is and what the particular qualities of natural processing are. While on this subject, let’s talk about washed coffee and what the differences between natural and washed processing methods are.

‘Washed’ literally means that coffee is processed with the use of liquid. It is a more complex and advanced method that came into existence later than natural processing. So, let’s try to puzzle out what washed processing is.

What is the essence of washed coffee processing?

Straight after harvesting, coffee beans are separated from pulp with the use of special machines which remove red and yellow outer skin of a fruit leaving only its mucilage (the gummy substance that surrounds the bean and is extremely rich in proteins and sugars).

Afterwards, coffee is placed in special tanks for a period of 12-72 hours (depending on the temperature inside the tank). This stage gives rise to the process of fermentation with the above-mentioned mucilage in the lead: its nutrients penetrate into the bean, infusing it with sourness and spiciness.

At the same time, a concurrent process takes place: bacteria are stirred to activity; they start to eat sweet mucilage, contributing to its destruction. The environment in the tanks becomes acid under the influence of those bacteria, which also plays a significant role in the development of coffee taste. At this stage, it is extremely important to choose the right timeframe for fermentation: this can ensure a right balance of acidity for the future drink (which cannot be found in naturally processed coffee).

Nowadays many manufacturers like to experiment with fermentation duration. For example, the process can be accelerated by adding special bacteria to the tanks and regulating temperature and aeration. A longer fermentation process will facilitate the penetration of more mucilage substances into the bean, which will significantly affect the coffee taste. The most important thing here is to stop the process in proper time, since a spun-out fermentation will make coffee too sour.

When the mucilage is destructed, there is only so-called ‘coffee parchment’ left around the bean. After the fermentation is completed, the parchment is immediately processed with clean water which washes off the mucilage leavings. A system of special canal-locks with constantly circulating water is used for this purpose. Such washing helps to sort out coffee as well: ripe beans sink, while defective ones go up to the surface. The beans themselves become harder, which means that they can be dried now.

The drying process lasts from 10 to 22 days (depending on weather conditions). This stage is similar to natural processing: the same surfaces are used for drying — patios or African beds, beans also need to be constantly turned over for even drying and avoiding of molding, and at the end of the process the same amount of moisture remains in the bean — 11-12%. After the drying, the beans are also sent to ‘rest’ in special bags before halling. Such slow drying is considered to be the most efficient for a well-balanced coffee taste.

What is the difference between washed and natural coffee processing?

Making a long story short: in the case of washed processing, pulp substances do not penetrate into the bean, since pulp does not participate in it, and at the same time, some substances and minerals are washed out of the beans during the process. Therefore, taste and aroma characteristics of a particular coffee variety can be most brightly expressed only if wet processing is used; washed coffee has strongly-pronounced sourness, it is not as sweet as naturally processed coffee, yet it isn’t less aromatic.

So, the main difference is that washed processing focuses directly on the bean, and not on what is outside it.

How do farmers choose a processing method?

Again, the key factors are the geographical features and the preferences of a particular farm. It is simply impossible to dry coffee naturally in the regions with high humidity. The problem was solved on the island of Java in 1740 when washed processing was actually invented.

Nowadays wet coffee processing is more commonly used in Latin America and some regions of East Africa.

Is washed processing better than natural processing?

Many coffee lovers believe that only washed processing can fully reveal the inside potential of the bean, without any external influences. Such characteristics as the type and genetics of a particular coffee tree, weather parameters, soil quality and fermentation conditions are of great importance when we speak about washed processing, i.e. the country of origin, the environment and the direct actions of farmers equally affect the future coffee potential.

Washed processing is a rather complicated and sophisticated method which allows to reveal the palate fullness of the bean itself. And it is exactly because of this ‘purity of taste’ that many coffee enthusiasts go with this method for specialty coffee brewing.

But it is impossible to say with certainty that one processing method is better than another. It all depends on your taste preferences. If you are totally into sweet, fruity flavours and a very rich and full-bodied taste, go for naturally processed coffee; if you prefer sourness, bright aromas and a balanced taste (the taste palette of washed coffee may vary from tropical flavours to dark chocolate), washed processing will definitely be your cup of tea.

And you can always buy coffee processed by the method of your choice in our online store.

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