The wet processing method is a coffee processing procedure commonly used for coffee varieties with low acidity. This process includes the following stages: rubbing coffee cherries to remove the skin, soaking in water and fermenting to remove the mucilage from the beans, and finally drying to obtain parchment coffee. This is a very popular method in countries in Central and South America, and East Africa. In this article, let’s explore the wet processing method for coffee with Hello 5 Coffee.
Understanding the Wet Processing Method for Coffee
Unlike the dry coffee processing procedure which involves drying or roasting coffee cherries and then grinding them to obtain coffee beans, the wet processing method requires many complex stages along with a more modern machinery system and is usually only applied to high-quality Arabica coffee lines. Robusta coffee is generally not processed using the wet method because the coffee beans have acidic properties. When combining Robusta coffee with the wet processing method, it will result in a very harsh sour taste that is unpleasant to the senses. Therefore, Robusta coffee is usually dry processed.
Instead, Typica and Bourbon varieties with higher bean quality will apply this wet processing method to help preserve the maximum amount of acid in the beans along with the characteristic sourness that coffee connoisseurs love.
Coffee Processing Procedure Using the Wet Processing Method
Coffee Classification
Coffee on the tree often does not ripen evenly, so before putting it into the production process, it is necessary to select and classify the best coffee cherries and remove diseased or damaged ones.
After harvesting, coffee will be brought to the processing point and immediately soaked in a water tank to classify once more. Cherries that are dried, damaged will become light and float on the water surface. Meanwhile, ripe, evenly ripened cherries will sink into the water. In addition, branches, leaves, and impurities attached to the coffee cherries will also be removed.
Removing Coffee Skin
The skin of coffee cherries contains mainly very thick Cellulose, making it difficult for microorganisms to decompose under natural conditions. Therefore, before being put into the fermentation process, the coffee needs to be peeled.
This stage is considered the most important stage in the entire wet processing method. The stage of separating the coffee bean skin needs to be handled quickly to avoid the case of strange flavors developing in the coffee beans if left for a long time in the natural environment.
Fermentation to Remove Mucilage
The taste of coffee will be directly affected in this processing stage, so processors need to be very careful. After removing the fruit skin, the coffee needs to be immediately soaked in a water tank to carry out the fermentation process. The amount of water used for wet processing can vary but is usually a 1:1 ratio.
In some areas with scarce water resources, the fermentation process can take place naturally without soaking in a water tank. This method is also called semi-wet processing or honey processing (This method will be explored in a later article from Hello 5 Coffee).
Fermentation
The time for coffee fermentation will depend on many factors such as altitude and surrounding temperature. Coffee will ferment faster when the temperature increases. However, attention needs to be paid to the time in this stage to avoid affecting coffee quality.
To check whether the coffee has fermented properly, some producers have applied manual methods such as rubbing a coffee bean between two fingers. If the bean surface is smooth, slippery, has friction and creates a squeaking sound, then the process is complete. Another way to check is to insert a long stick into the fermentation tank. If the stick stands upright because it is supported by water containing a lot of Pectin gum created during the fermentation process, it means this stage is complete.
Washing and Drying Coffee Beans
After the coffee has successfully fermented, the coffee will be washed clean to remove impurities stuck to the beans. Then the coffee beans will be taken to dry in the sunlight. During drying, it is also necessary to regularly stir the beans evenly to avoid the situation where some beans are dried and some are damp or moldy.
In addition, a drying machine can be used in conditions of insufficient sunlight or high humidity. However, the quality of sun-dried coffee beans will be much better.
Characteristics of Coffee Processed by the Wet Processing Method
Advantages
With the wet processing method, producers have created a higher flavor quality for coffee. Because when wet processed, coffee beans will be fermented by the enzyme system in the beans or by microorganisms, helping to maintain better flavor quality. For bean varieties such as Arabica, this wet processing method helps maximize the flavor development in the beans.
Disadvantages
To be able to complete the wet processing procedure for coffee beans requires the practitioner to have high knowledge. In addition, the practitioner also needs to closely monitor all the transformations that occur during the fermentation process to ensure the best coffee flavor and quality. Besides that, implementing this method requires quite expensive costs, modern machinery systems and large amounts of water.
In the above article, Hello 5 Coffee has taken you to learn about the wet processing method and the coffee processing procedure according to this method. Most types of coffee processed by the wet method are rated as high-quality coffee because of the meticulousness and care in the processing process, while also helping the coffee develop its maximum flavor.
Read more: 3 Popular Green Coffee Bean Processing Methods
In addition, if you have a desire to become a professional Barista, want to learn about coffee, how to make coffee, or want to start your own business, don’t hesitate to register for Hello 5 Coffee’s classes.
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