Preliminary processing of coffee is an important step in the coffee production process. There are much different preliminary processing. Coffee semi-washed processing is a combination of dry and wet methods. Let compare semi-wet processing with other methods.

What is coffee semi-wet processing?

Origin of coffee semi-washed processing

Coffee semi-washed processing was first developed in Brazil in the 1970s and was created as a way to improve coffee quality while reducing production costs.

It was nearly impossible to find a unified name for this type of coffee prepared by this method when it first appeared. It is sometimes known commercially as semi-dry, semi-wet or hybrid coffee, and each region (and period) for which this technique has a different name.

The early 1950s to 1980s

The Institute of Agronomy Campinas (IAC) in Brazil was the first to experiment with coffee semi-washed processing, known as the natural grinding technique, in the early 1950s. It was not until the 1980s that some farmers in the region. Nam Minas Gerais did it on a commercial scale for the first time with positive effects on quality.

This led to widespread adoption after Pinhalense, a well-known industrial equipment company, developed milling machines, installed pilot plants in different Brazilian production regions, and introduced new products for factories at home and abroad. The first products from the semi-wet coffee processing method in Brazil were called “Cereja Descascado” or CD.

Late 1980s to 1990s

After a rather slow start in Brazil in the late 1980s. By the 1990s, this new process began to become widely used. Although the semi-wet processing system was originally developed to solve quality problems, it is also used to exploit the more distinctive flavors and qualities of coffee beans.

Nowadays

Coffee semi-washed processing gradually spread from Brazil to other regions such as Central America, where the method is known as the honey pre-processing method. The coffee here is dried for a long time with a higher moisture content, resulting in a richer and richer flavor.

Why does coffee semi-wet processing become popular?

Coffee semi-washed processing

– In this technique, the outer skin is removed mechanically, like wet pre-processed coffee, but the mucilage is partially left on the surface of the coffee beans during the sun drying process for fermentation.

– The second drying step begins when the coffee turns dark green with a moisture content of about 10% – 12%, similar to the standard moisture level of semi-wet coffee. Depending on the time of the drying process, the corresponding colors from yellow, red, and black will be produced. This processing technique, featured in Brazilian, Indonesian and Vietnamese coffees, enhances the coffee’s flavor and intensity.

– The phrase “preliminary honey” leads many people to think that the honey is used to make coffee or that the coffee itself tastes like honey – but that is not the case. This process, like coffee, gets its name from the sticky, honey-like feel of the coffee beans before being dried. When the bean is separated from the pod, it is covered with a mucous membrane that, when dried, the coffee beans will continue to reabsorb moisture from the air and become quite sticky.

Semi-washed coffee is also known as honey pre-processing or pods steeping method

Classification of semi-washed coffee

Semi-washed pre-processing is a method that requires controlled fermentation as well as a sophisticated degree of processing. Therefore, coffee processed by the honey method has a relatively high cost. Even the price will increase according to the color of the coffee beans.

Yellow

Yellow indicates the coffee beans that are most exposed to light. More light means more heat; As such, coffee of this color usually takes about a week to reach the standard moisture content of 10% – 12%. Moreover, drying time always depends on weather conditions, temperature, humidity.

Red

The red coffee is usually dried for two to three weeks and left to dry in the shade. If it is sunny, farmers will have to cover the coffee to reduce exposure.

Black

Black coffee shows the longest drying process with a minimum of two weeks, and is dried in a greenhouse out of direct sunlight. This is the most difficult fermentation to control and the most expensive coffee of all.

Yellow indicates the coffee beans that are most exposed to light

Where is the coffee semi-washed processing most used?

Evaluate coffee semi-washed processing

The most obvious benefit of semi-wet pre-processing is improved drying efficiency, as well as flavor characteristics through fermentation. On the other hand, this technique contains more risks during fermentation compared to wet processing.

Advantages

Completely different from the wet pre-processing process which uses a large amount of water and is easy to waste environmental resources, the semi-wet coffee process only takes a smaller amount of water. That is a plus in coffee processing for some places where water is extremely scarce. Not only that, the semi-wet pre-processed coffee beans also create a rich flavor that is appreciated. Especially for coffee varieties with high flavor quality such as Arabica, this method helps develop maximum flavor in the bean.

Defect

With more mucilage on the grain, the possibility of fermentation and spoilage is higher during drying. Therefore, semi-wet coffee needs to strictly control the fermentation process and the taste also limits the freshness of the finished cup of coffee.

Method of roasting semi-washed processing coffee beans

When roasting semi-washed coffee beans, it is important to maintain a consistent roast throughout the batch. This can be difficult, as coffee beans absorb heat differently depending on size, moisture content, and grain structure.

Semi-washed coffee beans need to be roasted at a lower temperature than wet beans and for a shorter period of time. This allows the beans to retain some of their natural oils, giving the coffee a richer flavor.

In general, Specialty coffee roasters feel that the semi-washed beans are harder to work with, but the end result is a cup of coffee with a much richer and richer flavor.

Roasting semi-wet coffee beans requires more preparation

The characteristic flavor of semi-washed pre-processed coffee

The semi-washed pre-processing process results in coffee with a deeper sweet flavor than the wet processing but leaves very little fruit flavor in the beans.

The semi-wet process also results in coffee with a thicker body and richer flavor than the dry pre-processing.

Common flavor notes associated with semi-wet coffee include chocolate, caramel, spice, and nuts.