If you don’t know how to process coffee beans, don’t just say you know coffee.

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People did not "drink" coffee at the beginning, but "ate" it. In other words, they directly ate the fruits of the coffee tree (called coffee cherries because the size and color of the fruits are like cherries). To be more precise, they ate the coffee pulp (coffee seeds are too hard, so of course they are spit out directly).

Later, Ethiopian soldiers dried the whole coffee cherries and chewed them directly for easy carrying. Today, many coffee producing areas in Africa still use dried coffee cherries as snacks. They are sour and crunchy, and taste like dried fruit. Just put a handful in your pocket and chew a few when you feel tired. It is quick and convenient.

It takes 3-5 years for a coffee tree to bloom and bear fruit. When the fruit is ripe and red, farmers can prepare to harvest it. The red fruit looks like a miniature cherry, so small and cute, so we call these delicate fruits "coffee cherries".

The essence of coffee beans is the seeds of the plant. After the coffee cherries (commonly known as coffee fruits) are ripe and picked, they need to go through a series of processing steps before they can go from seeds to cups.

Coffee Cherry

Here we will introduce you to the internal structure of coffee cherry

The coffee beans we use to make coffee are actually the seeds inside the coffee fruit.

The outer layer of the seed includes structures such as the exocarp, pulp, pectin, endocarp and silverskin. The purpose of processing is to remove these external structures to obtain the coffee seeds inside.

Green beans

Sun exposure method

The sun drying method is the oldest processing method. According to historical records, the Arabs began to use the sun drying method to process coffee berries more than 1,000 years ago in the 11th century. Because of the refreshing effect of coffee, when coffee was introduced from the Arab world to the West, it was also called "the wine of the Arabs."

Process

1. Remove floating beans

Pour the coffee beans into a large tank. The underdeveloped and inferior beans will float to the surface, while the mature and plump fruits will sink to the bottom. At this time, remove the floating beans on the water surface, and the step of removing the floating beans is completed.

Picking floating beans

2. Sun exposure

The coffee cherries are evenly spread in the drying area and turned over several times a day. This process usually lasts about 2-3 weeks, depending on the local climate. When the moisture content of the coffee beans drops to 10-14%, the sun drying step is completed.

Sun exposure

3. Remove the outer shell

After the sun-drying process is over, the outer layer of the coffee seeds has dried and hardened. At this time, a shelling machine is used to remove the outer shell to complete the sun-drying process.

Shelling

advantage:

The sun-drying method does not require water except for the step of removing floating beans, and a bucket of water can be reused. It is low-cost, so it is widely used in areas where water resources are scarce and less wealthy.

shortcoming:

1. The sun-drying method requires the coffee beans to be placed outdoors and a large enough space for exposure, so there are often impurities such as dead branches and leaves mixed in.

2. Because it uses the energy of the sun, the degree of dryness of the coffee beans is difficult to control, resulting in the coffee fruits being "over-dried" and the internal coffee beans being damaged.

3. During the sun drying process, a lot of manpower is required to turn the fruits regularly. Since the pulp is not removed, it often becomes moldy and rotten.

Flavor:

Because the sun-drying method allows the coffee fruit to dry naturally, the coffee beans can mature naturally inside the fruit without being disturbed by the external environment. Therefore, the coffee beans processed by the sun-drying method will amplify their own flavor, have a rich body, strong flavor, and exude sweetness.

Water washing method

The Dutch invented the water-washing method in the 18th century. Since it often rains and the humidity is high in some countries, the sun-drying method cannot be implemented at all. Although the process is relatively cumbersome, it is currently the most widely used treatment method. The biggest difference from the sun-drying method is that fermentation is used to remove the pectin layer.

1. Remove floating beans (same as sun drying method)

Pour the coffee beans into a large tank. The underdeveloped and inferior beans will float to the surface, while the mature and plump beans will sink to the bottom. At this time, remove the floating beans on the water surface. This completes the step of removing the floating beans.

2. Remove the peel and pulp

The outer skin and pulp of the coffee fruit are removed through a pulping machine. (The pectin, inner skin and silver skin will remain)

Peeling

3. Fermentation

The purpose of this step is to use biological treatment methods to remove pectin. The coffee berries that have been processed by the pulp screener are placed in a fermentation tank for 16-36 hours, and the fermentation bacteria will dissolve the pectin.

Fermentation

4. Washing

After fermentation is completed and pectin is removed, the coffee beans are washed again because fermentation bacteria and impurities will remain on the coffee beans. In order to clean them thoroughly, this step consumes a lot of water.

Washing

5. Drying and removal of endocarp and silverskin

The coffee cherries are usually dried by machine (or sun-dried) to reduce the moisture content to 10-14%. Then the remaining inner peel and silver skin are removed by a shelling machine to complete the processing.

advantage:

1. All the processing procedures of the water-washing method are carried out indoors, so the impurities in the coffee beans can be reduced to a minimum and the quality can be maximized.

2. Since the pulp is removed at the beginning, there is no need to worry about mold as with the sun drying method.

3. The appearance is relatively complete and looks great.

shortcoming:

1. The procedure is complicated and tedious, so the cost is much higher than the sun drying method.

2. A large amount of clean water will be used. It takes 40-50 liters of clean water to obtain 1 kilogram of coffee beans. Therefore, it is rarely used in areas with water shortages.

Flavor:

Because of the fermentation process, coffee beans usually have a bright acidic and fruity aroma.

Semi-washing method

Improved treatment method to reduce water consumption of traditional water washing method

1. Screen out floating beans (same as water washing method)

2. Remove the pulp (same as washing method)

3. Machine to remove pectin

The original washing method used fermentation to remove pectin. The improved method is to use a pectin scraper (demucilager) to mechanically remove pectin.

4. Drying

Sun-dried or mechanically dried to a moisture content of 12%. The flavor of semi-washed beans is between sun-dried beans and washed beans, without the sourness of washed beans and the sweetness of sun-dried beans.

Honey Processing

What is the honey process? According to its English original meaning, its scientific name should be "pulp natural". Similar to the traditional wet process, it removes the thick skin of the coffee cherry and retains the mucilage underneath. Then it does not use fermentation to remove the mucilage layer, but instead allows it to be directly dried with this layer, and then directly removes the mucilage layer and the shell (parchment).

Honey Processing

Difficult honey processing method:

1. During the drying process, since the sticky pulp layer is still on the coffee beans, they must be turned over frequently in the first few days to prevent the coffee beans from sticking together. Therefore, it requires more manual labor than the general water washing method.

2. If it is not dried quickly, it will easily over-ferment

3. If the coffee beans are not turned enough, or the overall environment is too humid or too cold, or the sticky pulp layer is too thick, the coffee beans will easily mold. Therefore, some coffee farms use machines to control the thickness of the sticky pulp layer so that the coffee beans can be dried faster and the overall taste consistency will be better.

4. Compared with the wet treatment method, it requires a larger space and the drying time is longer.

Enhancement:

1. In the first 2-3 days of sun drying, it is best to do it under full-day monitoring. During this time, part of the pulp layer has been dried, and the coffee is less likely to have a bad fermentation taste.

2. During the drying process, you can use elevated sheds to provide better ventilation and less prone to mold.

3. If you dry coffee beans on a patio or terrace, the mucus from the pulp will seep into the patio, so you need to clean it thoroughly before drying the next batch of coffee beans.

advantage:

1. This is an improved method of sun drying. Since the pulp is removed at the beginning, there will be no problem of mold.

2. It does not require a large amount of clean water and has a low cost.

shortcoming:

The processing steps are arguably the most complex and labor-intensive of all methods.

Flavor characteristics

The advantage of honey processing is that it enhances the body and sweetness of coffee (hence it is also called honey process or miel process in English), relatively reduces its acidity, and the aroma will be more delicate. However, this is the taste when the honey processing is perfectly executed. If it is not executed well, it will taste bad and acetic, like the spicy aroma of onion or garlic. Even if it is executed quite well, it will still have a little mud taste, and the rest of the flavor will be less clean, and the miscellaneous flavor will be heavier than the general water-washing method. Therefore, overall, the risk of using honey processing is much higher than that of general wet processing.

Honey Processing

People often focus on the surface or the finished product, but ignore the big project behind it - coffee beans are not like fruits sold in supermarkets. It is impossible to sell them just after they are ripe. The processing method of raw coffee beans is often crucial to the quality of coffee. As a coffee lover, you must know something about it.