Coffee Bean Processing

Refining process of Natural drying Coffee

Coffee cherry (coffee fruit) → selection processing → raw bean harvest → sun farm (sun exposure) → sheller (remove pulp, etc.) → electronic bean selector or wind bean selector (hand selection, screen, removal of defective beans, grading) → export

The purification process of washed Coffee

→ storage tank (removal of impurities-debris floating on the water and stones, rubbish, bad beans, etc.) → pulp removal machine (removal of pulp and debris that cannot float to the surface, such as stones, garbage, bad beans, etc.) → fermentation tank (removal of mucous membrane attached to the inner pericarp) → washing pool (washing Select lighter beans and hard beans) → dryer (machine drying) or sun field (sun exposure) → sheller (remove residual endocarp) → electronic bean selector or wind bean selector and specific gravity bean selector (hand selection, screen, defective beans, grading) → export

Semi-washing refining method

This is the discount between drying type and washing type. The method is to wash the harvested coffee fruit, remove the exocarp and pulp mechanically, then dry it with sunlight, and then end with mechanical drying. The difference between the water-washing refining method and the water-washing refining method is that the coffee fruit is not put into the fermentation pool in the process, and the quality is more stable than the drying refining method. This semi-washing process is used in the Cerrado region of Brazil.

As I mentioned earlier, most coffee-producing countries tend to adopt water-washing refining, while countries that use non-washing refining will use natural drying refining according to their own natural conditions, geographical location, production needs and other factors. Therefore, it is unfair and incorrect to regard the non-washing refining method as the transitional method of the washing refining method, and even think that the non-washing refining method is inferior to the washing refining method.

The reason why coffee beans with washing refining method can be highly recognized in Europe and the United States is that it has fewer impurities and defective beans, and the appearance of beans is clean and tidy. The general public is often misled that "washing is equal to delicious taste", but in fact, appearance is not equal to inner, washing and non-washing have their own advantages and disadvantages.

For example, the "mokamatali" in Yemen is small in appearance, and people who don't know how to do it will mistakenly think that it has four defective beans and impurities, but the unique aroma of this kind of coffee is irreplaceable by other coffee. It can be seen that there is no absolute relationship between the quality of coffee beans and the refining method.

The difference between dry and water-washed coffee

The difference in appearance

The water content of washed coffee is about 12% Mui 13%, and the water content of dry coffee is about 11% Mui 12%. The green of the former is darker in appearance, generally speaking, the raw beans with higher water content are more green or turquoise, and the coffee with less water content is brown or nearly white. Because the raw bean is refined by water washing, the silver skin (the cell coat attached to the surface of the raw bean) is removed, and the bean will show a special luster. While using the drying method of raw beans, after the beans are shelled, most of the silver skins remain on the surface of the beans.

In addition, as long as the raw coffee beans of the water washing refining method are not roasted deeply, there will still be a white silver skin on the central line after baking, while the silver skin of the drying refined coffee beans disappears after baking.

Thus, even after baking, the difference between the two is still clear. In addition, a small amount of silver skin residue will not have much effect on the taste of coffee, but if there is too much silver skin residue, the coffee will produce astringent taste.

Defective bean mixture

Brazilian coffee is mostly refined by non-washing. Except for some good products, most coffee beans are of poor quality, and there are a lot of "undercooked" and "overripe" coffee beans. Some of these defective beans are "unripe beans" and "fermented beans" are the biggest "headaches" for bakers. As a result, these beans are difficult to identify in the raw bean stage, and if they are not removed in hand-selected filtration, they can no longer be distinguished in appearance after baking.

There is another problem, that is, non-washing refined coffee beans, if the surrounding humidity is too high during the drying process, the coffee beans may be contaminated with the smell of soil (iodine smell), which can not be seen from the outside. You need to be careful about this.

Non-washing refined coffee beans in Yemen and Ethiopia are the same as in Brazil, with quite a lot of impurities and defective beans, so cleaning is more laborious than baking.

Water-washed coffee beans need to be washed many times before they become the final raw bean products. The branches of the stone and the coffee tree are not easy to mix, but they may be mixed with coffee beans contaminated with fermented flavor, so the disadvantage of water-washed beans is that the beans are easy to have the taste of fermentation. and fermented beans are almost the same as normal coffee beans in appearance. It is more difficult to get rid of these defective beans with fermented flavor than coffee beans that are not washed and refined.

Baking methods are different.

The high-quality coffee beans produced in Brazil using the natural drying method rarely have uneven coffee particle size and are quite suitable for baking because the natural drying method has removed the moisture in the center of the coffee beans. coffee beans with mild sour taste and less astringent taste can be baked. The most difficult part of baking is the control of "sour taste" and "astringent taste". Generally speaking, water-washed beans have a relatively short drying time, so the "sour taste" and "astringent taste" are relatively strong.

There are many ways to ease the "sour" and "astringent" taste. Leave the beans still for a while. It takes longer to bake new beans (New Crop) than to bake "dry-cleaned beans" (about 1% longer than dry-cleaned beans).

In this way, it seems that baking "water-washed beans" is more difficult, but if you bake "dry-cleaned beans" such as Yemen, Mocha, Manning, etc., you will find that there are other difficulties. "dry cleaning beans" in most cases, there will be uneven particle size and uneven degree of drying, so the focus is on how not to bake too much, depending on the baker's skill.