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Do I need to pick defective beans for Italian hand-brewed single-piece coffee? What is the difference between the mouldy beans, black beans, insect eaten beans, Quake beans in coffee?

Published: 2026-03-31 Author:

Last Updated: 2026/03/31, "Is it necessary to pick beans before making coffee? "This is a question that a guest friend asked Qianjie when buying beans yesterday. On the Internet, we can often see some bloggers sharing this kind of related content. The general meaning of these content is that picking beans before making coffee can make the coffee better.

"Is it necessary to pick beans before making coffee? "This is a question that a guest friend asked Qianjie when buying beans yesterday. On the Internet, we can often see bloggers sharing this kind of related content. The general meaning of these content is that picking beans before making coffee can make the brewed coffee taste better. Why? Because we need to pick out those defective coffee beans that will affect coffee and have negative flavors!

The so-called defective coffee beans refer to those coffee beans with defects. This defect does not only refer to damage from appearance, but also refers to coffee beans that have been contaminated and qualitatively transformed, which will endanger human health. These defective beans can be divided into different degrees, but without exception, they will have a very unpleasant taste. If it is a severely defective bean, only a small amount can directly affect the taste of an entire serving of coffee beans.

The more common defective beans that can affect the taste of coffee are mainly these: moldy beans, most-eaten beans, and black beans. Moldy beans refer to coffee beans that are moldy due to improper operation during processing or storage. These coffee beans will have negative smells such as mouldy and sour odors. And they are also very easy to distinguish, and some part or all of their bodies will show abnormal signs of dispirited and discolored colors. However, the characteristics of the beans will be relatively less obvious after they are baked and mature.

Most-eaten beans refer to those coffee beans that have been eaten by pests during growth and development. These coffee beans will also have some negative flavors such as mildew smell and medicine smell, because most-eaten coffee beans are very easy to produce mildew. Their characteristics are also very obvious. There are several small holes bitten by insects on the smooth surface of the beans. Even after the beans are baked and mature, these small holes are still clearly visible.

Black beans, as the name suggests, refer to beans that have been infected with a disease during development, or coffee cherries that fall to the ground and become contaminated with bacteria, or coffee beans that are overfermented during processing that are dark throughout the body or body. These beans produce that negative flavor similar to mildew.

Another special kind is Quake beans. Quake beans refer to those coffee beans that are not fully developed. These coffee beans cannot develop rich aroma during processing and roasting due to insufficient sugar. In the raw state, because the color is close, it is difficult to distinguish it from the normally developing coffee beans. However, due to their lack of sugar, the reaction during the roasting process will be relatively weak, so the color after roasting will be much lighter than that of normal coffee beans, making them easy to identify.

The above are some defective beans that will affect the taste of coffee. If you want to pick beans before making coffee, then you should recognize them. Of course, in addition to this, there are also some impurities such as small stones that do not affect the taste but will affect the life of the appliance. They also need to be picked out. But in fact, as long as the business you choose is reliable enough, then picking beans can actually be "exempted". For example, Qianjie is very reliable (just kidding, but not all...). Because reliable merchants will screen coffee beans multiple times before and after roasting beans. For example, Qianjie will screen coffee beans multiple times manually and machine before and after roasting coffee beans. The purpose is also very simple, to avoid flaws affecting the overall quality. This is responsible to the guests and to yourself.

The following is a 15-g portion of coffee beans randomly selected and weighed by Front Street-Front Street Panama Poquet Rose Summer. It can be seen that this bean does not contain any of the above-mentioned defective beans. This is the result obtained after multiple screenings.

Since there are no flaws, the taste is naturally the excellent flavor of the coffee beans themselves. We can taste the elegant white flower fragrance, rich citrus fruit flavor, and the finish of green tea and honey. The overall taste is clean and solid, without any miscellaneous flavors. But in general, whether you need to pick beans or not before making coffee depends mainly on your choice. If people are really worried that defective beans will affect the flavor of coffee, then it's okay to spend 1 minute picking beans before brewing ~

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FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou China, selling freshly roasted beans from its own farm in Yunnan as well as dozens of carefully selected single-origin beans from around the world for both pour-over and espresso. The products deliver consistently excellent quality and great value, with shipping within 24 hours. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers, and the beans are now available online at the Tmall 。