Grading defective beans according to the proportion of sieve and defective beans is an important factor that destroys the flavor of the final coffee.

Boutique coffee (specialty coffee) is also called "specialty coffee" or "select coffee". It refers to coffee made from a small number of raw beans with excellent taste grown in an ideal geographical environment. Depending on the special soil and climatic conditions in which they grow, they have outstanding flavor. After strict selection and classification, this kind of coffee can be regarded as a selection of coffee beans because of its hard texture, rich taste and excellent flavor.

Grading according to the proportion of screen and defective beans

Defective beans are an important factor that destroys the flavor of the final coffee. Therefore, defective beans should also be removed in the last step of raw bean processing. Therefore, according to the proportion of defective beans, supplemented by the size of the screen is also used as a way of classification. Due to the rise of boutique coffee, coffee producing countries pay more and more attention to the quality of coffee, and the control of defective beans is the most important way, so basically using the proportion of defective beans as a grading method or auxiliary basis is becoming more and more common.

At present, the main representative countries that use defective bean proportion method are Jamaica, Brazil, Ethiopia and so on. Jamaica is based on the production area, altitude, screen, defective bean proportion comprehensive as the rating standard, defective bean proportion as an important basis. Jamaica strictly controls the proportion of defective beans, and the proportion of defective beans in all grades is no more than 4%.

Brazil is another special country. Brazil is the largest coffee producing country in the world. Because of its large output and many producing areas, the classification work is quite troublesome, and it is not suitable to adopt a single classification standard, so Brazil also uses a variety of classification methods at the same time. Defective bean proportion, sieve and cup evaluation tests are all used in the grading process of Brazilian coffee beans. Needless to say about the first two, the cup evaluation test is one of the characteristics of Brazilian coffee grading.

The so-called cup evaluation test is to evaluate the aroma and taste of raw coffee beans by soaking them in hot water (about 90 degrees) after baking. It is mainly divided into six grades: Strictly Soft extremely mild, Soft mild, Softish slightly mild, Hard difficult, Rio light iodine taste, Rioy strong iodine flavor. The first three grades can be called mild, with a balanced sweet and sour coffee and a mild taste. The latter three taste slightly worse, especially the latter two are the worst. The reason for the iodine smell is that the soil near Rio de Janeiro has a strong iodine smell, and the coffee is dropped on the ground during harvest and is contaminated with the peculiar smell of the adsorbed soil.

The above three are the popular coffee grading methods, but not all of them. For example, Ethiopia will take the handling of raw coffee beans as one of the grading criteria. In addition, there is a more and more widely used COE rating system. As coffee producing countries pay more and more attention to coffee quality and the enthusiasm of producers, the classification of raw coffee beans is not limited to the above three main ways. Only with more careful planting can we produce higher quality coffee and get a high rating in the grade evaluation, so the subdivision and strict control of coffee rating is undoubtedly a good thing for the improvement of coffee quality.