How to select coffee beans by hand

Hand selection: is the step of removing impurities and bad beans attached to delicious coffee beans. Coffee beans are often mixed with foreign bodies, such as stones, sawdust, pieces of metal, grains of soil, fruit of trees, and sometimes coins and glass.

In coffee production areas, specific gravity bean selector (using wind power to classify according to particle size and weight) or electronic bean selector (removing defective beans according to color) will be used to prevent impurities and defective beans from mixing, but it is only natural that they cannot be prevented. It still has to be chosen by human hands.

In particular, unripe beans are difficult to remove by machine and must be removed by hand. And these unripe beans will have a very bad effect on the taste of coffee. Defective beans in addition to unripe beans, there are dead beans, worm-eaten beans, black beans, moldy beans, shell beans, fermented beans, broken beans, shell beans, cocoa and so on.

Hand selection is carried out once in the raw bean stage, and again after baking, which means once before and after baking. The proportion of defective beans is surprisingly high, good coffee beans generally contain about 20%, and mocha with low precision system is more than 40%. That is to say, only about 60 to 70% of the coffee beans can be used after roasting. In other words, there will be 30 to 40 grams of failed beans in 100 grams of raw beans, which is quite wasteful. To reduce the roasting failure rate, you must buy high-precision and high-quality coffee beans as much as possible; if you are still afraid of roasting failure, the steps to remove defective beans should not be lazy. Defective beans are fatal to the taste of coffee.

When the ripe and red coffee fruit is picked by hand, the mixing rate of defective beans should be much lower, but in fact, it will be picked along with the cyan immature fruit during the harvest, and sometimes, even the branches will be broken off in pursuit of harvest efficiency. The water-washed coffee because the refining process must be washed many times, so it is more difficult to mix with stones, glass sheets and other impurities, but if the non-washing natural drying coffee, the degree of impurity mixing is quite high.

When roasting coffee mixed with too many defective beans, the finished coffee will be mottled in color. Compared with normal beans, defective beans oxidize very quickly and appear white after baking. Cheap coffee beans are often sold in stores such as supermarkets or coffee shops, and when you open those packages, you can find that there are quite a lot of unevenly roasted beans, all as a result of omitting the manual steps of direct baking.

The quickest way to understand the importance of hand-selected steps is to bake coffee liquid extracted with defective beans. After drinking it, you will find that your tongue will remain paralyzed for hours. It can be proved that hand selection is an indispensable and important step in making delicious coffee. I think it is a pity that people often regard hand selection as monotonous, boring and meaningless behavior. But I hope you understand that the taste damage caused by defective beans cannot be hidden no matter how clever the baking technique is. In order for the baking to proceed smoothly, it is important to select the steps by hand in advance.