Basic knowledge of coffee selection methods and matters needing attention of raw coffee beans

Raw beans before selection

Fruit doesn't taste different because of its size. What about coffee beans? What happens if coffee beans, regardless of size, maturity or unmaturity, harvested from the same tree, are all roasted in the same pot?

Thick beans are baked together with thin beans. Thick beans have poor heat transmission and the center (the part of the beans where water has not been removed) will occur in the "core" state that cannot be baked. Spaghetti is cooked until it has a "core" in order to have a moderate taste; but the "core" state is allowed only in the world of pasta, not in the world of coffee.

The "cored" coffee cannot be seen on the outside, only the beautiful surface of the roasted beans can be seen, but it is clear when it is cut open. The beans are divided into baked and unbaked parts. The coffee extract from cored coffee will have a strong taste that will choke your throat.

Anyway, when choosing green coffee beans, the beans with uniform shape, thickness, size, color, center line extension, etc. are the best. In short, an average bean is a good bean. Unfortunately, such beans are extremely rare.

Some people often ask, what do G1 and G2 mean, AA and AB mean, why do some G2 drink better than G1? These are all grading methods, and they are official grading methods, based on size, defect rate and altitude. However, there is one thing that everyone has not noticed, which is not graded according to taste. According to size, coffee beans with large particles are evaluated higher in the same production place. It is also said that the grading of the sieve size (coffee bean size) has nothing to do with French taste. The Nordic countries, which are now coffee advanced countries, purchase the most advanced coffee beans from Brazil and other places, mainly buying small particles of beans with sieve size 13-16. They avoid buying expensive, larger beans in favor of cheaper, smaller ones, perhaps because they value quality over reputation.

But strictly speaking, large coffee beans have better flavor. Actually, the size beans harvested from the same coffee tree were roasted and extracted. After cup testing, the taste difference could be obviously compared. Beans that are bigger and grow smoothly taste better.

When it comes to large-grain coffee beans, there are often high-quality beans twice as large as ordinary beans, such as marago gipe (large-grain beans above No.19 sieve, also known as elephant beans), which will cause uneven roasting, so it is recommended to pick them out by hand in advance: this is not to pick out defective beans, but to gather large-grain beans together and roast them separately.

In baking, consistency in bean size is more important than size and taste. Beans of different sizes should be kept separate and should not be baked together. Otherwise, it will inevitably lead to uneven baking results.

The left side contains less water and the right side is greener, indicating more water.

Similarly, the color of the beans should be consistent. The color of raw beans is cyan, brown and other colors. The color of beans indicates the water content, so the color of beans is consistent and easier to bake. Generally speaking, cyan and green represent more moisture, while brown and almost white represent less moisture.

The beans on the left are thin and the beans on the right are thick.

Then there is the shape of beans, to choose the meat thickness is better. Even if the beans are large in grain size, thin ones tend to taste thin. rich and rich in flavor and depth, usually only the fleshy coffee beans produced in the highlands. Kenya, Colombia, Tanzania and other Arabica seed washed coffee beans are classified as "Colombia fresh bright coffee" by the New York market; the meat is thick and the moisture content is high, so it is difficult to transfer heat in the center during roasting, but through excessive roasting, it can lead to rich and varied flavors.

The last thing to mention is the central line (the longitudinal groove in the center of the coffee bean). Beans with a clear and well-defined center line are good quality. In addition, the silver skin covering its surface is preferably silver as shown in the literal. Silver skin appears tea brown, in addition to good management of natural drying method beans, mostly defective products.

What is Hand Selection?

Hand selection: It is a step to remove impurities and bad beans attached to delicious coffee beans. Coffee beans are often mixed with foreign matter, such as stones, wood chips, metal pieces, soil particles, tree fruits, etc., and sometimes coins and glass pieces.

At coffee production sites, specific gravity bean sorters (which use wind to classify beans according to particle size and weight) or electronic bean sorters (which remove defective beans according to color) are used to prevent impurities and defective beans from mixing, but it is natural to prevent them, and it is still necessary to rely on human hands to select them.

Unripe beans, in particular, are difficult to remove by machine and must be removed by hand. And these unripe beans can have a very bad effect on the taste of coffee. In addition to immature beans, defective beans also include dead beans, moth-eaten beans, black beans, moldy beans, shell beans, fermented beans, cracked beans, shelled beans, cocoa and so on.

Hand selection is done once during the green bean stage and again after baking, meaning it is done once before and after baking. The proportion of defective beans is surprisingly high, good coffee beans generally contain about 20%, and low purity mocha is even higher than 40%. That is to say, after roasting, only about sixty or seventy percent of the coffee beans can be used. In other words, there will be thirty to forty grams of failed products in 100 grams of raw beans, which is quite wasteful. To reduce roasting failure, you must buy high-quality coffee beans as much as possible; if you are still afraid of roasting failure, you must not be lazy in removing defective beans. Defective beans are the bane of coffee taste.

When harvesting ripe, reddened coffee fruits by hand, the percentage of defective beans mixed in should be much lower, but in fact, green immature fruits are also picked at harvest time. Sometimes, in order to pursue harvesting efficiency, even branches are broken down. The washing type coffee because the refining process must be washed many times, so it is difficult to mix stones, glass pieces and other impurities, but if the non-washing type of natural drying method coffee, the degree of impurity mixing is quite high.

Roasting coffee mixed with too many defective beans, coffee products will appear color mottled situation. Defective beans oxidize at an unusually rapid rate compared to normal beans, and some turn white after baking. Cheap coffee beans are often sold in supermarkets or coffee shops, and when you open those packages, you can find that there are quite a lot of beans mixed in, which are the result of omitting the manual selection step and roasting directly.

The quickest way to understand the importance of the hand-picked step is to cup the coffee extract roasted with defective beans. After drinking it, you'll notice that your tongue stays numb for hours. Therefore, hand selection is an indispensable step in making delicious coffee. I think it is a pity that people tend to dismiss hand selection as monotonous, boring and meaningless. But I want you to understand that the flavor damage caused by defective beans cannot be hidden by any good baking technique. For baking to proceed smoothly, it is important to select the steps manually beforehand.