The classification of coffee beans. Classification of raw beans.

Plant classification

Coffee tree belongs to the evergreen tree of Rubiaceae. Since ancient times, most of the plants of Rubiaceae are plants with special effects, such as quinine tree, which is regarded as a specific drug for malaria, and Dugan, which is used to treat amoeba dysentery. Coffee is defined as the most unique alkaloid drinking flora.

The fruit of coffee is formed by the outer skin, pulp, endocarp, silver skin, and the seeds wrapped in the innermost layers (coffee beans). The seeds are located in the center of the fruit, and the parts outside the seeds are of little use. Generally speaking, there are two pairs of seeds in the fruit, but occasionally there is only one seed in the fruit, which is called fruit bean. In order to show symmetry, we call the fruit with two pairs of seeds as female beans. There are at least 40 "species" of the genus Coffee, among which the more practical cultivated species are three original species: plateau cultivation, lowland cultivation, and minimum cultivation.

Generally speaking, after two to three years of sowing, coffee trees can grow to a height of about five to ten meters, but in case coffee beans lose their aroma, taste bad, and are easy to harvest, farmers often repair them to about 1.5 to two meters. The change begins to bear fruit three to five years after sowing. The harvest period will be 20 years after the fifth year.

Coffee tree evergreen leaves, the leaf tip is more pointed, and is two opposite groups. The surface of the leaf is dark green, the back is light green, and the blooming flower is pure white. There are five stamens and one pistil in the flower, and the petals are usually five, but some have six or even eight petals. The flowers will give off a jasmine-like fragrance, but the flowers will wither in about three or four days. At first, the fruit is the same dark green as the leaf surface, but as it becomes more and more mature, it will turn yellow, then red, and finally crimson.

The circular zone between the Tropic of Cancer and the Tropic of Cancer is called Coffee Zone or Coffee Belt. Because the area is rich in rich organic matter and volcanic ash soil, the average temperature is about 20 degrees, the average annual rainfall is between 1000 and 2000mm, and there is no large temperature difference during the year, so it has become an ideal place for coffee production. Growing coffee should be strictly protected against cold, hot and dry wind and defrosting.