Explain the knowledge of coffee trees, picking and roasting of coffee beans

First, coffee trees

The coffee tree is an evergreen tree that can grow as high as a three-story building. However, generally planted coffee trees are trimmed to a height of less than two meters in order to facilitate harvesting. Coffee trees have white flowers, and the orchard has a faint jasmine fragrance when it blossoms. Like other fruit trees, coffee flowers will bear dark green oval fruit when they wither. Over time, the dark green fruit will gradually turn to yellow and then red, and the red fruit is the best condition for full ripening. Farmers are nicknamed "cherry" because their color is as red as a cherry. The coffee beans we are familiar with are the seeds that grow in the "cherry" fruit. The outer skin and useless flesh are removed from each fruit, and the two opposite seeds are wrapped inside.

There are four kinds of coffee trees in the world, of which only two are of real commercial value and have been planted in large quantities. One is the Elaraby species (Arabica), and the other is the Romasta species (Robusta). Different varieties of coffee beans have different tastes, but even the same varieties of coffee trees have their own unique flavor due to the influence of different soils and different climates.

2. Picking

Coffee trees begin to bear fruit about three to five years after sowing, and are harvested for the next 20 years from the beginning of fruiting. In order to facilitate harvesting, farmers prune coffee trees to no more than 150 centimeters, because they have to climb ladders to pick them, which is not only time-consuming, but also may hurt the trees by bending branches. Coffee trees need to be planted with some tall shade trees, which shade and dissipate heat during the day and keep warm at night, so you can often see the staggered arrangement of low shrubby coffee trees and banana or mango trees in the coffee garden.

Coffee fruit grows densely along each branch, and although it grows on the same branch, the ripening period of each fruit is different, some are still turquoise, some have slightly yellowish, some are yellowish red, some are fully ripe bright red, and some are dry dark brown. Because they are not ripe at the same time, coffee fruits must be picked manually. Red or yellowish red fruits must be manually selected before they can be picked, and green fruits must be skipped. Workers have to check the ripeness of the fruit at the same place every day before picking it. Coffee fruits from the same branch often take several weeks to pick back and forth again and again before the harvest is complete.

3. Baking

The main purpose of roasting coffee beans is to produce chemical changes in the internal structure of coffee beans by heating. More specifically, heating makes the bean water evaporate, the volume expands, the chloric acid in the bean is more uniform or low, the carbohydrate is coked, and the oil in the bean is released through the bean wall with fragrance. Baking must be uniform. If you only want to be fast and uneven, the beans may be beautiful on the outside but light on the inside, and have not yet begun to decompose. The deep roasting, medium roasting and shallow roasting of beans are decided and controlled by the coffee company; even there is a knack for cooling the beans before the baking is over, whether to spray or blow. If the temperature is not cooled quickly, the heat contained in the beans will make the beans darker and greasy, and the taste will become bitter.