Little history lesson for you here:
The coffee cherries are oval-shaped. After the coffee flower falls off, the fruit is only the size of a match head. After 6 to 8 months of growth, it will slowly grow larger. Depending on the cultivation environment and variety, the size of the coffee cherries at harvest is also different. If it is Arabica, the fruit will be 1.5~2cm in size, and the cross-sectional diameter will be 1~1.5cm; the fruit of Robaska is slightly smaller than that of Arabica.
When the fruit is ripe, the pulp becomes very soft. The flesh of coffee cherries is not thick, but the taste is relatively sweet. During the harvest season, you can often see the children who come to help put the flesh into their mouths to eat.
After peeling off the pulp, you will see a thin layer of skin on the seeds. This is the endocarp of coffee beans, and the seeds that wrap the inner flesh are also called "parchment coffee beans". There is also a sticky substance attached to the surface of the endocarp. This sticky substance is called pectin. To take out the coffee beans, you must remove the pulp, pectin, and endocarp.
The coffee beans are basically two growing together. So the coffee beans will be flat on one side. This kind of coffee beans with one side is called "flat beans".
Some coffee cherries only grow one seed (5%-20% of the total), which is caused by fertilization or environmental factors, which causes serious deterioration of the seed growth on one side, which looks round ( In this case, the seeds on the other side will not be produced), this kind of round coffee beans, we call it "round beans".
In the coffee bean sorting process (the process of distinguishing the size and picking out the coffee beans of poor quality), the "round beans" should be selected from the "flat beans". Because the number of coffee round beans is scarce, they should be sold separately from the usual coffee flat beans. Coffee beans in Brazil, Blue Mountains and other places are very famous, and they sell at a higher price than flat beans. But for farmers, there should be two coffee beans in a fruit, but only one grows out. This will greatly affect the output of coffee beans, so this is not a pleasant thing.