Understand the whole picture of coffee in one picture

Exocarp

The exocarp is composed of 1 to 2 layers of cells. Its structural characteristics are similar to those of biological epidermis, with cuticles and stomata. When the coffee fruit is immature, the parenchyma cells of the outer pericarp contain many chloroplasts, which turn into chromoplasts when mature. Depending on the degree of ripeness, the outer skin of the coffee cherries slowly changes from green to red.

Pulp

From a biological point of view, the pulp of coffee is part of the peel and is developed from the ovary wall of the plant. Coffee pulp contains sugar and acid, with a melon-like sweetness and clear and pleasant acidity.

Pectin layer

The coffee pectin layer is a heteropolysaccharide between the pulp and the endocarp (parchment), which is slimy to the touch and difficult to dissolve in water. The pectin part is the part with the highest sugar content in the coffee fruit and is an important component during coffee processing and fermentation. For example, the more pectin retained during honey processing, the more obvious the fermentation and sweetness of the coffee beans will be.

Parchment/Silverskin

Parchment is composed of thin-walled cells that protect the coffee beans. Silverskin is a very thin film between the parchment layer and the coffee bean. It is a cytoplasmic membrane. The core (coffee bean) is the seed of the coffee tree. Generally speaking, one coffee fruit contains two coffee beans. Because the two coffee beans are flat, they are called flat beans/lentils. In some cases, one of the coffee beans is underdeveloped during the growth process, leaving the other coffee bean with enough space to grow and taking on an oval shape, so it is called a round bean/bead.

Germ

The split in the middle of the coffee bean is the germ part, which will develop into leaves and stems after breaking through the skin of the coffee seed.