Coffee bean anatomy: exploring its composition and properties

The appearance and composition of coffee beans

Coffee beans are a very common food in our daily life. They have unique shapes and colors. Generally speaking, coffee beans are oval or flat, and usually have two relatively smooth sides. These sides are called the back and the belly. The back is the convex side, and the belly is the concave side.

When we look closely at coffee beans, we can see that they are covered with a thin layer of skin. This thin layer is called the pericarp and is removed during processing. Under the pericarp is another important component - the mucilage layer. The mucilage layer surrounds the kernel (what we usually call "coffee bean") and plays a key role in protecting the kernel from the outside environment.

Coffee bean kernel: main components and characteristics

When we open a coffee bean, we can see that its kernel is dark brown or light brown and has a certain luster. This is due to the rich oil in the kernel. The kernel of a coffee bean is mainly composed of two parts: the endosperm and the skin.

The endosperm is the largest part of the coffee bean, occupying most of the space in the kernel. It mainly contains caffeine, sugars, proteins and other substances, which give the coffee bean its unique aroma and taste.

The skin is a thin film covering the surface of the endosperm, which plays a protective and supporting role. The skin is rich in cellulose and other ingredients, which makes the coffee beans have a certain toughness.

Effects of roasting on coffee bean composition and properties

Roasting is a very important and indispensable step in the coffee making process. By controlling the roasting time and temperature, the coffee beans can be processed and their composition and characteristics can be adjusted.

First, roasting at high temperatures causes the mucilage layer to dry out and crack, exposing the core, which results in a more intense flavor because the oils and aromas released during roasting are more exposed to air.

Secondly, roasting also causes chemical changes in the endosperm inside the coffee beans. As the temperature rises, the sugars in the endosperm begin to break down and produce a series of complex compounds. These compounds give the coffee beans different degrees of sourness, bitterness and sweetness.

The differences between different types of coffee beans

While all coffee beans have similar makeup and characteristics, there are still some subtle differences between different types.

The first is the difference in varieties. Currently, the two main varieties on the market are Arabica and Robusta. Arabica is generally considered to have higher quality and lower acidity, while Robusta has higher acidity and a bitter taste.

The second is the influence of environmental factors such as soil and climate in the place of origin. Coffee beans from different regions are affected by different natural conditions during their growth, thus forming unique flavors and aromas.

In addition, coffee beans may also undergo different treatment methods during the later processing, such as fermentation, washing, etc. These treatment methods will also have a certain impact on the final product.

Conclusion

By exploring the composition and characteristics of coffee beans, we can better understand this food that is ubiquitous in our daily lives. Whether it is the unique shape and color in appearance, the subtle relationship between the endosperm and the outer skin, or the chemical changes that occur during the roasting process, they all provide us with a window to gain a deeper understanding of the world of coffee.

At the same time, differences in varieties, origins and processing methods make each cup of coffee have its own unique and delicious flavor. Therefore, when enjoying a cup of fragrant and delicious coffee, please remember to sigh that it contains infinite charm and is worth exploring.