Why do coffee beans produce oil?

Coffee beans are seeds from the coffee plant that produce oils during the roasting process. This phenomenon can be traced back to the chemical composition of the coffee beans and changes during the roasting process.

First of all, coffee beans are rich in oils. These oils are mainly composed of fatty acids, including palmitic acid, linoleic acid and stearic acid. When coffee beans are heated, the oils begin to be released and gradually float to the surface of the beans to form a smooth and shiny lubricating substance.

Secondly, during the roasting process, many chemical reactions occur inside the coffee beans. As the temperature rises, nutrients such as vitamins, amino acids and carbohydrates begin to break down and react with oxygen in the air. These reactions lead to the formation of compounds that increase the number of complex and aroma and flavor formation.

At the same time, when dry or wet roasting is performed at high temperatures, moisture gradually evaporates from the inside. During this process, the structure of the coffee beans changes, causing the internal cells to rupture. When the cells rupture, the oils in them are released and gradually infiltrate the surface of the beans.

Finally, the oils formed during the roasting process help form a protective shell on the surface of the coffee beans. This shell prevents air from entering the beans and keeps them fresh. In addition, the oils can increase the aroma and flavor of the coffee and give it a special taste.

In short, the oil produced by coffee beans during the roasting process is due to the rich oil content in them and the influence of high temperature and chemical reactions. The quantity and quality of these oils play an important role in determining the final quality of coffee.