The relationship between coffee bean oil and roasting degree: a chemical variation of aroma

Coffee is one of the most popular drinks in the world, and its unique aroma and taste attract countless people. However, few people know that there are complex chemical variations hidden behind this delicious taste. The oil composition in coffee beans is closely related to the degree of roasting, and different degrees of roasting will bring completely different flavors.

First, let's take a look at the oil composition in coffee beans. Coffee beans contain a large amount of fatty acids and volatile compounds. Before being processed, these oils are wrapped inside the beans and are not released. When the coffee beans begin to be roasted, the temperature gradually rises, and at the appropriate temperature, the oils begin to be released from the inside and wet the surface.

The next step is the key step - the degree of roasting has an important impact on the flavor of coffee. Light roasting usually refers to heating the coffee beans to about 150-200 degrees Celsius. During this process, you only need to maintain a low temperature to allow the oil to begin to release. At this degree of roasting, the oil of the coffee beans is still relatively small, showing a bright acidity and floral aroma. Medium roasting (medium roasting) raises the temperature to 200-230 degrees Celsius, at which time the oil of the coffee beans begins to wet the surface more and produces a certain degree of acidity and sweetness. Dark roasting (dark roasting) further raises the temperature to above 230-250 degrees Celsius, at which time the oil of the coffee beans is completely released and partially burned, producing bitterness and a rich chocolate or roasted nut flavor.

In short, in the coffee making process, the oil content in coffee beans is closely related to the degree of roasting. Different degrees of roasting will bring completely different flavor characteristics: light roasting has bright sour and floral aromas; medium roasting has moderate acidity and sweetness; and dark roasting exudes rich bitterness, chocolate or nutty flavors. Therefore, when choosing to drink a cup of delicious coffee, we can choose the flavor that suits us according to our taste preferences and the degree of roasting of coffee beans.