In this blog post, we will look at the importance of the roasting process in determining the taste and aroma of coffee, the changes that occur at each stage, and the differences in flavor depending on the roasting method.
In modern society, it is easy to see many people enjoying coffee. Coffee has become a daily favorite food due to the westernization of eating habits and an increase in preferences. However, many people like coffee but are not familiar with its various flavors. If you are interested in what flavors and aromas appear during the process of making coffee, you will be able to enjoy coffee more deliciously according to your personal preferences. In this article, we will focus on roasting, which is one of the many factors that affect the flavor of coffee. First, we will discuss the necessity of roasting, then the types of machines used for roasting, and finally the process and steps of roasting.
The roasting process of coffee is often described as magic, art, and science. This is because coffee beans themselves have no taste or aroma. The unique taste and aroma we feel when we drink coffee are not the characteristics of the beans themselves. Only after the roasting process, in which the beans are roasted and made into coffee beans, does the taste and aroma of coffee emerge. Therefore, it is very important to understand the roasting process in order to make the coffee you want.
There are three main types of machines used for roasting. First, direct fire roasting is a method in which coffee beans are roasted by being directly exposed to fire. This method has the advantage of being able to finish roasting in a short amount of time, but care must be taken as the coffee beans can easily burn. Second, semi-hot air roasting is a method in which the coffee beans are heated by fire and roasted by heat conduction. Compared to direct-fire roasting, the heat is evenly distributed, making it easier to determine the progress of the roasting. Finally, the hot-air roasting method uses high-temperature hot air to roast coffee beans in the air, and has the advantage of being able to achieve the most uniform roasting of the three methods.
The choice of roasting machine is important, but the most important thing is to understand the roasting process. The roasting process can be divided into the following stages: input, yellow, first crack, second crack, and cooling. When coffee beans are input, the beans are heated at 260°C to 500°C. When the internal temperature of the coffee beans reaches 100°C to 130°C, the moisture evaporates and the color turns yellow, entering the yellow stage. At 140°C, the carbohydrates, proteins, fats, and organic acids in the coffee beans are broken down and carbon dioxide is released. At 150°C, the coffee beans expand through an endothermic process, which is called the primary crack stage. The secondary crack is the stage in which the coffee beans undergo pyrolysis at 200°C and an exothermic reaction occurs. When the internal temperature of the coffee beans reaches 220°C to 230°C, the roasting process must be stopped and the beans must be cooled quickly to prevent carbonization. Cooling is done by circulating cold air or spraying water.
The roasting process can be divided into detailed stages according to the intensity. This varies slightly from country to country or region, but generally falls into eight categories: light, cinnamon, medium, high, city, full city, French, and Italian. Light and cinnamon fall into the light roasting category, medium and city fall into the medium roasting category, and full city and Italian fall into the strong roasting category. The stronger the intensity, the longer the roasting time.
In general, short roasts produce a strong sour taste, while long roasts produce a strong bitter taste. In light and cinnamon roasts, which are mild roasts, the sour taste is strong and there is almost no coffee aroma. In medium roasts, a soft sour taste and a unique aroma are produced. The high-roasting stage is between the end of the first crack and the beginning of the second crack, and it is at this stage that bitterness begins to intensify and harmonizes with sourness. During the city-roasting stage, sweetness reaches its peak, and bitterness becomes stronger than sourness. In the full-city stage, sourness almost disappears and bitterness becomes dominant, and the coffee’s unique aroma is very strong. During the French and Italian roasting stages, the taste of burnt sugar begins to develop due to the carbonized starch and sugar. The degree of roasting can be determined not only by changes in taste and aroma, but also by the color of the coffee beans. The green beans that were initially green gradually turn yellow and light brown, and then gradually turn dark brown, and finally turn black during the Italian roasting stage.
We have now looked at coffee roasting. Coffee beans have no taste or aroma, and it is only through the roasting process that the coffee develops its unique flavor. Roasting is an essential step in the production of a cup of coffee. Coffee has a much wider variety of flavors and aromas than you might think, and roasting is one of the important factors that determine these flavors. In addition to roasting, the type of coffee beans, the degree of grinding, the brewing method, and the blending process all affect the flavor of the coffee. By taking these factors into account, you can harmonize the ingredients of the coffee beans to create a delicious cup of coffee. If you consider these factors when drinking coffee in the future and focus on the taste and aroma, you will be able to enjoy coffee more fully.
