Coffee Beans

The first step in roasting coffee beans is to turn them green. This is done by placing them in batches into a roaster at a temperature of 160 degrees Celsius. The beans are then allowed to sit for six to eight minutes until the moisture content reaches the level of seventy-five percent. During this time, the beans begin to expand and swell as a result of the intense heat. At this point, they are no longer green but instead turn yellow.

Once soaked in water, coffee beans are then steamed. This steam allows the caffeine in the coffee beans to escape and is responsible for a duller, less aromatic coffee bean. During this process, the beans are carefully regulated so that they reach a certain point in the roasting process, which increases their porosity, making them less dense and more soluble. Because the oils in coffee beans migrate during roasting, they are less oily.

The process of roasted coffee beans is not difficult to understand. The first step is to look at the process from the outside. A roasting oven produces a high temperature inside the bean. This process causes the cell walls to change, resulting in a hollow, gassy center. As the temperature rises, the water starts to vaporize, and the beans lose mass. The second step is to measure the amount of moisture loss to ensure that the coffee is as delicious as possible.

How Coffee Beans Are Roasted

Once the beans are cooled, the second step is the drying process. As the beans dry, they release carbon dioxide that can last for days or even weeks. This is called the degassing phase. The first two days after roasting, the beans rapidly release carbon dioxide while the second days release slowly. After the second day, the beans begin to release a more complex flavor. This process is known as the city roast.

After the drying stage, the beans undergo the browning stage. This process triggers the Maillard reaction and releases hundreds of aroma and color compounds. During this stage, the coffee beans start to pop, or develop a crack. This is the development stage. It will take about three to five days to reach the full flavour. Once it has reached this point, the beans will begin to turn dark and will produce a smell and colour that are unique to the bean.

In the early roasting phase, the coffee beans are popped open. The heat from the roasting process works from the outside in, releasing moisture and breaking down the bean. This process is known as the “first crack” and occurs when the first crack is broken, while the second crack occurs when the coffee beans are already fully broken down. This is when the coffee begins to lose its green and turn brown.