The Coffee Roasting Process

Coffee Roasting

When it comes to coffee, roasting is a big deal and rightly so. By transforming the physical and chemical properties of the green coffee, roasting releases the sealed aroma and taste inside it, bringing out the flavor we crave. Once the right temperature is achieved, green coffee transforms into brown beans we see in commercial stores – the coffee we are familiar with. The once soft beans become hard and crunchy and with a bit more magic, become the elixir we all love.

How is roasting done?

After hulling, bags of green coffee beans are transported to roasting houses. But before they go through the actual roasting process, they are first screened to remove debris with the help of a hopper. Once sorted, the beans are then weighed and transferred to storage hoppers by a belt. From here, they are sent to the roaster and the roasting process finally begins.

The beginning of the roasting process is endothermic, meaning the beans are absorbing the heat. Roasters need to be mindful and sensitive to the changes taking place in the beans as they might need to adjust the temperature. When the heat reaches around 175 degrees Celsius, the beans begin to release the heat and the process becomes exothermic. Once the beans have been processed according to their roast level, they are transferred to an enclosure to be cooled quickly.

Several physical changes can be observed during the roasting process. But perhaps the most significant is the change is size –they become wider but lighter in weight due to the dehydration that takes place during the process. See, roasting releases water and other compounds, but the release of these chemicals result to the expansion of the cellulose making the beans wider.

It is important for a roaster to sense when the beans reach their required roast level. A matter of seconds will cause a big change to the taste and aroma of the beans. Hence, roasters need to have skills and expertise to come up with quality coffee.

Roast Level

The roast levels of coffee beans depend on the length they are roasted. There are four roast categories: light, medium, medium-dark, and dark. Coffee lovers have different preferences when it comes to roast level, and this is often because of geographical and cultural influences.

Light roast beans are brown and referred to as mildly-roasted. They tend to be dry to touch because the short roasting time does not permit the oil locked inside the beans to reach the surface. Some terms used to refer to light roast are Light City, Half City, and Cinnamon.

The medium roast will also result in brown non-oily beans, but the taste is stronger than the light roast. This type of beans is preferred in the United States; hence, it is often known as the American roast. Other names medium roast is referred to are City and Breakfast.

Medium dark roast beans have rich dark color and are slightly oily. They have a slight bittersweet taste. These beans are also called Full City by some roasters.

Dark roast beans are shiny, black, and oily. It has a definite bitter taste, but they are less acidic. The darker the beans are, the lesser their acidity level is. There are many names used to identify dark roast beans such as High, Continental, New Orleans, French, etc. Hence, to be sure, it is better to ask before you purchase.

Roasting with Phantom Series

After knowing how coffee beans are processed, it is good to choose your roaster to ensure a quality and desired level of roast will be achieved. Phantom Series coffee roasters offer an advanced system for controlling and monitoring the roasting process. With its PC-integrated technology, you can be sure to have Specialty Coffee easily. Along with the advanced technology comes its safety features too. You can be sure to minimise personal injuries and machine damages. When it comes to quality, Phantom Series uses high-caliber materials for a long-lasting efficiency. Contact us at +61-7-5529-0888 or send email to for more enquiries.