If the inlet or exhaust air temperature exceeds the bean temperature, what is likely to happen to the bean?

When the inlet or exhaust air temperature exceeds the bean temperature, heat transfer occurs from the air to the coffee beans, causing the beans' temperature to rise. This is an essential process in coffee roasting, as it allows for the development of flavors and aromas within the beans.

Additionally, if the air temperature is significantly higher than the temperature of the beans, it indicates a strong incoming heat source, which accelerates the roasting process. As a result, the beans will absorb this additional heat, leading to an increase in their temperature. This allows for the physical and chemical reactions, such as caramelization and Maillard reactions, which are critical to developing the desired characteristics in the final roasted coffee.

Understanding this phenomenon is crucial for achieving the desired roast profile. If the air temperature is managed correctly, it can enhance flavor development, but if not controlled, it can lead to over-roasting or burning, which underlines the importance of monitoring temperatures accurately during the roasting process.