How is commercial coffee roasted?

Preheating: Before the beans hit the roaster, the machine is preheated to ensure a consistent starting temperature.

Drying Phase: This initial stage, lasting about 6 to 8 minutes, sees the beans lose moisture. They change from green to yellow, expand slightly, and become lighter in weight but less dense. The temperature typically ranges from 320°F to 350°F (160°C to 175°C).

Maillard Reaction: As the temperature rises (around 350°F to 400°F or 175°C to 205°C), the Maillard Reaction kicks in, creating new flavor compounds. The beans start to brown, and their density increases.

First Crack: A critical point in roasting, the beans expand and emit a cracking sound due to the pressure building inside. The color deepens, approaching a light roast, typically around 380°F to 420°F (195°C to 215°C).

Development Phase: After the first crack, the beans continue to roast, deepening in flavor. The roaster adjusts time and temperature based on the desired outcome, usually around 430°F to 450°F (220°C to 230°C) for a medium roast.

Second Crack: For darker roasts, the beans experience a second crack, where they become even darker and oilier. This stage occurs at temperatures around 465°F to 485°F (240°C to 250°C).

Cooling: Post-roasting, beans are quickly cooled to halt the roasting process. This can be done with air or water, with air cooling using a blast of cold air and water cooling using a mist to rapidly drop the bean temperature.

Yetinhon High-Performance Commercial Coffee Roaster, available in gas or electric, features independent roasting and cooling functions that reduce cycle times to just 3-5 minutes. This rapid cooling technique preserves aroma and flavor, ensuring consistently superior roast quality.

Roasters come in two main types: drum roasters and fluid bed roasters. Drum roasters use both conduction and convection, while fluid bed roasters rely solely on convection, providing a more even and faster roast that minimizes the risk of burning.