Temperature and time length for coffee roasting process

Roasting is a process of exposing the green beans to a heating process that is  rapid enough to drive off the free and bound moistures and later the dry bean is heated above 180 °C to a moisture level of 2 to 2.5 %. The amount of time that the beans remain in the roaster determines the strength and flavor of the brewed coffee in the cup.

Actual contact roasting is no longer importance because heat transfer is uneven and the roasting times required are long (20-40 min).

In the contact convection roasting process (roasting time 6-15 min), efforts are made to increase the convection component as much as possible by suitable process management. Centrifugal roasters, revolving tube roasters, fluid-bed roasters etc. are used either batch or continuously.

In the new short-time roasting process (roasting time 2 to 5 min), the heating–up phase is significantly shortened by improved heat transfer.

What is important is to generate and control the correct temperature at the right moment then stop when the aroma has fully developed and the color of the coffee is homogenous throughout the whole bean.

To cater to different tastes, five different roasts have been developed. It is a rundown from very light to very dark.
*Cinnamon roast
*Regular roast
*City roast
*Dark roast
*French roast
Temperature and time length for coffee roasting process