There are two main methods of roasting; fluid-bed or drum roasting. The majority of roasting occurs with large drum roasters. I use a 12lb fluid-bed roaster.
Imagine a fluid bed roaster as a hot air popcorn maker. Beans are suspended in a cylinder above heating elements. Air is drawn over the elements and through the beans causing the beans to move in a fluid motion. The person roasting has infinite control over temperature and roast speed, resulting in distinct roast characteristics and uniformity.
In a drum roaster green beans are put in a rotating cylinder and heat is applied, either underneath or through a conduit in the centre. Â
Heat transfer is much faster in a fluid-bed roaster, a critical factor when driving moisture out of the bean (time to first crack).Â
