We have been explaining the roasting process and its different stages in our previous articles and now we have an additional point regarding the kind of tools that is used for it: the coffee roasters.
As you may be aware, coffee will tend to be roasted close to where it will be finally consumed, as the green coffee beans are more stable than roasted ones, which is why coffee is usually best used within one month from the moment it’s roasted.
We are going to have a look now at the different types of roasters that are mainly used:
- Drum roasters: probably the most popular and most used one, invented around the 20th century, they are especially popular amongst craft roasters thanks to their capability to roast at a slower speed.
They consist in a metal drum rotating above a flame, moving the coffee beans constantly to allow them to be roasted evenly.
As the flames can be controlled, so can the heat that is applied on the drum and the flow of air that goes through it. All those factors are the ones that will then dictate the heat that is transferred to the beans.
- Fluid-bed roasters: Created in the 1970s, the fluid-bed roasters tumble and apply heat to the beans thanks to pumping jets of hot air through the whole machine. It allows to roast significantly faster than the drum roasters thanks to a quicker hot air circulation.
- Tangential Roasters: Quite similar to drum roasters, they present an internal shovel that mixes the coffee in an even manner allowing big batches to be roasted effectively. The capacity is similar to the biggest drum roasters, but it allows to have a faster roasting process.
- Centrifugal roasters: Those tools allow very big batches of coffee to be roasted in a very quick manner. Place inside a very large inverted cone, the coffee is spinning and gets drawn up to the cone’s walls. The beans then return to the centre of the cone and the process starts all over again.
The main advantage of this method of roasting is the speed, that can allow batches to take only up to 90 seconds to be roasted.