There are several ways to roast a coffee, here are types of the coffee roaster (เครื่องคั่วกาแฟ) that typically use for most people.
- Drum Roaster
This type is the most economical and most widely used form used with its simple design. consisting of a rotating cylindrical drum with heat being applied either directly to the drum or through the center through a conduit. The actual heat can come from the electric heating element or gas flames controlled with or without the use of a profile controller. In a drum roaster, heat is transferred thru conduction with the vast majority coming from convection. temperature measurements are reported usually by two gauges on the system. One measures the actual flame temperature and the other measures ambient bean temperature.
- Fluid Bed Roaster
It is a completely different system for roasting. The system which consists of a tall cylinder allows hot air to flow through a chamber that providing a homogeneous distribution of heat. It uses convection to deliver heat and has the distinct roast characteristic. Moreover, it is easy to clean up, less time during roasting and have roast uniformity.
Types of roast
There are different roasts in roasting coffee and this is also caused by bean selection how they are roasted and time spent roasting.
The first crack in the roaster is when you will produce a light roast. At this stage, the coffee’s natural acidity is preserved. A light body and mild cup characteristics can reveal a delicate flavor.
The second crack in the roaster is when a medium roast is produced. The coffee is fully developed before any oils appear on the surface of the beans. This extra roast time allows for more caramelization and then, improves the richness, body and mouth feel.
As a second crack can be heard from the roaster, a medium-dark profile is created. The coffees have reached full caramelization and richness, making its acidity even more subdued. And then bean would have the light oil sheen and the cup would have a deep coffee flavor.
After the second crack, the coffee will become fully covered in oil and no beans will carbonize. It has dominated a Deep, rich flavor, and heavy body. While the acidity of the coffee is very diminished.