What do coffee roasters mean?

Coffee roasters can be coffee roasting machines or roasted coffee makers. In this article, I would like to talk about coffee roasters as machines. Roasting coffee is a very first and important step in making coffee. We roast green coffee beans into roasted beans, then grind them into ground and finally brew it into coffee liquid that we drink. Some people now love to do the whole process by their own, at their home. And that’s reason why we have coffee roasters. 

A coffee roaster comes in two different types of home-roasting machines: fluid-air bed and drum. Fluid-air bed machines roast the beans by floating them on a “bed” of hot air. Drum machines roast by heating a rotating chamber. The beans are roasted by the surrounding temperature inside the chamber and link to the hot surface of the drum. In general, fluid-air bed coffee roasters will roast faster and hotter than drum coffee roasters. Home-use fluid-air bed roasters, however, also have less capacity per roast than a drum roaster because of its limitations on the size of the fan.

Each type has its own benefits and downsides

#1. Time needed to get a roasting shift done.

Drum coffee roasters take 15 to 20 minutes to roast the green coffee beans, while air coffee roasters just spend 6 to 8 minutes to do the same work. So, drum roaster is faster than air roaster in time of roasting. Moreover, the longer and hotter coffee beans are roasted, the more aroma and flavor of coffee will go away.

#2. Temperature consistency.

Fluid bed air coffee roasters are able to provide consistent temperature to all coffee beans. The air roaster is called fluid bed air because of the fluidity movement of coffee beans, allowing them floating on the bed of air in the roasting chamber, which make all beans be heated at the same temperature at the same time. Drum coffee roasters, in the meanwhile, let the beans sit in the drum and shake them with a mechanical arm. That’s why the beans which can reach to the drum surface can be roasted at the top temperature. It results in the uneven roasting coffee beans.

#3. Chaff capturing and removal.

Drum coffee roasters can trap and burn the chaff. In here, chaffs mean coffee skins (such as silver skins) or foreign matter. When being rotated in a drum roaster, silver skins which stick with coffee beans will be opted out and burnt, causing smoke or burnt flavor of roasted beans. In other hand, in air roaster, when the chaff come out of the beans, they will be taken to a cyclone and then fall into the chaff collector to avoid burning and affecting coffee flavor.

#4. Roasting accuracy.

Air coffee roasters are generally easy to use. Air roasting provides roasters an exact control over each batch of coffee. The beans are roasted based on the precise temperature, not color like drum roaster. When each batch of coffee is roasted to precisely the same temperature, roasters are better able to yield coffee batches that are consistent in color, flavor, undertones and aroma. However, drum coffee roasters which base on color, can offer the better and good-looking coffee beans. It also provides better body, a bit more sweetness and more “depth” coffee beans. Fluid bed air roaster tends to overwhelm drum roaster with a lot of advantages. And when using home-used coffee roaster, let’s consider some factors such as how well it works, how easy to use it at your kitchen, how easy to clean it, how convenient when placing, moving it around, etc.

To sum up, coffee roasters are machines for roasting green coffee beans at different degrees and temperature. There are two main types of coffee roasters – air roasters and drum roasters. Those two ones share some similarities and differences in terms of time to roast, temperature consistency, silver skins and foreign matter removal and roasting accuracy. Definitely, coffee roasters are playing a very important role on deciding the quality, taste, aroma and outside apperance of freshly roasted coffee beans.