There are two ways coffee is roasted commercially: drum roasting and air roasting. Drum roasting is where the beans are put in a drum or similar container, heated and “stirred” until they are nice and hot and roasted. With air roasting (also called fluid bed roasting) the beans are put into a clear heavy glass chamber. Hot air jets through the chamber, roasting the beans as the air makes them “dance” inside the chamber. Think of an air popcorn popper and you’ve got the image.
When we started Frankly Good Coffee we decided to air roast using Sonofresco roasters. Mostly because we knew our business model would begin with roasting coffee in open air farmers markets – so we needed a portable, easy set up. We saw this method and model first hand with Adventure Coffee Roasting in Tuscon Arizona and knew we could do something similar in the Las Vegas Valley.
The main difference between air roasting and drum roasting is the taste and feel of the coffee as you drink it.
Air roasted coffee has higher acidity, which means that it tastes “bright,” “crisp,” and satisfying first thing in the morning. Air roasted coffee tends to grind more consistently, leaving less soluble material. This means the coffee has a lighter mouth feel and less body.
The chemical change in the bean that results from roasting is achieved differently in each method. In drum roasting the final temperature is much hotter (sometimes up to 800 degrees F). This, combined with the need for the beans to be “stirred,” can sometimes produce charring, which leads to bitterness, burnt taste and some other side effects.
With air roasting the beans are more uniformly roasted. Air roasting is typically done in smaller batches, which allows for tighter control over the process.
Air roasting produces:
- A smooth cup of coffee
- Great taste and intense aroma
- Rich flavor – full body can be achieved by French pressing (our recommended brew method)
Obviously, we’re advocates of air roasting because we believe in it and our business model is built around it. The truth is, though, that you should experiment. Don’t shy away from trying different types of coffee from different vendors. As long as you’re buying from a trusted vendor who can tell you when the beans were roasted, your coffee drinking can be dynamic and inspired – rather than mediocre and rote.