Let’s talk about roasting methods
We talk a lot about roast degrees but sometimes we don’t pay much attention to HOW the coffee is roasted. There are several different roasting methods of coffee. Each comes with its own advantages and disadvantages, and the amazing thing is that each method brings out a very different side of the coffee. Which means that it’s possible to experience three different flavor profiles of the same roast of the same coffee. How exciting!!
The roasting methods I’ll introduce down below is what I’ve found to be most common in Japan. Perhaps there are other ways of roasting which may be unique to your country or region.
1.Direct Contact Method
The Direct Contact Method or Chokka-shiki(直火式) is a roasting method where the coffee beans come directly into contact with the open fire source. The concept is quite simple. Similar to barbecue, flames come directly into contact with the coffee beans, but it’s contained in a spinning meshed steel tube and so the coffee beans are distributed and heated evenly. Direct contact with the flame brings about the many different chemical reactions to produce the familiar robust aroma of freshly roasted coffee.
There are many fans of the direct contact method, and some people say that this method brings out the full flavour, body and potential of the coffee.
What I’ve noticed, at least in Japan, is that this method is becoming less and less popular as time goes on. Nowadays, people are looking to roast their beans using other methods. Perhaps the coffee roasted like this is too strong, too intense and unsuited for people looking for coffee that’s light or easy to drink. I really like the coffee roasted with the direct contact method, but that’s just me. We all have our favorites and this is just one option out of the whole bunch.
2. The Hot Air Method
The Hot Air Method or Neppu-shiki(熱風式) is a roasting method that’s pretty much opposite to the one above. The flames don’t come into contact with the beans. Instead, heated air roasts the coffee. And when I say heated air, I mean extremely hot air. So hot that the whole process just takes a few minutes.
The way this works is having the heated air pass through a steel tube containing the raw coffee beans.
The resulting coffee tends to have a medium to light and clean body and a lot of fragrance. I think this method is most suitable when highlighting the unique aromas that you can find in single origin specialty coffee.
The way this works is by putting the coffee beans into a rotating metal barrel and then sending in very hot air from one end to the other. This is usually done much quicker than the other roasting method and is the norm for roasting very large batches of coffee. Many large coffee companies use this method.
3. The Semi-Hot AirMethod
This is kind of the in-between of the above methods. Instead of the flames coming into direct contact with the beans, they come into contact with a rotating steel tube. Think of the frying pan at home. The same applies here. The coffee is roasted indirectly through the heat of the steel drum. This method is by far the most popular and many roasters use this method. A lot of people say that this method brings consistency and control to the type of roast profile one envisions.
So there you have it.
Three different roasting methods that are common throughout Japan. The roaster machines are usually custom built or pre-built to fit the specific roasting methods the roaster envisions.
What roaster machine do you have? Or what roaster machine do you want to handle? Why so?
Let us all know.