Roasters Rock

Where Traditional and Functional Collide

Seo Duk-Sik and Rocky Rhodes - paintAfter enough time in the industry, one gets fewer and fewer moments of surprise. This was one of those moments. What would you say if you were offered the chance to roast on a charcoal fueled roaster? Of course you say “yes.” Then you quickly follow that with, “Huh? How does it work? Is it a drum roaster? How old is it?” The opportunity to try something new in roasting, even if it is something old, is fun, and you should never pass on the opportunity.

If you find yourself travelling outside the US on coffee business you are likely to be offered a tour of coffee houses in the area. It is your host’s way of saying we are proud of what we do and want to share it with you and the United States. It is a great comfort to know that everywhere in the world there is 3rd wave coffee being delivered.

In South Korea, Seoul in particular, great coffee is everywhere you turn. The study of coffee and implementation of best practices is on every corner. It is such a vibrant coffee scene that ‘really good’ is expected and ‘excellent’ is easy to find. So good is the coffee that differentiation is harder to achieve. A new phenomenon in coffee is at hand which has been driven primarily though the Barista profession. Doing something ‘different’ to get to that excellent cup.

These ‘different’ things include menu pairings, new dripper systems, 1 kilo roasters in the shop, roasting one cup’s worth of beans over the stove to order, and other really unique things. Some things, however, reach to the past for that differentiation.

In Japan, different fuels were used in roasting coffee. One readily available source of fuel was charcoal. Fuji Royal built a roaster to use this fuel in a small batch drum roaster. The flavor that came from this charcoal-fueled roaster became uniquely associated with Japan.

A Korean coffee enthusiast studied roasting in Japan and brought that style to Seoul. Seo Duk-Sik has expanded his talent and coffee enterprise and sells a great deal of his coffee back to Japan. He started Kaldi coffee in Seoul and moved his roasting facility out of the city where there was more room for production and less restrictions on emissions. The flavor holds true to this ‘Japanese Style’ of roasting.

Charcoal roasting - paintAfter a tour of the plant and an opportunity to run the machine for a couple of roasts, some interesting discoveries were made. The most important of which is that there are different tastes for different folks. Who is to say what is right or wrong? With this charcoal roaster, tradition and brisk sales indicate that Kaldi is ‘right’ with this style because sales are increasing by holding on to the ‘old ways.’ Remember that coffee is hundreds of years old and ‘Specialty coffee’ is only about three decades into its infancy.

The Fuji Royal charcoal roaster is a pretty unique beast. It operates with two airflow motors; one for roasting and one for cooling. The chaff collector is unique in that it has a water curtain that the smoke must flow through before entering the cyclone chamber. This is necessary for a charcoal roaster because embers fly all over the place and are easily sucked into the exhaust. Embers are extinguished and then the water leaving the cyclone is screened and the wet chaff is collected. Smoke that remains exits normally through the exhaust pipe.

Traditional and functional aspects of the roasting are often at odds with each other on this machine. The fire box is stoked with charcoal, ignited by gas, and then the gas is cut off. There is an art and a discipline to placing the pieces of charcoal to produce an even heat directly below the drum. During the roast certain pieces are removed or added to increase or decrease the heat. Different ways of introducing oxygen to the system also allows flexibility in temperature control.

Airflow through the drum is very low so as not to suck up too many embers. To increase the amount of air flowing through the beans it uses a completely perforated drum that sits directly above the fuel source and all of the heat is pulled through the coffee. This produces a lot of radiant heat mixed with some convective. This would be the opposite of more recent drum roaster designs where higher airflow produces more convective heat and the hot steel of the solid drum produces contact heat. If you think the flavor profile would be different, you would be right!

The low convective heat causes a roast to take 20 minutes or more. Just before the roast comes out Seo Duk-Sik dampens the airflow allowing the charcoal smoke to enter the chamber and add what is almost a mesquite flavor to the beans. The result is a smoky, heavy-bodied, low-acid coffee. And it is this profile that is the signature taste for this kind of roaster.

While watching this process, it would be easy for ‘specialty roasters’ of the West to think of about a dozen ways to ‘improve’ the functionality of the machine. But as a good roaster must always do; figure out the outcome you want and then roast to that outcome. If the machine were changed, this traditional flavor would be lost. In this case the machine is perfectly functional for the outcome. And the resulting coffee resonates with Kaldi’s customers.

Being traditional is being unique, and unique has found a market amongst all of the other coffee shops.

Rocky Rhodes is an 18 year coffee veteran, roaster, and Q-Grader Instructor, and his mission now is to transform the coffee supply chain and make sweeping differences in the lives of those that produce the green coffee. Rocky can be reached at

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