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Lot-Specific Roasting: Craft Roasting for Authentic Flavor

By Timothy Hill

What is the best roaster? Timothy Hill, head roaster for Counter Culture Coffee explores the different characteristics of their three roasting machines and recounts his personal experiences roasting on each of them.

If you’ve got it flaunt it. If a coffee has a beautiful delicate acidity, why cover it up? If a coffee has a killer body, the roast should support and emphasize it.

In the last few years, more roasters than ever are finding ways to accentuate a coffee’s natural character, or terroir, as opposed to roasting everything with the same profile or level to create a house blend.

At the same time, roasters are being manufactured with more and more control to manipulate those unique characteristics. You can now map out temperature curves and set points, set the roaster controls to ramp “x” number of degrees a minute for “y” number of minutes and change the exhaust fan speed to match. The flexibility and dynamic nature of current roasters are light years ahead of where they were 10 years ago. The question I have been asking myself is: what is the role and function of greater control and the diversity of roasting machines offered in today’s market?

The Best Roaster?
In coffee there is an obsession with being the best. What makes something “the best?” What is the best coffee? What is the best espresso? The same goes for roasting, which is the best coffee roaster? As a roaster, this is the question I get more than any other, and I love it because it represents a desire to do things better. Recently, I have adopted a standard answer to the question of what is the best, and that answer is “There is no such thing.”

There is no question that roasters are built with varying degrees of quality. However, one can look beyond just the quality of materials and build. A roaster’s design strongly affects the way it roasts, and no roaster can be the best at everything. I believe that statement even holds true under today’s ultra controlled roasters - no matter how many parameters the user can manipulate, there are inherent qualities to the build of every machine that affect flavor differently, and cannot be changed from one roast to the next. For instance: What does having a double-lined drum do to the flavor? Or perforated drum? Does a jet burner or power burner affect flavor? How thick is the faceplate and what is it made out of? How much heat retention does the roaster have based on insulation? And then, in that certain indefinable quality that cannot be measured, a kind of “roaster mojo.”

Putting it To Practice
There isn’t really a way to test “roaster mojo,” but by looking at the build of roasting machines, there are roast characteristics that cannot be replicated from one machine to the next based on the manipulation of control parameters. Four years ago I got a good glimpse of what this actually means when I started working for Counter Culture Coffee, which has taken this concept forward and not only purchased roasters based on it, but has fully integrated it into daily operation.

Walking into Counter Culture’s Durham, North Carolina roasting facility you can’t help but notice the Roure, a 60-kilo Spanish-made machine. The Roure is a drum roaster that blends the concepts of a fluid bed air roaster into one. A single 300,000 BTU side-mounted power burner looks more like a three-foot blowtorch than anything else. The high airflow sucks hot air from the burner into the drum through a vent in the faceplate, and you can hear how much air is being moved. While I wasn’t able to find the exact number, it does max out my anemometer at well over 6,000 ft/min. Coupled with the fact that it is a perforated drum, uncommon in modern drum roasters, with somewhat low insulation and a thinner faceplate (than our other two roasters), the replication of the roast profile would be nearly impossible on any other machine. Counter Culture bought this machine thinking of that unique design of convection, conduction and radiant heat. In this case, with the high airflow and perforated drum, the emphasis is definitely on convection. This supplies the coffee with a profile that tends to work well with coffees that are clean and bright. More often than not, washed African and Central American coffees reign on the Roure, where the roasting style complements their already crisp and higher note characteristics.

Comparing the Roure, the convection heat giant, to our other 60-kilo roster, the Renegade, is a study in contrasts. Not only do the roasters sound differently, they are really on opposite sides of the spectrum. While the Renegade has great airflow, coming in just over 3,000 ft/min, it has less than around a third of the Roure’s airflow. Also in contrast to the Roure, the Renegade’s faceplate is 1/3 of an inch thicker and probably weighs almost twice as much. This thick iron faceplate absorbs and radiates heat incredibly well, so while the Roure is all about the agility of roasting with convection heat, the Renegade is more about the depth you can create with emphasis on contact and radiant heat, with a good balance of airflow. Because of the delicacy of this balance, we needed greater controls over roast parameters. We ended up using a controller that can control temperature ramp rate, drum speed, PID set points for environment and bean temperature and can store profiles for every coffee we roast. The amount of control and replication is amazing. Roasts of the same coffee generally finish within seconds of each other, and constantly monitored drop temperatures rarely change. Cooling time is equally impressive. It will cool a coffee with a drop temperature around 445°F to room temperature in about two minutes. We found that the lower airflow, long roast times and emphasis on radiant and contact heat really emphasized sweetness and body in coffees. This made it the perfect roaster to complement our long, slow espresso roasts that could be challenging; decaffeinated coffees that sometimes can lack depth and body; and Indonesian coffees that benefit greatly from a machine that can emphasize sweetness and body. While we saw great benefits with those coffees there is always a constant reexamination, because one can never tell which coffee is going to benefit from which machine. There have certainly been times when a washed Ethiopian comes out better on the Renegade than the Roure, and there have been times when the Roure performs better with a Sumatran coffee than the Renegade. Experimenting can be tedious but pays off.

The Roure and the Renegade are Counter Culture’s primary production roasters, roasting 86% of our total coffee, but our third production roaster is just as important as the other two and happens to be the first roaster we bought, the 10-kilo Sasa/Samiac. For 14 years we have been roasting with the Samiac, and it has never ceased to be an integral part of what we do. The Samiac is well balanced: with a good amount of airflow at around 1,200 ft/min, great heat retention and a nice, solid thick cast iron faceplate. Three years ago Counter Culture started actively buying more microlots from our producer partners, everywhere from Colombia to Ethiopia, and the Samiac found its true niche. While we still needed it to do small roasts of certain coffees for espresso and a lighter or darker roast here or there, the more microlots we bring in, the more flexibility is needed from the machine. Over the years, the Samiac has evolved into a whole new machine. We have replaced the atmospheric burner with a power burner, changed our controls more than once and have added an AC inverter to the exhaust fan so that instead of using a damper to change airflow we just change the RPM of the fan. The result is an amazingly flexible machine. With all that flexibility comes constant adjustment, however, and this roaster can be the most challenging to roast on.

Exploring different expressions of coffee flavor in different roasters has been an eye-opening experience. From the particulars of roaster controls to the indefinable “mojo” of roaster flavor, one finds that differences between coffee roasting machines can be as wide as differences between the coffees themselves, making an incredible amount of variety and experimentation possible. Dispensing with the idea of “the best roaster” and instead exploring the unique idiosyncrasies of roaster design has been a rewarding and exciting process for me.

Tea & Coffee - April, 2008
Modern Process Equipment

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