Coffee roasting machinery--2008: to get a better view of coffee roasting technology today, we spoke with some of the top roasting machinery manufacturers serving the specialty and mainstream coffee industries and found out what's new in the areas of energy efficiency, emission control and what's guiding these refinements toward producing a better roast.

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Coffee roasting technology doesn't change all that often. However, roasting equipment manufacturers have recently been refining and improving the energy efficiency, emissions control and roast-profile control parameters of their products. Heat recirculation is one area that many manufacturers have improved on in recent years. Recycling heat produced during the roasting process can greatly reduce the amount of fuel needed to complete roasts, especially if roasts are conducted back to back. Heat re-circulation in a coffee roaster functions like a hybrid car, which channels the previously wasted braking energy back into the vehicle to optimize the number of miles per gallon.

Afterburners are another area where progress has been made. If you are in the roasting business, you probably know that an afterburner is required in most regions of the country to eliminate the smoke and odor that coffee roasting produces. These afterburners, however, sometimes require three times as much fuel as the roaster itself--thus, the afterburner's reduction of emissions during the roasting process is really something of a shell game, substituting one harmful emission for another. Work is in progress to reduce the total emissions generated from roasting coffee.

Diedrich Manufacturing, Inc.

Since the inception of Diedrich Manufacturing, Inc., whether it is with their infrared burners, heat regeneration technology or catalytic oxidizers, the environment has always been something the company's president, Stephan Diedrich, has been concerned with, according to Shawn Contreras, marketing and business development manager of Diedrich Manufacturing, Inc.

Contreras explained, "Conservation has always been part of Diedrich Manufacturing's operating strategy. We always want to save fuel so we use heavier, more insular materials. Now, in this new age of environmental consciousness its more important than ever to conserve and going forward, customers are going to demand energy efficiency from their equipment manufacturers." With that in mind Contreras continued, "We offer two options for oxidizers, cost being one main factor, the traditional thermal and the more expensive, but more energy efficient catalytic oxidizer. The traditional afterburner is a thermal oxidizer, which adds temperature and turbulence in a large cylinder and also requires a large amount of fuel and combustion to eliminate smoke. But what we're doing with the catalytic uses about 1/2 the fuel and then the catalytic element eliminates the rest of the odor and smoke. The catalytic oxidizer can fit onto any of our 3-70 K roasters. Our infrared [more direct and precise heat] burner uses 1/3 of the fuel of standard burners ... the atmospheric 'gas jet' burner 99% of our competitors use which roast with a 'dirty burn' emitting various effluent gasses that are uncombusted ... carbon monoxide NOx [Nitrogen Oxides] etc, these gasses are produced but not burned off in many cases," Shawn informed. "Even on our in-store roasters, regeneration of heat gathering is standard. We utilize heat sinks that capture and store heat energy and put that back into the roaster. When roasting, you're heating up the air and metal of the drum; the metal heat sinks capture that energy they continue to raise the temp inside and around the drum even if you stop the gas-flow momentarily," said Shawn.

Loring Smart Roaster

As the designer of the KestrelS35 Smart Roaster, Mark Loring knows a thing or two about optimizing roasters for fuel conservation and pollutant reduction. Although Loring Smart Roast is still relatively unknown within the roasting community, Loring told us, "The market is mainly dominated by a few larger manufacturers and I wouldn't be entering the specialty coffee roasting equipment market and try to compete with them if I didn't feel I had something very special to offer."

The Smart Roaster uses a patented method of heat recirculation to reduce emissions and conserve fuel as well as an innovative coupling of the cyclone and the burner. It roasts a half bag at a time so its still a bit too large for most roaster-retailers, but if you're business requires that kind of capacity, an added bonus is the fact that the Smart Roaster doesn't need an afterburner.

"I think many roasters who market organic coffee are indeed worried about the environmental impact of coffee roasting but there just haven't been any alternatives to a well maintained catalytic incinerator until the Smart Roaster, and as good as a catalytic incinerator can be, it's still not as good as a Smart Roaster," Loring opined. "It turns out that our customers, especially our first customers; the early adapters are some of the most ecologically conscious people on the planet. They sought the greenest product and learned about the project I was working on back when I was totally unknown. These are the kind of people who most often consider the ecological impact of every aspect of their business and their lives, not only where they source their coffee or which biodegradable cups they use but everything. What they taught me, and I'm always learning from them, is that it's not so much a marketing decision anymore ... it's a lifestyle decision. They have made a quantum change and there is no going back. And that is why they bought a Smart Roaster. I think our new machine is the best alternative to a conventional drum roaster or a fluid bed roaster--even with the best of external incinerators--and with a fuel savings of up to 80%, well that's unbelievably good," Loring asserted.

Probat-Burns

Memphis Tennesee's Probat's Neptune roaster elegantly addresses environmental issues by incorporating energy optimization technologies developed by their experts. These technologies include forward-looking controls based on pre-programmed roast profiles, which conserve gas by knowing exactly when the roaster needs or does not need more heat. The Neptune also features heat recirculation technology (which has been in use on many Probat machines for years) whereby residual heat is piped back into the burner, thus conserving fuel and optimizing heat energy over time and roast volume. This conserves both energy and the environment by reducing the amount of total exhausted CO2 and NOx.

Heat recirculation saves about 40% in total fuel consumption when compared against traditional drum roasters. Continuing along this line of efficiency improvement, Probat has introduced a new option in afterburner technology. In addition to thermal oxidizers (afterburners that operate around 1400[degrees]F), and catalytic oxidizers (more efficient afterburners that operate at about 800[degrees]F, thus using less fuel,) Probat now offers their "FRTO," the Flameless Regenerative Thermal Oxidation unit. The FRTO not only uses about 50% less fuel than the catalytic oxidizer but it also further reduces NOx emissions. Larger Probat Roasters can also direct exhaust heat into the "preheating reactor," pre-heating the green coffee batch to a pre-determined temperature just prior to entering the roaster itself. Probat calls this their "green coffee preheating technology." This inventive process has no effect on the taste or cup quality of the coffee but saves approximately 20% in energy consumption and also increases roaster capacity by approximately 20%.

Economies of Scale

At this point in time, if you have a roaster that costs about $20,000, you'll have a hard time obtaining environmental control units that don't cost the same or more than the unit itself. The cost of environmental controls versus the cost of actual roasting equipment has been a thorn in the side of the industry for some time now. As the political climate (no pun intended) moves toward acceptance of climate change as a human-made (or human-aggravated) phenomenon, stricter emissions legislation is bound to follow. What is becoming increasingly apparent, however, is that it just might be the case that an energy-efficient roast might even be a better roast so the work toward lower emissions might also lead to better coffee (we're crossing our fingers on this one!)

Only by being pro-active will our industry be able to stay one step ahead of future, pollutant-restricting legislation that, while it may not be specifically aimed at the coffee industry, will affect us just the same. Coffee equipment manufacturers are fighting that fight on our behalf and we thank them for their hard work.

In the meantime, someone out there (we're looking for this person) should be able to confirm that the coffee industry, overall from seed to cup, actually sequesters more carbon than it releases (as carbon dioxide) ... even if this should be the case, though, it will never be an excuse to be wasteful of fuel, but it might be a source of some good PR and might even get a regulator to give the coffee industry a break once in a while!