Transforming green coffee intoroasted beans draws together art,science, tradition and innovation

in an activity that can be performed on astovetop or in an industrial factory. At itsmost fundamental, coffee roasting is theapplication of dry heat over time. Thesetwo core variables can be plotted as a roastcurve, but what appears as a straightfor-

ward curve is the result of meticulousmonitoring and adjustment of manymore factors, performed by individualsand programmed systems.

Sight Roasting: Artisan at All ScalesThe most traditional approach to coffeeroasting is one that relies solely on the fivesenses. Today, iterations of this original

method are referred to as “sight roasting,”“artisan roasting” or “craft roasting.”Companies using these terms may definethem slightly differently, but all threeimply that–no matter the volume–theroasting process is ultimately controlledby a person.

Chris Calkins began his coffee careerdeveloping Starbucks’ restaurant divi-sion and then launched the Spinelli’snational wholesale and retail chain.Calkins has experience managing vol-umes of consistent quality, but he nowspends a few days a week at Brooklyn’sPulley Collective roasting 35kg batchesfor his company Gotham Roasters, sup-plying the Manhattan café, ProdigyCoffee. “My desire to sight roast is notjust because I am stubborn, it is because,even with a machine as sophisticated asthe Loring, I want to remain the chef atthe stove using my instincts. I feel this iswhere the art resides.”

Even when an individual rather than

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Some Like It Hot: Roasting Techniques and TechnologiesTradition and innovation converge in the process of roast-ing coffee. Empirical data collection and nuanced sensoryobservation offer different advantages when pursuingvarious end goals for specific coffee customers.By Rachel Northrop

The most traditional approach to coffeeroasting relies solely on the five senses.

This method is known as “sight roasting,”“artisan roasting” or “craft roasting.”

a program has the final control, softwarecan be used to track adjustments madein order to provide a quantitative sum-mary to accompany the qualitativeresults of a roast.

Stacy Hawkins, roastmaster forBirmingham, Ala.-based H.C. ValentineCoffee Company noted, “there are a num-ber of variables that can affect how a batchroasts, so there is a definite need forhuman input and the ability to adjust set-tings and profiles. We roast 6,500 lbs perweek on an Allen-Bradley touch screenmodule to control and monitor all func-tions of a Probat G60, gas-fired, soliddrum roaster. This allows for control ofthe supplied heat and air flow as well aseasy monitoring of bean, air and after-burner temperatures.”

The same technology can be used dif-ferently according to users’ needs andpreferences. Tracking the details of a roastprofile with digital read-outs is not thesame as deferring to software to makeadjustments that yield a given roast curve.Slight variations are what make all artisanproducts personal, from hand-assembledfurniture to hand-roasted coffee.

“It boils down to customer accept-ance. The parameters of what’s acceptablehave to be wider if you want craft roastingto be of acceptable consistency,” saidDonald Schoenholt of Gillie’s Coffee,Brooklyn, New York. Finding customerswho share a passion for craft is of coursevital, as is getting a feel for your equip-ment. No matter what equipment youuse, handling a roaster is, he said, “likedriving a new car; once you get used to ityou can make it to anything you want.”

The Fast LaneJohn Larkin, owner of John Larkin andCompany, the Denville, N.J.-based roast-ing equipment installer and servicer,noted that scale and speed of growth canhave a driving effect on equipment needs.“As a company grows into producing larg-er batches, the features of some of thelarger roasters with patented air flows,heat transfer, can become interesting, evenif these were not features available whenthe master roaster first learned to roast. Itis kind of like shopping for a new car. Youdon’t necessarily always buy the samemake and model and trim. You ask your-self, “How much of a car do I need? Whatdo I want or need it to do? How much doI want to spend?” And you should alwaystest drive before you buy.”

Across the industry there is a rich her-itage of sight roasting on all scales, butthis legacy in no way impedes advances inautomated and software-controlled tech-nologies that are shaping coffee roasting,present and future.

Technologies for Every ScenarioThe spectrum of roasting technologiesavailable today encompasses diversehardware and software, includingadvanced platforms for measurement,analysis, and control of the intricaciesinfluencing the roast curve and otherdimensions of final quality.

One of the newer additions to thespectrum of drum roasting equipment isLoring Smart Roaster, Santa Rosa, Calif.“The Flavor-Lock Roast ProcessTechnology is unique to Loring SmartRoasters. The design uses a near-zero oxy-

gen atmosphere in the roaster, along withincreased humidity, to help preserve theflavor components of the beans. Theatmosphere in the roasting chamber is sta-bilized so roasts can be accurately repeat-ed regardless of the weather, accountingfor temperature, humidity and barometricpressure,” said Robert Austin, presidentand CEO. Loring’s combination of tech-nologies offers not only “true repro-ducibility in repeating custom profiles,but also an 80 percent fuel savings whencompared to a roaster that requires anafterburner to comply with air emissionstandards,” he said. Loring’s various drumroasters handle batches from 15 to 70kgs.

At the other end of the spectrum, thefluid air bed RFB (Rotational Flexible

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The time/temperature curve is crucial for aromaformation when roasting coffee so Bühler devel-oped systems to influence the shape of curve.

Batch) roasters of processing and roastingequipment manufacturer NeuhausNeotec, Hamburg, Germany, aredesigned to roast several thousand kilos ofgreen coffee per hour. “The RDRFRoaster combines drum and direct airfeeding technology, with a freestandingheater and conduction of the hot airthrough a pipe to the roasting drum,which is accessible from all sides. Themachine casing is only heated whererequired, affording the option to conductthe hot air directly into the drum to deter-mine airflow and temperature individual-ly. The necessary vacuum in the roastingdrum is always maintained, and air canbypass the roasting drum–and hence pastthe coffee–to regulate the coffee tempera-ture for targeted aroma development,”said Andreas Jürß, marketing manager,Neuhaus Neotec.

Jürß said coffee can be roasted with orwithout recirculation. “You may benefit

from the energy-saving poten-tial, and youcan process

recipes that prevent the return of the roast-ing air partially or completely with the samemachine. The ultimate aim is to offer amuch higher flexibility in coffee roasting.”

Flexibility can also come in the formof inverting the order in which technolo-gies are applied. Sight roasters use soft-ware to track decisions individuals makeat the roasting helm, but the software canalso come first, with individuals designingroast profiles that equipment executes.

“You can design a roast curve–forexample, to start slow and have a fastfinal, which would have a quite dramat-

ic impact on flavor and physicalproperties like bean swelling–and

the system will make sure itcan handle it,” said Dr. Stefan Schenker, head ofcoffee market segment for coffee processing androasting equipment manu-

facturer, Bühler, Uzwil,Switzerland, of Bühler’s IRC Process

Control software. “The time/tempera-ture curve is crucial for aroma formationand so Bühler developed systems toinfluence the shape of curve.”

Bühler’s highly reactive roasters canquickly modulate energy intake into theroasting chamber, requiring a process con-trol that can respond appropriately. Theirsoftware controls flavor by both influenc-ing mechanical changes that beans under-go and by controlling air and bean tem-perature to maximize consistency.“Whether you have seasonal changes orare starting on a cold roaster in the morn-ing, all these variables can be compensat-ed for,” said Dr. Schenker.

Currently, this software is available onBühler’s various drum roasters, but atInterpack in Düsseldorf, Germany, (May8-14), Bühler is presenting an innovationin “industrial-scale technology for fullprofile roasting–for both traditional andnon traditional roast curves. Drum roast-ers will always have their place in the mar-ket, but they have their limitations.Development of this new technologystarted three years ago and is now readyfor market,” said Dr. Schenker.

Fractions of a second differentiate oneroast from another, and developing waysto manage these minute details is invalu-able. Just as no athlete will replicate his orher race time down to the same numberof milliseconds, sight roasting will neverdeliver the precision of repetition thatautomated equipment controlled byadvanced software can.

Sipke de Schiffart, former sensoryexpert with Douwe Egberts (now D.EMaster Blenders), Amsterdam, and cur-

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Stacy Hawkins, roastmaster, H.C. ValentineCoffee Company believes human input is essen-tial when roasting, it cannot all be automated.

With Neuhaus Neotec’s RDRF Roaster, coffee can be roasted with or without recirculation.

rent micro roaster, noted that all roastingtechnology, in its essence, is a tool fordelivering coffee’s inherent attributesmore completely to consumers. “I alwayssay, ‘roasters can be simple, it’s the coffeethat is complicated.’ Aromas are a com-plex matter. There are at least 1200 differ-ent aroma components in coffee of whichmaybe 700 are known,” he said. “Thesearomas in total give us the smell as we

know coffee, the crucial question remains,‘What does your customer like best? Howcan I find the optimum roast curve tobring out the best aromas?’”

Begin with the End in MindConsumers build strong emotionalattachments to aromas and flavors, so ifthe goal is to deliver these same aromasand flavors year after year, then the

automation of roasting with profile-saving equipment and responsivemachinery is a must.

If the goal is to offer a variety ofnuanced coffees that vary from microlotto microlot, then the roasting processmust rely on a person who can illuminatethese idiosyncrasies by applying his or herbest judgment to each roast.

Decisions around which roastingtechnologies to employ are most heavilyinfluenced by the desired end product.When that is clear, roasting techniquespractically choose themselves. Larkin sur-mised, “the ultimate determinant is reallythe ability of a roaster in your price rangeto produce the cup that has brought yousuccess to date.”

Rachel Northrop is the author of “WhenCoffee Speaks: Stories from and of LatinAmerican Coffeepeople,” a compilation ofinterviews with people working along thecoffee production chain. Visit whencof-feespeaks.com for more information and toorder copies of the book.

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Loring Smart Roasters’ newFlavor-Lock Roast ProcessTechnology uses near-zerooxygen atmosphere in theroaster, along with increasedhumidity, to help preservethe flavor components of the beans.