May | J une 2018 - Roast Magazine
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Ma y | J une 2018
2 May | J u n e 2 0 18 3
4 May | J u n e 2 0 18 5
M A Y | J U N E 2 0 1 8
ta b l e o f c o n t e n t s
26 10 From the Publisher
Heat and the
Roasting Machine 16 News Item
La Cosecha Es una
Redesigning the Legacy RP218 Course
Fiesta: Panama Debuts
a New Breed of Coffee
48
Festival
Spectroscopy Illuminated 114 A Life in Coffee
Craig Holt
A Practical Approach to
Determining Roast Development 120 Coffee Review
Organic-Certified
Coffees from Africa:
66 Benefits, Challenges,
Complexities
Developing Themselves
Washing Stations and Women’s 124 Flamekeeper
Your Coffee Roasters
Empowerment in Rwanda
Guild Needs You: Get
Involved in Driving the
84 New Guild Forward
Elevate Your Training Game 128 First Crack
Hot Products & Fresh
Is SCA Premier Training Campus Press
Certification Right for You?
136 Trade Show Calendar
100
The Effects of Total Water
138 Classified Ads
Hardness on Coffee Extraction 140 Advertiser Index
An Evaluation Using Espresso, Chemex and
Syphon Methods 142 Parting Shot
cov e r p h oto Pouring coffee at Caffeine Shinheon-ri in Seoul, South Korea. | Photo by Mark Shimahara
6 May | J u n e 2 0 18 7
8 May | J u n e 2 0 18 9
from the publisher
T
ombstones in the modern graveyard of business
are chiseled with the names of once-dominant
companies, like the most recent inhabitant, Toys-R-Us.
This graveyard is a surprisingly crowded place, as 52 percent of the companies on the
Fortune 500 list in 2000 “have either gone bankrupt, been acquired or ceased to exist,”
according to a 2014 report by the technology research and advisory firm Constellation
Brands. Whether unwilling or unable to adapt to change, complacency has been one of the
leading causes of death among these companies.
Complacency leads to companies becoming irrelevant. When was the last time you
shopped at Toys-R-Us? If visited a Toys-R-Us store, or even shopped online with the retailer
during the past couple of years, you would not have described the experience as “modern”
or even “enjoyable.” The stores were dated, and the company’s web experience provided the
bare minimum needed to order a product. This leads to a question we all must face: What
amount of our limited time, money and resources should be dedicated to staying relevant?
For a small company, these decisions become even more critical as major
miscalculations with resources, products or branding bring consequences ranging from
inconvenient to catastrophic. So we are left with the need to move forward quickly, but
smartly. Nowhere is this truer than in decisions related to hiring. New people come with new
ideas, which are critical to maintaining relevancy. No matter how many books or blogs you
read or events you attend, you are still constrained by your unique experiences. I believe
relevancy comes from the combination of ideas tested and deployed quickly.
Along these lines, I would like to introduce Lily Kubota as Roast magazine’s new digital
content manager and Daily Coffee News contributor.. Lily brings to our team a diversified
set of skills, ideas and experiences honed from many years working in our industry. Roast is
counting on her creative energy to keep us moving forward.
We are very proud of our bi-monthly magazine; Daily Coffee News; our Korean, Spanish
and Chinese licensing partners; The Book of Roast; and now our new seed-to-cup photo book,
Coffee Covered. Keeping Roast as a frequent and continuing presence in our customers’
minds is our key to staying relevant. Our strategy to achieve this is to provide valuable
content to our audience in a variety of forms. We are not looking to make the Fortune 500,
but we sure aren’t going down the Toy-R-Us path.
Warmest Wishes,
10 May | J u n e 2 0 18 11
12 May | J u n e 2 0 18 13
publisher
Connie Blumhardt
e d i to r
Emily Puro
a r t d i r e c to r | w e b m ast e r
Jeremy Leff
o p e r at i o n s m a n ag e r | a dv e r t i s i n g sa l e s
Claire Harriman
claire@roastmagazine.com
c i r c u l at i o n m a n ag e r
Beth Winburne
d i g i ta l co n t e n t m a n ag e r
Lily Kubota
co n t r i b u to r s
Luz Stella Artajo Medina Joe Marrocco
Manuel Barsallo Jason Sarley
Jim Brady Mark Shimahara
Beth Ann Caspersen Carl Staub
Kenneth Davids Aleida Stone
Rob Hoos Spencer Turer
Josh Little Kim Westerman
Juan Lee Lui
co p y e d i to r
Kelly Stewart
e d i to r i a l a dv i s o ry b oa r d
Phil Beattie, Dillanos Coffee
Darrin Daniel, Alliance for Coffee Excellence
Mike Ebert, Firedancer Coffee Consultants
Peter Giuliano, Specialty Coffee Association
Karen Gordon, Coffee Holding Company
Rob Hoos, Nossa Familia Coffee
Sevan Istanboulian, Cafe Mystique Coffee Inc.
Scott Merle, La Minita Coffee
David Pohl, Pohl Coffee Consulting
Joseph Rivera, Coffeechemistry.com
Donald N. Schoenholt, Gillies Coffee
Paul Thornton, Paul Thornton Consulting
Spencer Turer, Coffee Enterprises
Geoff Watts, Intelligentsia Coffee
da i ly co f f e e n e ws
www.dailycoffeenews.com
Nick Brown, Publisher
Howard Bryman, Associate Editor
r oast m ag a z i n e
1631 NE Broadway, No. 125
Portland, OR 97232-1425
P 503.282.2399 F 503.282.2388
Email roast@roastmagazine.com
Roast magazine is published bi-monthly by JC Publishing. One-year
subscriptions are $35 for subscribers with mailing addresses within the United
States; $55 US for Canada; and $65 US for all other countries. The contents of
this publication may not be reproduced in whole or in part without written
permission from the publisher. Postmaster please send address corrections to:
Roast magazine, 1631 NE Broadway, No. 125, Portland, OR 97232-1425.
Copyright © 2018 Roast magazine. All rights reserved.
v i s i t r oast o n l i n e at
roastmagazine.com
14 May | J u n e 2 0 18 15
news item
news from the world of coffee
L A C O S E C H A E S U N A F I E S TA
Panama Debuts a New Breed of Coffee Festival
By Emily Puro
Jorge Chanis (right) and Giancarlo Effio of Mentiritas Blancas, a multiroaster coffee shop
in Panama City, harvesting coffee on the Lamastus Family’s Elida Estate. | Photo by Manuel
Barsallo (coffeetologist.com)
I
n 2004, in preparation for the Best of Panama specialty coffee competition, the
Peterson family tried something new: They separated the coffees from different
areas of their farms into individual lots. One of those lots was a geisha variety,
grown high in the volcanic hills of the Chiriquí province, and when the judges
cupped it, it rocked their world.
That Hacienda La Esmeralda geisha won the 2004 Best of Panama
competition, setting a record auction price of $21 per pound (a shockingly high
price at the time, though in 2017 the winning coffee, also from Hacienda La
Esmeralda, set a new record price of $601 per pound). Since then, Panamanian
producers have separated their coffees by variety and quality and experimented
with different processing methods to distinguish their lots. Natural-processed
geishas, for example, have proven especially popular with Asian markets.
With relatively low production—Panama produced 95,000 (60-kilogram) bags
Boquete Tree Trek, owned by the Koyner family of Kotowa
Coffee, offers lodging, coffee and tea tours, zip-lining, birding of arabica during the most recent crop year, according to the U.S. Department
and hanging bridge hikes. | Photo by Manuel Barsallo CONTINUED ON PAGE 18
16 May | J u n e 2 0 18 17
n e ws i t e m | continued
of Agriculture’s Foreign Agricultural Service, well
below its neighbors in Colombia (14.7 million bags)
and Costa Rica (1.55 million bags)— producers in
Panama have long strived to maximize the return
on their limited supply.
Enter Jorge Chanis, a food writer, social
media influencer and event planner focused on
promoting exceptional gastronomy in Panama and
throughout Latin America. Chanis—along with a
group of next-generation Panamanian farmers and
roasters—believes producers here must improve,
expand and, most importantly, modernize their
marketing efforts in addition to continuously
improving coffee quality. La Cosecha featured a lunch hosted by Carlos Aguilera of Carmen Estate (left) and chef Patricia
“Panamanian coffee growers need to develop a Miranda (fourth from left), who runs a cooking and nutrition school for indigenous Ngöbe
women. A dinner party showcased produce from organic farmer Lourdes Guerra, who trains
mystique behind the terroir,” says Chanis, “behind
Ngöbe women in farming and agriculture. | Photo by Juan Lee Lui (juanleelui.com)
the microclimates, the mountains, the stories of
their families.”
Partnering with the Specialty Coffee Association of Panama THE EVENT
(SCAP), the Panama Tourism Authority, and numerous producers,
roasters, chefs and others, Chanis launched a new platform The inaugural event, held March 1–4, 2018, focused on five local
this year centered on celebrating the coffee harvest in Panama. producers (Janson Coffee Farm, Carmen Estate, Hacienda La
Called La Cosecha, which translates to “The Harvest,” it goes far Esmeralda, Lamastus Family Estates, and Kotowa Coffee), with farm,
beyond the typical specialty coffee event to highlight the culture, processing, and roasting and packaging facility tours as well as
community and cuisine of Chiriquí, where nearly all of Panama’s hands-on cupping, brewing and harvesting activities. La Cosecha
specialty coffee is grown. also featured meals showcasing locally harvested foods, a rum
“The Best of Panama is the biggest event the Panamanian tasting and two well-attended parties. Only two coffee-focused
coffee industry has, but it’s only for specialty coffee professionals,” publications (Roast and Standart, based in Slovakia) were among
Chanis notes. “They come, they judge the coffees, and they leave. the national and international media invited to cover the event;
La Cosecha is more about inviting everybody to fall in love with the the rest represented lifestyle- and travel-focused publications and
coffee and the farms.” social media influencers.
“La Cosecha is trying to build a sustainable tourism product
around coffee,” Chanis explains. “The flag is coffee, but around the
flag you need food, music, everything.”
THE PRODUCERS
The farmers—who all represent third- and fourth-generation coffee-
growing families—have lived, farmed, struggled and succeeded
together for the better part of a century, fostering a far greater
sense of community than competition. After a small group of them
founded SCAP in 1996, recalls Wilford Lamastus Sr., a founding
member and current president of the association, “We started
traveling together, helping each other, sharing knowledge and
buying seeds from each other. This is a big part of today’s success.
We are still doing this after more than two decades.”
“Panama is such a small producer that the demand forces us to
help each other to keep the quality and the good name of Panama
as a high-quality coffee producer,” agrees Carlos Aguilera of
Carmen Estate.
This sense of community extends to the indigenous Ngöbe
With the Pacific ocean and its colder climate to the north, and the Caribbean
Sea with its hot and humid airstreams to the south, Panama is home to a vast people who have worked in the coffee fields for generations and, in
array of diverse microclimates, creating a wide range of flavor profiles. many ways, share in the producers’ success.
Photo by Manuel Barsallo (coffeetologist.com) CONTINUED ON PAGE 20
18 May | J u n e 2 0 18 19n e ws i t e m | continued
“It is important to sell high, because it’s the best way to family’s 100-year-old business. In 2012, he opened a roastery and
reinvest in our No. 1 asset, our people,” says Wilford Lamastus Jr. cafe called Bajareque Coffee House in the Casco Antiguo section of
“Our workers are 95 percent Ngöbes from the Ngöbe-Bugle Indian Panama City.
reserve. We provide food, clothing and education for the kids, “I knew there was a potential for Panamanian citizens and
housing for their families, and for the teens and young adults we tourists to enjoy export-quality specialty coffee,” he says, referring
sponsor their universities. This is all thanks to the fact that we can to the fact that, as in many producing countries, the best coffees
sell geisha coffee at high prices.” typically are exported.
Ngöbe workers, he notes, no longer work only in the fields; Today there are four specialty roasters in Panama City and four
today they serve as roasters, cuppers, baristas, tour guides, mill multiroaster coffee shops. Collaboration trumps competition for
managers and quality control experts on coffee farms throughout them as well.
Chiriquí. “I roasted the first batches for the opening of at least three of
“Our governments have forgotten and marginalized these them,” says Lamastus Jr., “and alongside the roaster of Café Unido,
groups for over a century,” he adds. “Coffee is the opportunity for Alberto Bermudez, we do a talk and coffee activities every six weeks
them to grow.” to introduce the public to specialty coffee.”
La Cosecha is a “next generation” coffee event, so it’s not
T H E N E X T G E N E R AT I O N surprising it showcased farms where a new generation of coffee
professional is making its mark. In addition to Lamastus Jr.,
Lamastus Jr.—who played an integral role in designing La Cosecha 17-year-old Victoria Koyner led a tour of her family’s historic mill.
and bringing it to fruition—is involved in every aspect of his Representing the fourth generation behind Kotowa Coffee House—
one of the country’s most prominent brands—she highlighted both
the history of the business and recent innovations, such as the
family’s expansion into craft chocolate.
BEYOND COFFEE
While diversification typically means planting crops other than
coffee, the producers of Chiriquí have diversified in a different
way—by leveraging the natural beauty that surrounds them.
“We saw an opportunity to diversify for the growing tourism
industry here in Panama,” says Leif Janson of Janson Coffee Farm,
which offers farm and coffee tasting tours as well as hiking, birding,
kayaking, fishing and other activities.
The Lamastus family—whose Elida Estate is partially located
inside a UNESCO World Heritage Site called Parque Internacional
La Amistad—also runs both coffee and adventure tours. The Koyner
Wilford Lamastus Sr. (left), Wilford Lamastus Jr. (center), and Jorge Chanis
family has gone beyond tours to create Boquete Tree Trek, an
on the Lamastus family’s 100-year-old farm, Elida Estate. | Photo by Manuel
Barsallo (coffeetologist.com) ecotourism destination with lodging, coffee and tea tours, zip-
lining, hanging bridge hikes and birding.
While typical specialty coffee events “target only coffee
professionals,” says Lamastus Jr., La Cosecha is about “making it
friendly for coffee people and non-coffee people, so they become
coffee people after the event. If more people understand there
is high-quality coffee and a high value added to it, our farming
industries can keep growing.”
For details on La Cosecha 2019,
La Cosecha also featured meals by well-known Panamanian chefs, a tasting
follow @elbuendiente on Instagram, or
of locally produced Ron Abuelo rum, and two parties that brought together
what felt like the entire Panamanian specialty coffee community. Pictured: visit lacosechapanama.com later this year.
La Cosecha host Jorge Chanis (left) and roaster and photographer Manuel
Barsallo of Paddle Coffee (coffeetologist.com). | Photo courtesy of La Cosecha
20 May | J u n e 2 0 18 2122 May | J u n e 2 0 18 23
15th Annual
ROASTER
of the YEAR
COMPETITION
TWO ENTRY CATEGORIES TWO AWARD PACKAGES
Each award package includes:
Micro Roasting Category
roasting less than 100,000 lbs. per year • A FULL-LENGTH FEATURE story in the
November /December 2018 issue of Roast magazine
Large Roasting Category • $500
roasting more than 100,000 lbs. per year • A WEB PAGE on the Roast magazine website
for an entire year
JUDGING CRITERIA
• Company Mission
ENTER TODAY
• Company’s Commitment The deadline for
to Sustainable Practices submissions is
• Quality of Coffee July 27, 2018
• Commitment to Em- so don’t delay.
ployees and Educational
Practices
• Commitment to and In- SUBMIT YOUR
volvement in the Industry APPLICATION
• Innovations in Roasting,
Marketing and Business VISIT
Practices
ROASTMAGAZINE.COM
and click on
Roaster of the Year Award
OR CALL US AT
503.282.2399
CONTEST RULES AND THE FINE PRINT
Three finalists will be chosen based on the criteria written above. Contestants will be notified if they are chosen as finalists. At that time, each finalist will be asked to submit three differ-
ent 1 lb. roasted coffee samples. Coffees will be judged on aroma, color, imperfections, bean size and a clean cup. Coffees will be blindly judged by a professional coffee cupper.
CONTEST RULES: Deadline for submissions is July 27, 2018. Winner of the Roaster of the Year award will be announced in the Nov|Dec 2018 issue of Roast magazine. The winner will
receive notice of award no later than August 31, 2018. The Roaster of the Year will be presented to a company and not an individual. All entries become the property of Roast magazine
and will not be returned to applicant. Entries are judged by Roast magazine employees and Roast magazine representatives. Decisions of the judges are final. All scores are confiden-
24and undisclosed. Applicants can
tial either be a wholesale roaster or roaster/retailer. Applicants must roast their own coffee. By entering this competition you give permission to Roast
magazine to publish your name and likeness in association with this competition and the promotion of this contest.
May | J u n e 2 0 18 25Heat and the
Roasting
MaChine
Redesigning The Legacy Rp218 Course
by ROB HOOS
Introduction by Jim Brady
A S EDUCATORS, OUR GOAL IS to find ways to convey information
in a manner that turns it into knowledge. For the basics, such
as mathematics and literacy, we can use patterns and repetition, but
conveying a complex topic such as roasting presents challenges, as
it’s part science and part craft. The science is a constant, but the craft
portion relates to how the constants can be used as guides.
CONTINUED ON PAGE 28
Rob Hoos checking a roast. | Photo courtesy of Nossa Familia Coffee
26 May | J u n e 2 0 18 27HEAT AND THE ROASTING MACHINE | Redesigning the Legacy RP218 Course | continued
Introduction | CONTINUED FROM PREVIOUS PAGE
A few years ago, the Roasters Guild convective and radiant heat allows
Education Committee approached roasters to apply them purposefully.
Rob Hoos with a need to redesign By understanding the principles of
the legacy class RP218 Heat Transfer heat transfer and how they interact,
and the Roasting Machine. We were the practical application of the science
familiar with his book, Modulating The becomes clear. Hoos brought the
Flavor Profile of Coffee, which took simple method of profiling that was
a fresh and staggeringly simplistic the cornerstone of his book into the
approach to a complicated topic, process by which we apply heat. Using
providing an easy-to-comprehend this method, we can examine the
lexicon of the factors that influence the factors to observe during the roast and
primary algorithm of our industry— mitigate the potential for unexpected
replicating a coffee in exacting results. Charge temperature, weight,
fashion time and again, and using the turnaround, rate of change, moisture,
appropriate tools with other coffees density, weight mitigation and
to achieve the same predictable expansion all become mile markers on
results. Tackling heat transfer would a profile, along with the efficient use of
be an equally challenging task, and heat application.
in doing so, Hoos managed to apply The concept, at first glance, seems
the same approach of breaking down too good to be true, but it has proven
the numerous factors into easy- effective for relatively new roasters,
to-comprehend components, then and has even provided new insight
explaining how to apply them. for seasoned professionals. Creating
With the heat transfer curriculum, defects as a result of improper
we had to find a method to heat application helps develop an
differentiate between heat and understanding that can be achieved
temperature, which may sound the only through a hands-on experience.
same but are quite different. Further, It is counterintuitive to tell a student
a differentiation had to be made we’re going to scorch a batch, or
between temperature and slope, or we’re going to choke the airflow, but
rate of rise/rate of change. Hoos found trying to improperly roast a coffee
an interesting way to approach what batch perfectly illustrates the idea that
he referred to as the “uncertainty proper patterns yield proper results.
principle,” limiting the potential for Reviewing the equipment and
failure by stacking the deck with easily measurement tools helps solidify
understood concepts that quickly the concept that continuity and
become second nature. consistency are the result of patterns.
The technical portion of the class The use of appropriate measurement
details the methods we use to measure tools—such as a certain gauge and/or
temperature and heat. By introducing placement of a thermocouple with a
Understanding the science behind heat transfer multiple measurement standards, the specific type of roaster—helps students
and how your roasting machine responds to
information is accessible to students understand how to yield accurate
changing variables during the roast is key to
at all levels, and its application can information they can use in roasting.
the quality and consistency of your craft. The
hands-on roasting component of the legacy be based on each roaster’s individual The class is designed so that each
RP218 class gives participants a chance to see needs. Reviewing the Celsius, student walks away understanding the
how changing different variables affects a roast. Fahrenheit and Kelvin scales, and impact of heat and how it transfers on
Photos courtesy of the Specialty Coffee
discussing their histories, provides a roast.
Association
a “why” for a topic often inundated — JIM BRADY
with “hows.” Demystifying conductive,
CONTINUED ON PAGE 30
28 May | J u n e 2 0 18 29HEAT AND THE ROASTING MACHINE | Redesigning the Legacy RP218 Course | continued
RP 218 Reimagined | by R O B H O O S
Photo courtesy of Nossa Familia Coffee
t
he class formerly known as RP218 Heat and the Roasting
Machine has become an integral part of the new Specialty
Heat transfer
Coffee Association (SCA) Coffee Skills Program, as well as a valuable
standalone workshop. In its current form, it is difficult to distill Within the roasting system, we observe the continual increase of
the information presented into a single article—depending on temperature during the progression of the roast. Granted, at first the
the questions that come up, the session can take up to four hours. preheated thermocouple does a swan dive toward the turnaround
However, understanding and controlling heat transfer is the core point—where the bean probe reaches a relative thermal equilibrium
of what we do as roaster operators. We direct how heat enters the with the “bean mass” as it rapidly rises from room temperature.
bean to control the physical and chemical changes taking place (For the purposes of this article, we will not go into the intricacies
and bring out desirable flavors. of thermocouple measurement. To learn more about that topic,
In lieu of reducing this article to a brief summary that barely read “Through the Keyhole: Understanding the limitations of
touches the surface of each topic covered in the class, we’ll opt to thermocouple readings” in Roast’s September/October 2017 issue,
dive deeply into a few of the most important pieces of information. roastmagazine.com/thermocouple.)
To get the full story, you’ll have to sign up for an in-person class We need to differentiate between the changing measurement
with an authorized SCA trainer or roasting educator. Also, keep of the bean as it is being heated and the actual energy doing the
in mind that, while thermodynamics is a scientific discipline, the work. The measurement of warmth or coolness of an object at a
way it directly applies to how coffee roasters function is not well given moment, or the measurement of the heat energy within that
understood by many specialty coffee professionals. What we do substance, is represented by temperature. The energy itself, being
understand are trends, which we can use as guides. Hopefully, transferred from the source to the object, is what we refer to as heat.
future research will help us draw more definitive conclusions and The relative change in temperature over a period of time is known
attach numbers to the principles and practices described here. CONTINUED ON PAGE 32
30 May | J u n e 2 0 18 31HEAT AND THE ROASTING MACHINE | Redesigning the Legacy RP218 Course | continued
as the rate of change or rate of rise. Typically expressed as degrees Within most roasting systems, the bulk of heat transferred to the coffee
per minute, it’s derived from measuring the current temperature is convection. Even in drum roasters, considered to be quite conductive,
A S A REFRESHER, a thermocouple is
against previous values and determining a value of degrees
changed over a period of time. Because rate of change is derived
60 to 70 percent of the heat is transferred to the beans by convective
heat. The majority of the remainder of heat transfer is conduction. We
from previous temperature measurements, it is not truly predictive are not able to accurately measure the impact from the radiant heat of
a temperature measurement device that
of future temperature, but it is a good guide. the hot materials in a coffee roaster (metals, beans, etc.). The percentage
uses the difference in voltage between Within the roasting environment, there are three ways heat breakdown of convection, conduction and radiation will be different from
energy is transmitted from the source to the product. These three machine to machine, depending on design, material and size. (This is
two wires made of different types of means of transfer are convection, conduction and radiation. something the SCA looks forward to determining more accurately through
Convection is the transfer of heat energy by means of a fluid (i.e., continued research.) As you scale down in terms of roaster design, the
metal. The temperature is measured at the any substance that flows, which includes air). The fluid is heated metal thickness isn’t always scalable. This means that, for the most part,
by the source, then the fluid moves and heats the object by means smaller roasters will have a larger amount of conduction due to thermal
junction of the two wires, which typically
of direct contact. In terms of roasting, convection is almost always capacitance (the ability of the machine to retain heat energy) stored in
forced (movement caused by a fan) and specifically refers to the the heated metal and a generally higher metal-to-bean ratio. Additionally,
are sheathed in a metal coating. This
movement of air from a heat source through the drum/coffee. when looking at fluid-bed roasters, the percentage of convection is
differs from a thermometer, which uses Conduction, on the other hand, is the direct heating of the object significantly higher, but there is still some conduction and radiation.
through physical contact with another solid. In terms of roasting What I hope people take away from this is the significance of hot
the known expansion of a material (liquid coffee, this happens when the beans come into direct contact with airflow in roasting machines, and the impact it has on our ability to roast
the faceplate, drum wall and other beans. Radiant heat, on the other quickly and at larger capacities. Roasters need to make sure the airflow
or solid) to measure temperature based hand, is caused by photons being emitted from a heat source and in the roasting system is unencumbered so it flows freely. (Clean your
causing heat energy to be transferred to an object. Radiant heat is ventilation, avoid back pressure, and exhaust in a short, uncomplicated
on changes in volume or size. Roaster Rob Hoos checks the progress of a roast during a training
different from other forms of heat in that it does not require contact manner.) It also means we should optimize our use of airflow in roasting. at the Roasters Guild Retreat 2017. | Photo courtesy of the Specialty
with either a solid or a fluid and can happen in a vacuum. CONTINUED ON PAGE 34 Coffee Association
32 May | J u n e 2 0 18 33HEAT AND THE ROASTING MACHINE | Redesigning the Legacy RP218 Course | continued
as the developing gases are not able to escape as quickly as
Heat Transfer and the Bean they are being formed. The book Espresso Coffee: The Science
of Quality, edited by Andrea Illy and Rinantonio Viani, asserts
At this point, we’ve discussed only how heat energy moves from the that the bean potentially can reach an internal pressure as high
heat source to the bean. We haven’t discussed how heat energy is as 25 atm (units of atmospheric pressure; 25 atm is about 367.4
received by the bean. The heat energy first contacts the surface of the psi). This means that in addition to heat entering and exiting
bean, whether through convection or conduction. From the surface, the bean, we have a rather significant amount of pressure
the heat energy then diffuses through the bean, eventually heating developing inside the seed. This changes numerous factors,
inner parts. Although diffusion is a fairly straightforward concept, including the rate of chemical reactions and the boiling point of
because of the interplay of moisture and pressure with the incoming water, leading to a thermodynamically complex system.
heat energy, the way this plays out is a little convoluted.
As heat energy moves into the bean, it comes into contact with
water (both water from the original moisture content of the bean as Controlling Heat Transfer
well as water being generated by chemical reactions). As the heat
moves through the bean, it forms an evaporative front, where the When it comes to controlling this crazy mess of how heat is
water is turning into steam. The pressure from this expansion causes transferring to the bean and the rate at which it is permeating
the water that’s able to exit to be forced out, while the water that is the bean, we have a few options. Depending on the construction
unable to exit increases the internal pressure. As the water transitions of the roaster and how many features you have included, there
from liquid to gas, the energy requirement is significant. (This is are various ways to control how heat is applied, mitigated and
referred to as the enthalpy of vaporization.) The transition from 100 lost during the roasting process.
degrees C as a liquid to 100 degrees C as a gas requires more energy The beginning conditions of the roast are your first control
than the transition of liquid water from 0 degrees C to 100 degrees points for heat transfer, specifically how hot you charge the
C. Therefore, as the steam escapes the coffee bean, it carries with roasting machine, and how much green coffee you load into
it a tremendous amount of energy. At the same time, the water that the heated roaster. The thermal capacitance of the metal and
is not experiencing a phase transition from liquid to gas is helping the air in the roaster will deliver a certain amount of heat
to transmit heat energy to the core of the bean (as is the rest of the energy to the load of green coffee you’re adding. In general,
physical substance of the bean). the hotter you charge, the faster the initial part of the roast will
As a result, there is a dynamic transfer of heat occurring in the run; alternatively, a lower charge temperature will result in a
bean itself, with heat entering and transferring through the material slower roast. (The initial temperature of the green coffee and the
of the bean (including the unbound water) toward the core, and heat ambient temperature play a role as well.) Similarly, depending on
being lost by the generation of steam exiting through the surface of how much green coffee is added, one can control the ratio of hot
the bean. (See Figure 1, below.) In addition, this transition of water metal to bean mass and impact the rate of change in the coffee
from liquid to vapor (as well as the general heating of the bean) early in the roast. If the charge temperature is held constant, a
causes immense pressure to begin to build inside the coffee bean, larger batch of green coffee will result in a slower beginning of
the roast, and a smaller batch will result in a faster beginning
of the roast. Essentially, by controlling the initial environment
and amount of coffee, you begin to control the way heat will be
Figure 1 applied to the bean mass via the thermal energy stored in the
roaster.
HEAT ENTERING THE BEAN, A word on determining charge temperature: If available,
WALL OF EVAPORATION, AND PRESSURE FORMATION. it is better to plan your charge temperature based on the
environment/exhaust air thermocouple. Assuming you have the
same airflow, burner setting and drum speed (if available) every
time, a consistent return air temperature for a particular batch
size will give you fairly consistent results. It is more accurate
than charging based on the bean temperature alone because it is
less susceptible to the opening and closing of the drop door, and
it measures at the exit of the machine. Theoretically—if all the
other variables are constant (e.g., air speed and burner setting)—
once the air passing through the machine and heating the metal
of the roaster is at the same temperature as the previous batch
(measured by the exhaust air temperature), the machine should
have the same thermal store as that previous batch to begin
CONTINUED ON PAGE 36
34 May | J u n e 2 0 18 35HEAT AND THE ROASTING MACHINE | continued
roasting. The “bean” thermocouple is often located at an
area in the roaster where the airflow is intentionally lower
(the airflow will tend to enter the back of the drum and exit
at the top under the hopper, missing the bean probe almost
entirely on its direct path through the drum), and the mass of
metal above it is not taken into account in the measurement
of the bean probe with an empty drum. Even better, use a
combination of the exhaust/environment thermocouple with
an inlet air thermocouple to make sure the balance of energy
moving through the machine is similar. If you have the ability
to use both, you will be able to achieve greater consistency.
In addition to the charge conditions, various controls
are available to use during the roast, depending on the
manufacturer and model of roasting machine. These can
include heat-source output (burner, ceramic plate, electric
coil, etc.), airflow and drum speed. Keep in mind that more
controls are not necessarily better. More controls definitely
give the roaster more options, but for many people, it is at
best unnecessary, and at worst a distraction that makes
consistency even more elusive.
The heat-source control is quite possibly the easiest to
understand, as it is fairly linear. If you increase the intensity
of the heat source, you increase the amount of heat energy
being applied to the bean mass through both convection and
conduction. Similarly, if you reduce the heat-source intensity,
you decrease the heat energy being transferred to the coffee
via convection and conduction. Bottom line: A bigger flame
results in faster heating. (See Figure 2, below.)
Figure 2
BURNER SETTINGS IN COFFEE ROASTERS
In addition to controlling heat transfer through simple
flame adjustments, most roasters have a way to control
airflow. Airflow control is typically done through a damper,
although many machine manufacturers have switched to a
CONTINUED ON PAGE 38
36 May | J u n e 2 0 18 37HEAT AND THE ROASTING MACHINE | Redesigning the Legacy RP218 Course | continued
variable-speed fan to provide greater precision when it comes to Another element roasters can control, more so in the
controlling air speed through the drum. (A variable-speed fan is past few years, is the speed of the drum’s rotation as the
Figure 3 more precise because air is able to compress, so minor damper coffee is roasting. Though this is not always provided as an
AIRFLOW IN COFFEE ROASTING MACHINES adjustments frequently do little to nothing.) As mentioned earlier, additional control, it is becoming more common/available.
hot airflow is one of the primary means of delivering heat energy The relationship between drum speed and heat transfer
to the beans; thus, deciding how fast to move that air through the is linked with the inherent efficiencies of conduction
drum is important when determining the overall heat delivery to and convection. Convection is more efficient in terms
the coffee. of its ability to transfer heat from the heat source to the
One element worth considering is the balance of the burner’s beans. The faster the drum speed, the more the beans are
capacity to deliver energy (usually measured in BTUs [British lofted into the hot airstream, and the greater the relative
thermal units] or joules) in comparison to your fan’s ability to percentage of convection they receive. The slower the drum
move air (usually measured in cubic feet/meters per minute). If speed, the greater the percentage of conduction.
the fan is more powerful than the burner, higher airflow could There is, theoretically, the potential to produce a
mean lower heat transfer to the beans because the air cannot be centrifuge if the drum were to spin too quickly. This would
properly heated. However, if the burner is able to adequately heat force the coffee against the outer wall of the drum and
the air, a higher airflow should result in greater heat transfer to reduce convection significantly. That being said, most
the bean mass—to a point. Airflow isn’t quite that simple, as heat manufacturers limit the drum speed, most likely because of
delivery isn’t the only factor it influences. Airflow also determines mechanical limitations or to avoid having the beans sucked
how significant a burner adjustment will be in terms of the heat back toward the exhaust port at the top of the roaster.
transfer to the bean mass. With higher airflow, an adjustment This, in effect, minimizes the potential for centrifugal force.
to the burner has a potential to seem more drastic because a Regardless, the more the beans are exposed to hot air, the
reduction of the BTU output by the burner is exacerbated by fast- faster they will tend to roast, and the less hot air exposure
moving airflow. (See Figure 3, left.) CONTINUED ON PAGE 40 Photo courtesy of Nossa Familia Coffee
38 May | J u n e 2 0 18 39HEAT AND THE ROASTING MACHINE | continued
Figure 4
DRUM SPEED IN RELATION TO
HEAT TRANSFER IN A COFFEE ROASTER
they receive, the more slowly (and unevenly in extreme
conditions) they will tend to roast. (See Figure 4, above.)
All in all, roaster operators have a great number of
controls with which to fine-tune the type and speed of heat
transferred to the coffee during roasting. These include
charge weight and temperature, flame/heat-source settings,
drum speed and airflow. During roasting, we should carefully
monitor a number of factors, such as carryover heat (thermal
momentum), which is highly dependent on batch size and
roaster construction. That is where the craft of coffee roasting
comes into play. We learn how our roaster, ventilation setup,
coffees and other elements react to different heat application
controls, then we use the tools at our disposal to control
the transfer of heat energy to the beans in order to produce
our desired outcomes. It is multivariate, difficult and ever-
evolving, but it’s fun, challenging and rewarding as well.
Experiments TO
DO at Home
I would recommend all roasters buy some lower-priced
coffee to test the limits and controls of their machines in
order to better understand their own systems. The best way
to test this is by creating a baseline roast, then testing other
variables against that roast.
A baseline roast is created by using medium settings on
everything except your burner (which you leave at full heat
application) and manipulating one variable at a time. Charge
at the recommended weight and temperature for a full load
CONTINUED ON PAGE 42
40 May | J u n e 2 0 18 41HEAT AND THE ROASTING MACHINE | continued
TOP The RP218 Heat Transfer course is designed to help roasters
master the science and craft of heat application. BOTTOM Roaster Rob
Hoos cupping. | Photos courtesy of the Specialty Coffee Association
on your roaster (if you’ve been roasting on it for a while, use
your normal “full batch” settings) and roast to second crack
with burner at full the whole time. Then, adjust one variable
at a time. For example, to check the effect of airflow, leave all
the other settings the same as the baseline roast, then roast
with low and high airflow to observe the changes. Similarly,
with drum speed, try one with a significantly low drum speed
and one with a high drum speed and see how the coffee
roasts differently.
What we’re looking for is not necessarily a change in
taste—remember, we bought cheap coffee so we wouldn’t
mind ruining it with these experiments. Instead, we
are watching the effects on the rate of change/rise and
the overall time it takes the coffee to roast to the same
temperature. If the rate of change is higher and the terminal
temperature is reached in less time, the heat transfer to the
beans was more significant. If the rate of change is lower
and the overall time to terminal temperature is longer, the
heat transfer was less effective. I would highly recommend
exploring air speed (use a damper if a variable-speed fan is
not available), drum speed and charge settings. This will help
you discover how to set up roasts to accomplish your goals.
CONTINUED ON PAGE 44
42 May | J u n e 2 0 18 43HEAT AND THE ROASTING MACHINE | continued
Hoos recommends testing the variables on your own roasting
machine using inexpensive coffee you don’t mind wasting in the name
of scientific exploration. | Photos courtesy of the Specialty Coffee
Association
The TakeAway
As roasters, we work in an intuitive yet highly complex
field. Understanding how your roaster is controlled is
absolutely essential to properly roast coffee and/or design
roast profiles. Each of us must determine our own setup
regarding convection/conduction, heat application controls
and temperature measurement, even if we are working
on the same make and model of coffee roaster. This is an
ongoing area of research for the SCA, which now—as a
global association—has a greater base for funding and
implementing research projects. While that research
is in motion, the best thing you can do is take the time
to understand your own machine and exhaust setup.
Experiment, document and synthesize. Keep an open mind,
think critically—and have fun exploring your machine.
ROB HOOS is director of coffee at Nossa Familia Coffee
in Portland, Oregon. He is the lead consultant for Rob Hoos
Coffee Consulting (hoos.coffee) and author of Modulating the
Flavor Profile of Coffee: One Roaster’s Manifesto. Hoos is a
former member of the Roasters Guild Executive Council and a
specialized lead instructor, subject matter expert and content
contributor for the SCA.
JIM BRADY is a respected specialty coffee professional
and educator. For nearly 20 years, Brady has been an active
volunteer for the Specialty Coffee Association of America/
SCA and the Roasters Guild, serving as the instructor mentor
at Roasters Guild Retreats and as a member of the Roasters
Guild Education Committee. He is a specialized lead instructor/
authorized SCA trainer. He can be found roasting coffee at
Keurig Green Mountain Coffee in Knoxville, Tennessee, or
touring the country with his wife, Charmaine, looking for the
most delicious cup of coffee available.
44 May | J u n e 2 0 18 4546 May | J u n e 2 0 18 47
r o sc op y
p ce t
S I L L U M I N A T E D
A PRACTICAL APPROACH
TO DETERMINING
ROAST DEVELOPMENT
B Y C A R L S TA U B A N D S P E N C E R T U R E R
R
OASTING COFFEE is a culinary endeavor. As with all cooking methods,
manipulating temperature and energy during the process significantly
affects the outcome, specifically the time required to reach the desired
degree of “doneness,” the aroma, the flavor and, in the case of coffee, even
solubility.
In the early days of roasting, the only technique for determining degree
of roast development was to observe appearance, aroma and flavor. This
remains true for coffee roasters who lack scientific measuring devices.
While aroma and flavor will always be of greatest importance, advances in
technology brought about vision-based instrumentation that could measure
roast development by quantifying its lightness/darkness. This enhanced both
the resolution and repeatability of the appearance analysis component.
CONTINUED ON PAGE 50
Caption
Photo courtesy of
the Specialty Coffee
Association (SCA)
48 May | J u n e 2 0 18 49S P E C T R O S C O P Y I L L U M I N AT E D | A Practical Approach to Determining Roast Development | continued
Accuracy improved further with advances in vision-
COLOR MEASUREMENT Figure 1. PERCEIVED COLOR
based analytical equipment, which allowed for complex
color measurement that could quantify both chromaticity
(the quality of color, regardless of brightness)
and saturation (intensity). But as a more thorough Equipment designed to measure and quantify color operate in the
understanding of the chemical complexity of coffee visible, or VIS, spectrum. The visible spectrum is a narrow section
evolved, it revealed that vision-based measurements to of the electromagnetic spectrum and covers wavelengths from
classify roast suffer inaccuracy relative to the developed 380 nm (far blue) to 720 nm (far red). Because human vision is
organic chemistry responsible for coffee aroma and subjective, describing color is as complicated and challenging as
flavor. This is because, during the roasting process, describing the flavor of coffee. The perception of color—what we
the changes to color relative to the changes to organic “see”—is affected by several factors: The composite of wavelengths Image courtesy of ViewSonic (viewsonic.com)
chemistry are somewhat loosely related. Simply stated, it of the light source illuminating the item being observed, the surface
is possible to have two coffee samples roasted to exactly geometry and the size of the object being observed all change
A M O R E A C C U R AT E
the same “color” that present with a noticeably different what we perceive as color.
ANALYSIS: SPECTROSCOPY
roast development in the cup. There are several industry and scientific standards for defining
The two most recognized industry standards for perceived color, as well as for measuring and quantifying it.
measuring coffee roast development are numerical Color perceived by either an individual or an analyzer is actually
scores for cup characteristics and Agtron scores for roast made up of the components of the illuminating energy that are Roasted coffee contains more than 860 constituents. The most
classification. When those numbers are provided, coffee reflected, which is an inverse function of how the item absorbs the accurate method for classifying roast would be based on a
professionals quickly recognize their meaning and have illuminating energy. We can see the particular color of an object composite analysis of the chemical changes of all of those
definite expectations for roast development and cup only if that color exists in the illuminating light source. That is true constituents. While the technology for that type of analysis exists
Color analysis is an important component in determining roast development. | Photo
courtesy of Coffee Enterprises quality. for both humans and analytical equipment. (See Figure 1, right.) CONTINUED ON PAGE 52
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Using ground samples for color measurement is recommended as
they represent an integration of chemistry from the outside surface to
the center of the bean, a homogenous mixture that will best correlate
to the cup. | Photo courtesy of Agtron
(one being mass spectrometry, an analytical technique that
measures the mass-to-charge ratio of ions to identify and
quantify molecules in simple and complex mixtures), the
equipment is expensive and the complexity and amount
of data generated by coffee would require a high level
of expertise to unravel—not a simple or cost-effective
proposition for most coffee roasters.
A practical alternative for accurately determining roast
development based on chemical changes is an abbreviated
spectral analysis that focuses on a smaller compound group
known to progress during the roasting process in direct
relation to changes to the composite group of constituents.
Agtron roast analyzers employ spectroscopy to do exactly
that, utilizing specific wavelengths of near-infrared energy
outside the visible spectrum to accurately evaluate changes
to a group of compounds called quinones. Why quinones?
During roasting, quinones change in a predictable manner
relative to the evolution of the collective organic chemistry.
The changes occurring to quinones are quantifiable and
relate directly and accurately to changes occurring to the
es s en t i a l o n li n e volatiles associated with cup aromatics and flavor. Quinones
are also fairly easy targets for abridged spectroscopy.
r ea d i n g fo r Agtron roast analyzers produce a single number score
for a tested sample that is easy to understand: The lower the
s p ec i a lty c o ffe e number, the darker the roast development. Agtron numerical
p ro fes s i o n a ls test results, in combination with sensory evaluation, aid in
comparing multiple products for trend analysis, character
differences and consistency. The high analytical resolution
www.dailycoffeenews.com
enables the measurement of small changes in roast
development that may be missed by visual inspection.
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C O L O R C L A S S I F I C AT I O N T I L E S
The Roast Color Classification System tiles sold by the SCA reference the Agtron gourmet
scale. | Photo courtesy of SCA
UNITS OF MEASUREMENT
Understanding the meaning of the Agtron number begins with recognizing its
units of measurement. There are two Agtron coffee roast classification scales, each
developed to answer the specific needs of different types of roasters:
AGTRON COMMERCIAL SCALE is the original roast classification scale, and
was developed for large commercial roasters who also need to evaluate soluble
coffee in its dehydrated form. Commercial scale scores are presented as 0 to 100,
dark to light. Over time, this scale has been embraced by many other measuring
devices as a primary scale to be used for measuring roast development.
AGTRON GOURMET SCALE was later developed for specialty roasters who
were interested in a higher-resolution analysis than that offered by the commercial
scale. The higher-resolution scale of 0 to 133, still dark to light, sees a larger
numerical difference between two samples compared to the commercial scale.
Both scales use the same low reference point of 0.0, a number that correlates
to pure carbon, which is devoid of aroma and flavor. At the top end of the scale, a
sample that reads 100.0 on the commercial scale would read 133.0 on the gourmet
scale. The Roast Color Classification System tiles sold by the Specialty Coffee
Association (SCA) reference the Agtron gourmet scale. (See photos, above and
on page 48.) For example, a gourmet scale 55.0 chemistry score measured on an
CONTINUED ON PAGE 56
54 May | J u n e 2 0 18 55S P E C T R O S C O P Y I L L U M I N AT E D | A Practical Approach to Determining Roast Development | continued
Agtron analyzer is the roast development
ABOUT distributed throughout the entire bean measure of quality is in the cup. With all and other factors should always be quantified
approximated by the SCA/Agtron color
COMMERCIAL SCORE =
AGTRON READINGS structure. Ground samples represent other factors the same, different roasting using measuring tools and qualified through
tile No. 55. (Note: Analyzer roast score an integration of chemistry from the strategies will produce different results, sensory analysis. An honest criticism of one’s
resolution is ±0.1 while the best resolution (Gourmet Score +1.528) x 0.74294 outside surface to the center of the bean, and some will be better than others. Highly own work is essential to progress. Technology
achievable with a color tile under a homogenous mixture that will best skilled coffee roasters embrace both craft is just one component in the roaster’s toolbox.
GOURMET SCORE = The Agtron gourmet scale is based on two
controlled observation conditions is ±5.0.) correlate to the cup. With whole-bean and science. They are experimentalists and In the foreseeable future, roasting will remain
(Commercial Score x 1.346) – 1.528 reference points. A ground sample with a
The following equations can be used samples, only the outer surface, which continually strive to improve their skill set a balance between art and science.
gourmet reading of 3.0 would indicate the
to convert scores between the commercial represents a small and segregated and the quality of their coffee. Manipulating CONTINUED ON PAGE 58
thermal reduction of nearly 100 percent
and gourmet scales: portion of the resultant chemistry, will be the blend, the roasting process, the grind
of the organic chemistry into carbon,
analyzed. Also, the surface geometry of
and would be devoid of coffee aromatics
whole beans varies from sample to sample,
and flavors. It would be unrecognizable
which will introduce a measurement
as coffee. A ground sample with a
variable.
gourmet reading of approximately 133.0
would create a beverage with some of
the characteristics associated with an T H E PA L AT E
extremely light-roasted coffee, but would VERSUS ANALYZER
not be considered developed enough to RESOLUTION
be viable as a consumer product. It could,
however, be considered a sensory “break-
point,” where the quintessential aromas When defining a sensory profile for
and flavors associated with roasted coffee a given roast, a window of tolerance
are beginning to be perceivable. for the upper and lower limits of roast
The coffee industry has many development that maintains that profile
descriptors to identify roast levels. Often, must be specified. The minimum and
the generic adjectives used for dark, maximum roast specification also must
medium and light are based on each be within the controllable limits of
company’s perspectives of product the roasting equipment and the roast
quality, character and marketing. equipment operator.
For example, what is dark? Can you Differences in roast classifications
describe the difference between rust, are not equally sensed at all roast
bronze and amber? For this reason, developments. The constituent changes
utilizing a measuring device with that occur during the roasting process at
sufficient resolution and sensitivity to very light and very dark roasts are more
provide numerical roast classification chemically transitional and, as such, are
data for accurately controlling product more perceivable than those that occur
specifications is important. The units of in the middle of the development range.
measurement and the analytical scale also For example, a cupper may be able to
must be identified and industry-accepted detect changes at measured increments
standards in order for analysis results of 1.0 point for very dark or very light
to correlate and be recognized between roasts. In the middle of the roast scale, a
laboratories and roasting locations, or change may not be perceivable until it is a
from coffee supplier to customer. 2.5-point or greater measured difference.
E X P E R I M E N TAT I O N
W H AT T O M E A S U R E A N D T H E PA L AT E
While both whole-bean and ground
Coffee is a beverage intended for human
coffee easily can be measured for roast
consumption. Ultimately, our consumers
development, in our judgment using
judge what they prefer by their comments
ground sample scores provides the best
and purchasing behavior. Even by
reference for quality control. Why? The
applying the best technology to the
chemistry developed is not uniformly
roasting operation, the most important
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There are several industry and scientific standards for defining
perceived color, as well as for measuring and quantifying it.
Photo courtesy of Coffee Enterprises
GOOD
ANALYTICAL PRACTICE
There are three key components to any process control
program: having the appropriate equipment, knowing how
and when to use the equipment, and understanding the
results provided by the equipment.
Coffee roast development can be evaluated by the
human eye, but since visual inspection does not have the
same accuracy as a scientific measuring tool and is subject
to many perception variables, it is not suggested as the right
tool for product development or quality control.
Every tool in the tool chest or device on the laboratory
counter has an intended use and specific operational
instructions. Best practices for analytical equipment
operations are techniques and processes provided by
the manufacturer and industry professionals because of
the results achieved. The practices described below, or
those determined by each individual company or product
specification, should be followed consistently when results
are to be compared. When testing techniques are changed,
the measured results may change, rendering the data
unusable for comparisons with other testing techniques.
CONTINUED ON PAGE 60
58 May | J u n e 2 0 18 59You can also read
