R U L I N G T H E R O A S T
IMAGINE THAT consumers and specialty coffee aficionados around North America suddenly
refused to purchase dark, over-roasted coffee beans and began to demand that their local
coffeehouse offer a lightly-roasted, vibrant tasting, easy-to-digest coffee. Would you be able to
handle the challenge of creating the perfect light roast?
Of course, this is a hypothetical question. Dark-roasted beans enjoy such massive popularity
among coffee consumers that it is hard to imagine coffee drinkers spontaneously protesting
against the trend. For some reason, roasting dark seems to keep coffeehouses everywhere, from
the boardwalk beach cafés in San Diego to the rainy streets of Maine, in its tight grip.
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July | August 2004 31
Create the Perfect Light Roast
B Y W I L L E M J . B OOT
p h o t o s by k e n t h a n s o n
Lighten Up
RULING THE ROAST: LIGHTEN UP (continued)
Just ask small- to medium-sized roasters about the “why’s” of
their dark roasting style, and they will simply answer “because
my customers want it,” usually followed by an explanation that
lighter-roasted beans offer a more pronounced acidity, which is
not preferred by most of today’s coffee consumers.
That said, let’s pretend for a moment that consumers
suddenly started calling for a lighter roast. Would roasters be
ready to handle the challenge? Frankly, I don’t know. With the
grand popularity of dark-roasted coffees, the roasting community
seems to have lost some of its finesse. Because too many roasting
companies simply copy the roasting styles of some of the big
players, there seems to be only a handful of companies that dare
to roast any of their beans lighter than Agtron 55 (M-Basic),
considered in some European countries to be a very normal
roasting color for drip filter products. In Northern Italy, many
roasting companies apply the same degree to roasting espresso
beans, just up to the very first start of the second crack.
So what’s the big deal about roasting dark? Why should we
even have to consider a light roast when the average consumer
generally prefers the sweetness and potentially creamy finish
of a well-crafted dark roast? Why not stick to the play-it-safe
scenario and try to do what the average customer wants?
The answer is not simple. First of all, I believe that most
dark-roasted coffees lack brightness, sweetness and often have
cardboard, paper-like flavors, especially after the brewed coffee
has been kept for more than 10 minutes. Secondly, I believe thatlighter roast colors, such as those shown in the pictures
of the El Salvador peaberry bean and the Colombia
Armenia bean (both Agtron 58 to 60), generally offer
a much more complex cup profile than the same
coffees roasted to a darker degree, like Agtron 40 or
lower. Additionally, there are some other advantages
of roasting light, like a longer shelf life, less emissions
during roasting and a lower risk of roaster fires.
However, roasting coffee as light as the pictures
indicate is not easy; the roaster needs to follow certain
steps to ensure that the flavor profile of the coffee
is sufficiently developed, without creating sour,
astringent or malty notes, which can potentially be
predominant with under-roasted coffee beans. The
solution to developing proper profiles for lighterroasted
coffee beans is to investigate with each coffee
bean type the appropriate time-temperature pattern.
In the case of the Nicaragua coffee beans shown on
the following pages, we applied a roasting style with
moderate heat supply throughout the roast, which
resulted in a gradual increase of bean temperature.
So, what’s the secret to creating perfect-tasting
light roasts? Are you expecting me to reveal a longhidden
family secret that will propel your business
straight into the ranks of light-roast fame and fortune?Hardly, but that’s okay because you don’t need an ancient
roasting secret. Roasting light can be as easy as preparing a
medium-rare steak. Or as cooking pasta al dente, which gives
the pasta a pleasant bite, soft mouthfeel and makes your guest
grateful at the same time.
Let’s assume we have just purchased some bags of
Nicaraguan coffee in the most recent Cup of Excellence
auction. Furthermore, we have decided to roast the Nicaraguan
beans light enough so that the roast with its inevitable
caramelization will not mask the coffee’s flavor profile. By
following a light roasting protocol, we will attempt to preserve
the medium-toned acidity and apricot-like aftertaste of these
precious Nicaraguan beans. At the same time, we must take
into account the semi-hard bean structure of this coffee,
which requires moderate energy supply during a major part
of the roast cycle.
Seeing the Light
Are you ready? Let’s start a light roast. Make sure that the
roasting machine is fully preheated for at least 10 to 15
minutes. Next, we will determine our charging temperature,
which should be not too high for this coffee, otherwise these
medium-hard beans might tip or scorch. Upon charging,transformation is occurring—the beans are literally
soaking up the heat passing through the roasting drum.
The free moisture that is contained in the cell structure
of the beans is heating up and will eventually start
boiling and evaporating. Now, look at picture A. The
roast process is 3–4 minutes underway, and the color
of the beans will slowly start turning a golden brown.
If you pulled a small sample from the roasting drum
with the trier, you would smell a floral, sweet, almost
fresh bread-like aroma. From this moment on, it is
important to watch the increase in bean temperature.
By the sixth or seventh minute, the coffee develops a
more brownish color and the beans start expanding. A
hint of coffee aroma starts to emerge from the coffee
and the first crack gets closer. As picture B. shows, the
color approximates hazelnut brown and the surface of
the beans is quite smooth.
These Nicaraguan coffee beans can be classified
as semi-hard beans, grown at an elevation of
approximately 1,250 meters, which causes the beans
to look quite even at this stage in the roast. Highergrown
beans—1,400 meters and up—will have a
different appearance in this stage, with a rough surface
and an uneven color development.
As the roasting graph indicates (the letters on the graph
correspond to the pictures), the roastmaster has to roast
prudently to ensure a gradual increase in bean temperature.
The best way to accomplish this is by lowering the heat supply
to such a degree that the beans will continue roasting gradually
and slowly, which is essential for light roasting styles. At the
start of the first crack, heat inside the coffee beans becomes
exothermic, which causes them to generate heat. Because
roasting too fast can produce sour, astringent and malty roasting
taints, the roastmaster should lower the heat supply on time to
stay in control of the process.
When the first crack starts, listen to the speed of the cracks.
The faster you can hear one crack after another, the higher the
bean temperature is at this stage. If you feel that it’s going toofast, reduce heat supply; if it’s going too slow, increase heat
supply gradually. Picture C. shows the color of the beans
immediately after the first crack (9–10 minutes roasting),
and picture D. displays the color about one minute later. As
we can see, there is a marginal difference in color between
stage C and D. This is exactly what we are trying to
accomplish in this light roasting style; by roasting prudently,
we realize a gradual development of the coffee’s flavor
profile without unnecessarily stalling the process. After
stage D, it is up to the roaster to decide how much time to
prolong the roasting process; fundamentally and literally,
this is a matter of taste. With a roasting color of Agtron 58 to
60, the Nicaraguan coffee described here tasted delightfully
complex, with a subtle medium-toned acidity and—as I
hoped for—a delicious apricot-like aftertaste.
Hopefully, these tips can inspire roasters throughout
the world to use light roasts as a tool to unveil the flavor
profile rather than to mask it.