“Coffee
may be purchased by the packet, pound or cup, but weight (the quantity measure)
has value only insofar as it has acceptable flavor (the quality measure). Coffee has ONE
basic value: it gives pleasure and
satisfaction through flavor, aroma and desirable physiological and
psychological effects.”
Michael
Sivetz
I. A Brief History
The
most famous version of the origin of coffee goes like this: Once upon a time in the land of Arabia Felix,
Ethiopia,
Africa, lived a goatherd named Kaldi. Kaldi was a sober, responsible goatherd,
whose goats were also sober, if not responsible. One night Kaldi’s goats didn’t come home, and
in the morning he found them dancing in abandoned glee near a shiny,
dark-leaved shrub with red berries.
Kaldi soon determined that it was the red berries on the shiny,
dark-leaved shrub that caused their eccentric behavior, and it wasn’t long
before he was dancing, too.
Finally
a learned innam from a local monastery came by, sleepily, no doubt
on his way to prayer. He saw the goats
dancing, Kaldi dancing, and the shiny, dark-leaved shrub with the red
berries. Being of a more systematic turn
of mind than the goats or Kaldi, the learned innam subjected the red berries to various experimental
examinations, one of which involved parching and boiling. Soon neither the innam nor his fellows fell asleep at prayers, and the use of coffee
spread from monastery to monastery, throughout Arabia Felix, and from there to
the world. We never find out whether
Kaldi and his goats dropped dead from exhaustion and caffeine poisoning, or
learned to control their habit.
II. The Nature of Coffee
The
coffee plant is a shrub that belongs to the family Rubiaceae, genus
Coffea. Some dozens of species of the
genus Coffea are known, but only two are significant in economic terms: Coffea Arabica and Coffea canephora (also
known as Arabica and Robusta, respectively), being the only two that are
cultivated on a large scale. Each of
these two species comprises several varieties, some derived from natural
mutations and some the results of genetic engineering. Robusta coffees do not have the fragrance or
flavor of the best Arabica coffees but they are more resistant to disease and
grow at lower altitudes.
The
coffee plant grows in countries that lie beween the two Tropics, in zones where
there are no seasonal climatic changes:
there it is always summer or something between spring and summer. Plants are therefore evergreen and bear fruit
in a continuous cycle. Coffee plants are
no exception and lacking rising spring temperatures to prompt flowering, as is
the case with plants in our part of the world, they depend on rainfall to this
end. This means that following every
rainfall, after about two weeks the plant will flower: if it rains ten times in a year, the plant
will flower ten times. Therefore, if the
rainfall is distributed throughout the year, you find plants simultaneously
bearing flowers, ripening fruit and full ripe fruit.
After
the flowering period, which lasts only a few days, the ovary of the fertilized
flower rapidly develops into a fruit that is initially green in colour; by 6-10
weeks the berry has already reached its full size. During the final weeks the berries change
color, becoming first yellow and eventually bright red, with the exception of a
few varieties such as Bourbon whose ripe fruits are yellow.
One
interesting fact to remember about coffee:
Each coffee tree yields, on the average, one pound of beans per year.
III. Coffee Processing
Harvesting
is one of the most important factors in how coffee tastes. As has been stated, coffee berries do not always
ripen uniformly. Therefore, the
conscientious grower who wants to get a high price for his coffee will pick the
berries selectively; he will go over his trees again and again picking only
ripe berries. Where coffee is carelessly
harvested, the berries are stripped just once from the tree, ripe, unripe, and
overripe all together.
Once
it is picked, coffee can be prepared either by the “dry” method which produces what
is called “natural” coffee, or by the “wet” method, which produces “washed
coffee”. The “dry” method, which is the older, more primitive method, simply
involves drying the berries in the sun or in a mechanical dryer, and later
stripping the hard, shriveled husk off the bean, either by modern machine or
with a grindstone or mortar and pestle.
The
wet method removes most of the covering from the bean before it is dried. Since the moist bean is liable to damage if
treated roughly, the covering must be removed gingerly, layer by layer. First the skin and pulp are gently stripped
off by machine. This leaves the beans
covered with a sticky gluey substance, which if removed mechanically, would
damage the bean. Instead, the beans are
soaked, and natural enzymes literally digest or ferment this slimy layer off
the bean. This step is called
“fermentation.”
Next,
the coffee is gently washed, and finally dried, either by the sun in open
terraces, where it is continuously turned and stirred by workers, or in large
mechanical driers. This leaves a last
thin skin covering the bean, called the “parchment” or “pergamino.” Some coffee is sold and shipped in its
parchment cover but most often a last machine called a “huller” is used to
remove it before shipping. The huller is
also designed to polish the coffee, giving the flinty, dry beans a clean,
glossy look especially important to specialty roasters, who sell their coffee
in whole bean.
Wet
processed coffee is not necessarily better than dry-processed coffee. Wet processed coffees generally bring higher
prices in world markets. Such coffees
tend to be more finely flavored for several reasons: generally, the better coffees are prepared by
the more costly wet method; only ripe cherries are picked for preparation by
the wet method whereas coffee produced by the dry method often includes
immature and over-ripe cherries; also, allowing the beans to ferment for a
short time after the pulp has been removed is said to enhance the flavor. Processed with care, however, natural coffees
can be as good or better than washed coffee.
Dry
processed arabicas are often used as the base of espresso blends then enhanced
with wet processed Arabica for flavor and a small amount of robusta for
body. The wet processed Arabica must not
be used in too high a proportion for two reasons: their characteristic acidity is heightened in
the preparation of espresso coffee, and their consistency is often very hard
and tenacious; after grinding, the particles are still highly homogenous. To encourage the development of body in the
coffee it is better to have particles of different sizes in the ground coffee,
as occurs with the dry-processed arabicas.
IV. Roasting
Unroasted
coffee gives no clue as to what it might become. The beans do not have the characteristic
look, smell or taste of coffee. Most
people do not even recognize the contents of the freshly-imported bags.
Roasting
is simple in theory: The beans must be
heated, kept moving so they don’t burn or roast unevenly, and cooled when the
right moment has come to stop the roasting.
Coffee which is not roasted long enough or hot enough to bring out the
oil will have a pasty, nutty, or bread-like flavor. Coffee which is roasted too long or at too
high a temperature will be thin-bodied, burned, and industrial-flavored; very
badly burned coffee will taste like old sneakers left on the radiator. Coffee roasted too long at too low a temperature
will have a baked flavor.
Most
roasting equipment uses a rotating drum with a heat source under it, usually a
gas flame. The rotating drum tumbles the
beans, very akin to a clothing dryer, assuring an even roast. The air temperature inside the drum is
usually controlled at about 500 degrees F; for the first five minutes, the bean
merely loses “free” moisture, moisture which is not bound up in the cellular
structure of the bean. Eventually,
however, the deep “bound” moisture begins to force its way out, expanding the
bean and producing a snapping or crackling noise. So far, the color of the bean has not
appreciably changed (it should be a light brown), and the oil has not been
volatilized. Then, when the interior
temperature of the bean reaches about 400 degrees F, the oil quite suddenly
begins developing; chemists call this process pyrolysis; it is marked visually
by a darkening in the color of the bean.
This
is the moment of truth for the coffee roaster, machine or human, because the
pyrolysis, or volatilization of the coffee essence, must be stopped at
precisely the right instant to obtain the flavor and roast desired. The beans cannot be allowed to cool of their
own accord, or they may over-roast. They
are quickly dumped into a metal box, where pyrolysis continues until “quenched”
with either cold air or a light spray of cold water.
Given
a good quality bean, roasting is probably the single most important factor
influencing the taste of coffee. The
significant variable is the length of time the coffee is roasted. The longer the roasting, the darker the
bean. The darker the bean, the more
tangy and bittersweet the flavor.
V. Variety of Roasts
As
we have learned, the roasting of coffee turns the beans brown; the longer
they’re roasted the darker they get.
Coffee roasted too light won’t have much of a coffee taste at all. Coffee can also be roasted so dark that it
tastes burnt. Between these two extremes
are a variety of roasts all tasting like coffee, each appealing to particular
tastes.
Below
is a chart of five different roast levels along with their common names and
characteristic tastes.
|
1
|
Light
brown; dry surface
|
Cinnamon
New
England
Light
|
Tastes
more like toasted grain than
coffee,
with distinct sour or acidic
tones.
|
|
2
|
Medium
brown, dry
Surface
|
Regular
American
Medium
high
Medium
Brown
|
For
an American the characteristic
Coffee
flavor; the grain flavor is gone;
A
definite acidy snap, but richer
Toned
and sweeter than 1.
|
|
3
|
Slightly
darker brown;
Patches
of oil on the
Surface
|
Light
French
High
Viennese
City
Full
city
|
A
slight, dark-roasted, bittersweet
Tang,
almost indistinguishable. Less
Acidy
snap than 2.
|
|
4
|
Dark
brown; oily
Surface
|
Italian;
Espresso;
European;
French;
After-dinner;
Continental;
Dark
|
A
definite bittersweet tang; All
Acidy
tones gone.
|
|
5
|
Very
dark brown, almost
Black;
very shiny, oily surface
|
Dark
French
French
Italian;
Heavy
|
Burned
or charcoal tones plus
The
bittersweet tang; all acidy tones gone.
|
The
overriding factor, in determining which roast to assign a specific coffee, is
which roast brings out the true varietal characteristics of said coffee. For example; dark roasting a high-grown Costa
Rican coffee will mask the bright acidity and clean cup character so prized in
high-quality Costa Ricans.
