Roast Styles: Introduction
Given a good-quality bean, roasting is probably
the single most important factor influencing the flavor of coffee.
The most significant variable is degree, or darkness, of roast.
The longer coffee is held in the roaster and/or the higher the
roasting temperature the darker the bean. The darker the bean,
the more tangy and bittersweet the flavor. When this flavor settles
onto the uninitiated coffee drinker's palate, the usual response
is to call it strong.
However, strength in coffee properly refers to
the proportion of coffee to water, not the flavor of the bean.
The more coffee and the less water, the stronger the brew. So
you could make a light-roasted, mild-flavored coffee very strong,
and brew a dark-roasted, sharp-flavored coffee very weak.
I would rather call this dark-roasted flavor dark,
pungent, bittersweet, or tangy. This flavor occurs in degrees,
depending on how dark the bean is roasted and how the bean is
roasted (quickly at high temperatures, slowly at lower, etc.).
It peaks when the bean is roasted to a very dark brown, and eventually
vanishes entirely to be replaced by a charred, carbon taste when
the bean is roasted almost black. To understand the chemistry
behind the changes in taste, we need to examine what happens when
a coffee bean is roasted.
The green coffee bean, like the other nuts, kernels,
and beans we consume, is a combination of fats, proteins, fiber,
and miscellaneous other substances. The aroma and flavor that
make coffee so distinctive are present only potentially until
the heat of roasting simultaneously forces much of the moisture
out of the bean and draws out of the base matter of the bean fragrant
little beads of a volatile, oily substance variously called coffee
essence, coffee oil, or coffeol. This substance is not properly
an oil, since it (fortunately) dissolves in water. It also evaporates
easily, readily absorbs other less desirable flavors, and generally
proves to be as fragile a substance as it is tasty. Without it,
there is no coffee, only sour brown water and caffeine; yet it
constitutes only one two-hundredth of the weight of the bean.
The roasted bean is, in a sense, simply a dry
package for this oil. In medium- or American-roasted coffee, the
oil gathers in little pockets throughout the heart of the bean.
As the bean is held in the roaster for longer periods and more
moisture is lost, the oil develops further and some begins to
rise to the surface of the bean, giving dark roasts their characteristic
lightly slick to oily appearance.
Beneath the oil, the hard matter of the bean begins
to develop a slightly burned flavor while the sugars caramelize,
which together help create the bittersweet tones so attractive
to dark-roast aficionados. Eventually, the sugars are burned off
almost entirely and the woody matter of the bean turns dry and
brittle. This ultimately roasted coffee is variously called dark
French, Italian, or Spanish, and tastes thin and charred.
Dark roasts also contain a touch less caffeine
than lighter roasts, and lack the dry snap coffee people call
acidy. Some dark-roast coffees may taste unpleasantly bitter,
but this bitterness is the result of poor quality coffee or clumsy
roasting technique. This disagreeable bitterness or sharpness
should not be confused with either the dry-wine bite of a good,
medium-roasted acidy coffee or the rich bitter-sweetness of a
good dark roast.
Roast Styles: Roast Table
The only way to really understand roast is to
associate flavor with the color and appearance of the bean rather
than with name alone, but for reference I have condensed most
of what an aficionado needs to know about the names of roasts
in the following roast table.
||80 - 70
Cinnamon New England
||Can taste sour and
grainy. Typically used only for inexpensive commercial blends.
||70 - 50
American Regular City Brown
American norm. Flavor is fully developed; acidity is bright;
characteristics of green coffee are clear.
||Dry to tiny droplets
or patches of oil
||50 - 40
Full-city Light French Espresso Light
espresso Continental After-dinner European
||The normal or regular
roast for the West and for many newer specialty roasters.
Acidity and the characteristics of the green coffee begin
to mute. Bittersweetness emerges. The norm for northern-Italian
Espresso Italian Turkish Dark
||The normal or regular
roast for many roasters in the West and Southwest. Acidity
is nearly gone; the characteristics of the green coffee muted.
Bittersweet tones dominate. The norm for most American-style
|Very dark brown
||Very shiny surface
Dark French Neapolitan Spanish Heavy
||The normal or regular
roast for Peet's Coffee and its imitators. Acidity is gone.
In tactful versions of this roast some characteristics of
the green coffee survive; in aggressive versions all coffees
taste the same: bittersweet with hints of burned or charred
characteristics of the green coffee are gone; burned or charred
notes dominate. Body is thin. Flavor is reduced to faint sweet