Coffee beans are the seeds of the coffee "cherry"; two seeds normally grow within
each cherry. On the tree, the beans are covered by the silverskin (a vestigial remainder
of the fruit's development, also called the spermoderm). The silverskin is covered
by a parchment skin (the endocarp), which is covered by a slimy layer (the parenchyma),
surrounded by a thin layer of pulp (the mesocarp), all covered by an outer skin (the
exocarp). These layers must be removed prior to roasting, though some silverskin
often remains attached.
Arabica and robusta
All coffee beans come from plants in the genus Coffea. Although there are thousands
of species of plants within this genus, with tremendous variance in size and shape,
only two are of commercial importance: Coffea arabica, and Coffea canephora, the
latter more commonly called robusta, after a prime variety. A third species, Coffea
liberica has found some localized production in Liberia, but it is of minor significance
in the global market.
Arabica is genetically distinct: it has four sets of chromosomes, whereas robusta,
and liberica each have two.
The taste of arabica beans differ between varieties and growing regions--the same
variety grown in different parts of the world will taste different. These taste notes
can be as varied as berries (blueberry is often particularly noted in Ethiopian Harrar),
earthy (a characteristic associated with Indian and Indonesian coffees,) citrus (common
with Central Americans), or chocolate.
On average, a robusta will be harsher. One importer likened a particularly bad origin
to dung, though very fine robustas can, potentially, compare favourably to a quality
arabica. Premium robustas are essentially reserved for espresso blends, where they
are primarly used to greatly improve the crema and to add a certain bite to the shot.
The difficulty is in finding an exceptional robusta; growers and processors are often
not willing to dedicate as much effort to robusta as they are to arabica, since the
only potential market is for those blends. Robustas are rarely sold straight; instead,
in addition to premium robustas used in espresso blends, poor quality robustas may
be added to freeze-dried coffees or to coffee-flavoured frozen drinks where the sugar
and cream overwhelm the off-notes. Robusta has notably more caffeine than arabica.
Jamaican Blue Mountain
Often used as a synonym for coffee excellence, Jamaican Blue Mountain refers to a
specific region on the island of Jamaica: the Blue Mountains, of which Blue Mountain
Peak is the highest point on Jamaica at 7,402 feet. Only coffee grown on certain
estates may be called "Blue Mountain": Wallenford, Mavis Bank, Silver Hill, and Moy
Hall registered the rights to call their product Blue Mountain, and Old Tavern Estate
was in recent years awarded the right to use the name. The sale, roasting, and export
of Blue Mountain coffee is strictly controlled by the Jamaican government and the
Coffee Industry Board
Why are some coffees aged?
Unroasted coffee beans that are properly stored will change their taste profile.
Acidity decreases and the perceived body deepens, while certain defects can become
less apparent. Those coffees given the appellation "aged" are usually held for a
number of years under carefully controlled conditions, and may have extraordinarily
rich bodies. However, some aged coffees simply taste old and flat. Make sure you
buy aged coffee from a reputable dealer who has sampled ("cupped") that particular
What's a monsooned coffee?
Monsooned coffees have been held in open-sided warehouses and exposed to the steady,
damp monsoon winds. In a matter of weeks, the beans yellow, and gain a flavour reminiscent
of, but distinct from aged coffees. By far the most common monsooned coffee is Indian
monsooned Malabar. Again, buy from a retailer who is personally familiar with the
particular batch of coffee you are considering purchasing. Monsooned coffee isn't
for everyone, but it should be sampled.