What is Coffee

The coffee we drink comes from the roasted seed of a small cherry like fruit.  The fruit grows on a tropical evergreen tree called by its botanical name Coffea arabica.  There are over one hundred species of coffee tree but the arabica species is the most widely grown and accounts for three quarters of the world's yearly production.  All the coffee species are native to equatorial Africa and some islands in the Indian Ocean such as Madagascar and the Reunion Islands.  Like so many other plants the coffee plant also has a number of coffee varieties.

Another coffee species is Coffea canephora and accounts for about one quarter of the world's yearly production.  This species is usually called by the name robusta.  It originated in the low lands of equatorial Africa and does not possess the flavor characteristics of arabica coffee and is generally used in blends to reduce cost. 

Since coffee is a tropical evergreen plant it can only be grown in areas free of frost or freeze.  For this reason almost all commercially grown coffee occurs in the tropics between the Tropic of Capricorn and the Tropic of Cancer.  Each year the coffee tree blossoms with each blossom becoming a single coffee cherry.  This blossoming usually occurs during the rainy season but may occur over a period of weeks or months depending on the local climate.  In some regions the coffee tree may have flowering blossoms, green unripe cherries and ripe cherries on it at the same time. 

The highest quality coffees are of the arabica species that are grown in rich volcanic soil at altitudes of between 4000 and 6000 feet.  Ideal growing conditions are where daily high temperatures are in the 70's and the nightly low temperatures are in the 60's.  Growing conditions at high altitude slows the maturation process producing a more dense flavorful bean with higher acidity.  The maturing of the cherry takes between seven to nine months. 

Inside each coffee cherry are two seeds.  These seeds will become the coffee bean and are the inner most part of the fruit.  These two little flat sided seeds contain over one thousand flavoring compounds that produce the incredible taste and aroma experienced in a cup of coffee.  Surrounding the seed is a very thin covering called the silver skin.  Surrounding the silver skin is the parchment covering.  The coffee cherry has a sweet pulp region surrounding the parchment but the coffee cherry pulp is only a small part of the fruit and the pulp is discarded during the processing of coffee.  The pulp is covered by the outside skin of the cherry. 

In some cases the coffee cherry will develop only one seed inside.  In some growing regions as much as ten percent of the harvested cherries will develop this way.  As the seed matures it will curl around on itself producing a shape that resembles a tiny blunt ended football.  This is because the missing seed would normally prevent this from happening. In some countries these single seeds are sorted out of the otherwise normal seeds to be sold as a high valued coffee bean called the peaberry.  In the past the peaberry was considered to be a defect and was sorted out and discarded.  Today the general consensus is that the peaberry is highly prized for its more intense and unique flavor profile than its brothers, and therefore is much sought after.

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