History of the coffee bean

INTRODUCTION

Coffee, common name for any of a genus of evergreen trees of the madder family, and also for their seeds (beans) and for the beverage made from them. Of the 40 species of the genus, only 3 are commercially important: arabica or Arabian, robusta or Congo, and Liberian. The shrub or small tree, 4.6 to 6 m (15 to 20 ft) high at maturity, bears shiny green, oval leaves that persist for three to five years and white, fragrant flowers that bloom for only a few days. During the six or seven months after the appearance of the flower, the fruit develops, changing from light green to red and, ultimately, when fully ripe and ready for picking, to deep crimson. The mature fruit, which resembles a cherry, grows in clusters attached to the branches by very short stems, and it usually contains two seeds, or beans, surrounded by a sweet pulp.
The coffee species are indigenous to Africa and adjacent islands, but have been introduced elsewhere. Today coffee grows well on the islands of Java, Sumatra, and Papua New Guinea, and in the Caribbean, Africa, Arabia, India, and South and Central America. The Americas, where arabica coffee is grown, produce approximately two thirds of the world's supply.
 

PRODUCTION

The soil in which coffee is grown must be rich, moist, and absorbent enough to accept water readily, but sufficiently loose to allow rapid drainage of excess water. The best soil is composed of leaf mould, other organic matter, and disintegrated volcanic rock. Although coffee trees are damaged easily by frost, they are cultivated in cooler regions that are prone to frost. The growing temperatures range from 13° to 26° C (55° to 80° F). Altitudes of coffee plantations range from sea level to the tropical frost level, about 1,800 m (6,000 ft). Robusta coffee and Liberian coffee grow best at altitudes below 900 m (3,000 ft); arabica coffee flourishes at the higher altitudes. The seeds are planted directly in the field or in specially prepared nurseries. In the latter case, selected young plants are transplanted later to the fields. Commercial fertilizers are used extensively to promote the growth of stronger, healthier trees with greater yields. Intercropping with nitrogen-fixing species (seeNitrogen Cycle), and shading with tall species, which provide leaf litter, are practised in various parts of the coffee-growing world. Both the trees and the fruit are subject to insect infestation and microbial diseases, which may be controlled by spraying and proper agricultural management. In the 1990s the use of integrated pest management and various environmentally aware methods have increased. Various hybrids, some of which are disease-resistant, have been developed, and traditional methods of selection are being replaced by genetic-engineering techniques to incorporate commercially useful traits, such as dwarf habit, disease resistance, or the absence of caffeine.
 

Harvesting The coffee tree produces its first full crop when it is about five years old. Thereafter it produces consistently for 15 or 20 years with careful pruning and good husbandry. Some trees yield 0.9 to 1.3 kg (2 to 3 lb) of marketable beans annually, but 0.45 kg (1 lb) is considered an average annual yield. Two methods of harvesting are used. One is based on selective picking; the other involves shaking the tree and stripping the fruit. In some areas mechanical harvesting has been introduced to do this. Beans picked by the first technique are generally processed, if water is available, by the so-called wet method, in which the beans are softened in water, de-pulped mechanically, fermented in large tanks, washed again, and finally dried in the open or in heated, rotating cylinders. This method can generate serious water pollution problems and considerable efforts are being made to convert the pulp to commercially valuable animal feed or mulch. The so-called dry method, used generally for beans harvested by the second technique, entails only drying the beans and removing the outer coverings. In either case the final product, called green coffee, is sorted by hand or machine to remove defective beans and extraneous material, and is then graded according to size, and sometimes colour, using electronic equipment.
 

Commercial Crops The major types of commercial coffee are the arabicas and the robustas. Arabicas are produced mainly in the Americas and East Africa and are usually wet processed, except those from Brazil. The dry-processed beans are described as "Brazils", and the wet-processed arabicas are generally referred to as "milds". Robustas are produced mostly in west Africa and Asia and are mostly dry processed, although wet-processed robustas are found in small quantities. The Brazils consist principally of Santos, Paraná, and Rio, named after the ports from which they are shipped. Milds are identified by the names of countries or districts in which they are grown, such as Medellín, Armenia, and Manizales coffees from Colombia. Robustas and other arabicas are similarly identified.
Usually several varieties of green coffee are blended and roasted together to produce the tastes, aromas, and flavours popular with coffee drinkers. As a rule the beans are heated in rotating, horizontal drums that provide a tumbling action to prevent uneven heating or scorching. Until the mid-1980s the temperatures for roasting ranged from about 193° C (380° F) for a light roast, through about 205° C (400° F) for a medium roast, to about 218° C (425° F) for a dark roast. The roasted beans are cooled rapidly. In the producing and consuming countries, the major roasters have moved to higher roasting temperatures and more rapid throughput, which is more energy efficient. This process has been criticized by some for producing a more bitter beverage as the surface of the bean is severely heated while the interior of the bean receives less severe heat. A very slow-roasting process has also been developed, which exploits cheap waste materials for fuel. Roasted coffee may be packaged and shipped to shops, which grind it for the customers on purchase, or it may be ground in plate- or roller-type grinding mills before shipment.
Ground coffee loses its unique flavour within about a week unless it is specially packaged. Plastic-and-paper combinations are popular packagings that afford protection to freshly roasted and ground coffee. Hermetically sealed vacuum, or pressure, cans keep coffee fresh for up to three years if unopened. Once opened, exposure to oxygen and moisture in the air accelerate the deterioration, but this can be retarded by sealing tightly and chilling in a refrigerator. Whole roasted beans contain a lot of carbon dioxide, which provides an inert atmosphere and acts as a preservative for the delicate aroma. Ground roasted beans contain less, but still a significant amount.
 

CHARACTERISTICS

Coffee contains a complex mixture of chemical components, some of which are not affected by roasting. Other compounds, particularly those related to the aroma, are produced by partial destruction of the green bean during roasting. Chemicals extracted by hot water are classified as non-volatile taste components and volatile aroma components. Important non-volatiles are caffeine, trigonelline, chlorogenic acids, amino acids, carbohydrates, and minerals. Important volatiles are organic acids, aldehydes, ketones, esters, amines, and thiols (sulphur compounds also known as mercaptans). The principal physiological effects of coffee are produced by caffeine, an alkaloid that acts as a mild stimulant.
In recent years controversy has arisen over the possibly harmful effects of coffee. With the modest consumption of coffee, caffeine is of little concern to most, and any effects are relatively short-lived. There has been concern, however, that heavy consumption during pregnancy may harm the foetus.
During the 1990s a fat-soluble diterpene called cafestol, for which coffee is the only known source, was identified as the substance that causes a reversible increase in cholesterol. Diterpene only enters coffee when it is prepared by boiling ground beans in water as commonly practised in France, Italy, and Scandinavia. It does not enter filtered coffee or instant coffee powder. The risk factors for heart disease in humans, however, remain uncertain.
Green beans contain trigonelline, which, during roasting, is partially converted to niacin, one of the B vitamins. In some areas of the world, the coffee drink may be a very important source of this vitamin. Unless sugar, milk, or cream is added, coffee is low in calories.
 

FORMS OF COFFEE

Instant Coffee Instant or soluble coffee is an important product of the coffee industry. At one time it was manufactured only in the consuming countries, but there are now large commercial plants in the coffee-growing countries. In its manufacture an extract is prepared by mixing coarsely ground, roasted coffee with hot water under pressure. The extract is concentrated and dried by various methods, including the use of spray driers. In freeze-dried coffee the concentrated coffee extract is frozen, and the water is removed by sublimation under high vacuum. The product is packed under vacuum in sealed jars or in cans. Only the addition of hot water is required to make the beverage. The extraction rate-that is, the amount of instant powder that can be made from a given amount of green bean-is controlled by legislation.
 

Decaffeinated Coffee Caffeine can be removed from coffee by treating the green beans with an ester or chlorinated hydrocarbon solvents. The decaffeinated beans are roasted by ordinary procedures after the removal of the solvents. More recently, supercritical carbon dioxide (carbon dioxide under great pressure) has been used commercially in Europe and the United States to remove the caffeine. This process is attractive as it leaves no solvent residues in the extracted beans, but it has the disadvantage of being more expensive. Decaffeinated coffee is used by people who prefer to avoid the caffeine present in ordinary coffee.
 

Coffee Substitutes The use of substitutes for coffee is limited and controlled by legislation. The most important substitute is roasted chicory, although chicory is usually used as an extender. Roasted dandelion root, figs, and extracts of various cereals are also used. In most countries, the addition of chicory or any other substance must be clearly stated on the brand label.
 

HISTORY

Exactly where and when coffee was first cultivated is not known, but some authorities believe that it was grown initially in Arabia near the Red Sea in about AD 675. Coffee cultivation was rare until the 15th and 16th centuries, when extensive planting of the tree occurred in the Yemen region of Arabia. The consumption of coffee increased in Europe during the 17th century, prompting the Dutch to cultivate it in their colonies. In 1714 the French succeeded in taking a live cutting of a coffee tree to the island of Martinique in the Caribbean. This single plant was the genesis of the great coffee plantations of Latin America.
Because of the economic importance of coffee exports, a number of Latin American countries made arrangements before World War II to allocate export quotas so that each country would be assured a certain share of the United States coffee market. The first coffee quota agreement was arranged in 1940 and was administered by an Inter-American Coffee Board. The idea of establishing coffee export quotas on a worldwide basis was adopted in 1962, when an International Coffee Agreement was negotiated by the UN. During the five-year period in which this agreement was in effect, 41 exporting countries and 25 importing countries acceded to its terms. The agreement was renegotiated in 1968, 1976, and 1983. Participating nations failed to sign a new pact by the end of 1997.
Scientific classification: Coffee makes up the genus Coffea of the family Rubiaceae. Arabica or Arabian coffee is classified as Coffea arabica, robusta or Congo coffee as Coffea canephora, and Liberian coffee as Coffea liberica or Coffea excelsoides.



 

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