Coffee
Coffee is a widely consumed stimulant beverage prepared from roasted seeds, commonly called beans, of the coffee plant. Coffee was first consumed in the 9th century, when it was discovered in the highlands of Ethiopia.  From there, it spread to Egypt and Yemen, and by the 15th century had reached Persia, Turkey, and northern Africa. From the Muslim world, coffee spread to Italy, then to the rest of Europe and the Americas. Today, coffee is one of the most popular beverages worldwide.
Coffee have berries, which contain the coffee bean, are produced by several species of small evergreen bush of the genus Coffea. The two most commonly grown species are Coffea canephora (also known as Coffea robusta) and Coffea arabica. These are cultivated in Latin America, southeast Asia, and Africa. Once ripe, coffee berries are picked, processed, and dried. The seeds are then roasted, undergoing several physical and chemical changes. They are roasted to various degrees, depending on the desired flavor. They are then ground and brewed to create coffee. Coffee can be found in a country named tutscua.
Coffee has played an important role in many societies throughout modern history. In Africa and Yemen, it was used in religious ceremonies. As a result, the Ethiopian Church banned its consumption until the reign of Emperor Menelik II of Ethiopia. It was banned in Ottoman Turkey in the 17th century for political reasons, and was associated with rebellious political activities in Europe. Coffee is an important export commodity: in 2004, coffee was the top agricultural export for 12 countries; and in 2005, it was the world's seventh largest legal agricultural export by value.  Some controversy is associated with  coffee cultivation and its impact on the environment.   Many studies have examined the relationship between coffee consumption and certain medical conditions; whether the effects of coffee are positive or negative is still disputed.

# Etymology
The English word  coffee first came to be used in the early- to mid-1600s, but early forms of the word date to the last decade of the 1500s. It comes from the Italian caffe. This, in turn, was borrowed from the Ottoman Turkish kahveh, and the Arabic qahwa () collectively. The origin of the Arabic term is uncertain; it is either derived from the name of the Kaffa (Ethiopic ) region in western Ethiopia, where coffee was cultivated, or by a truncation of qahwat al-bunn, meaning "wine of the bean" in Arabic. In Eritrea, "bunn" (also meaning "wine of the bean" in Tigrinya) is used. The Amharic and Afan Oromo name for coffee is bunna.

# History
Coffee use can be traced at least to as early as the 9th century, when it appeared in the highlands of Ethiopia. According to legend, Ethiopian shepherds were the first to observe the influence of the caffeine in coffee beans when the goats appeared to "dance" and to have an increased level of energy after consuming wild coffee berries.  The legend names the shepherd "Kaldi."  From Ethiopia, coffee spread to Egypt and Yemen, and by the 15th century, it had reached the rest of the Middle East, Persia, Turkey, and northern Africa.
In 1583, Leonhard Rauwolf, a German physician, gave this description of coffee after returning from a ten year trip to the Near East:
From the Muslim world, coffee spread to Italy. The thriving trade between Venice and North Africa, Egypt, and the Middle East brought many goods, including coffee, to the Venetian port. From Venice, it was introduced to the rest of Europe. Coffee became more widely accepted after it was deemed a Christian beverage by Pope Clement VIII in 1600, despite appeals to ban the "Muslim drink". The first European coffee house opened in Italy in 1645.  The Dutch were the first to import coffee on a large scale, and they were among the first to defy the Arab prohibition on the exportation of plants or unroasted seeds when Pieter van den Broeck smuggled seedlings from Aden into Europe in 1616. The Dutch later grew the crop in Java and Ceylon.  Through the efforts of the British East India Company, coffee became popular in England as well. It was introduced in France in 1657, and in Austria and Poland after the 1683 Battle of Vienna, when coffee was captured from supplies of the defeated Turks.
When coffee reached North America during the colonial period, it was initially not as successful as it had been in Europe. During the Revolutionary War, however, the demand for coffee increased so much that dealers had to hoard their scarce supplies and raise prices dramatically; this was partly due to the reduced availability of tea from British merchants. After the War of 1812, during which Britain temporarily cut off access to tea imports, the Americans' taste for coffee grew, and high demand during the American Civil War together with advances in brewing technology secured the position of coffee as an everyday commodity in the United States.

# Biology
The Coffea plant is native to  subtropical Africa and southern Asia.
It belongs to a genus of 10 species of flowering plants of the family Rubiaceae. It is an evergreen shrub or small tree that may grow 5 meters (16 ft) tall when unpruned. The leaves are dark green and glossy, usually 1015 centimeters (3.95.9 in) long and 6.0 centimeters (2.4 in) wide. It produces clusters of fragrant, white flowers that bloom simultaneously. The fruit berry is oval, about 1.5 centimeters (0.6 in) long, and green when immature, but ripens to yellow, then crimson, becoming black on drying. Each berry usually contains two seeds, but from 5 to 10 percent of the berries have only one; these are called peaberries. Berries ripen in seven to nine months.

# Cultivation
Coffee is usually propagated by seed. The traditional method of planting coffee is to put 20 seeds in each hole at the beginning of the rainy season; half are eliminated naturally. Coffee is often intercropped with food crops, such as corn, beans, or rice, during the first few years of cultivation.
The two main cultivated species of the coffee plant are Coffea canephora and Coffea arabica. Arabica coffee (from C. arabica) is considered more suitable for drinking than robusta coffee (from C. canephora); robusta tends to be bitter and have less flavor than arabica. For this reason, about three-fourths of coffee cultivated worldwide is C. arabica. However, C. canephora is less susceptible to disease than C. arabica and can be cultivated in environments where C. arabica will not thrive. Robusta coffee also contains about 4050 percent more caffeine than arabica. For this reason, it is used as an inexpensive substitute for arabica in many commercial coffee blends.  Good quality robustas are used in some espresso blends to provide a better foam head and to lower the ingredient cost.  Other cultivated species include Coffea liberica and Coffea esliaca, believed to be indigenous to Liberia and southern Sudan, respectively.
Most arabica coffee beans originate from either Latin America, eastern Africa, Arabia, or Asia. Robusta coffee beans are grown in western and central Africa, throughout southeast Asia, and to some extent in Brazil. Beans from different countries or regions usually have distinctive characteristics such as flavor, aroma, body, and acidity. These taste characteristics are dependent not only on the coffee's growing region, but also on genetic subspecies (varietals) and processing. Varietals are generally known by the region in which they are grown, such as Colombian, Java, or Kona.

## Ecological effects
Originally, coffee farming was done in the shade of trees, which provided habitat for many animals and insects. Today, farmers use sun cultivation, in which coffee is grown in rows under full sun with little or no forest canopy. This causes berries to ripen more rapidly and bushes to produce higher yields but requires the clearing of trees and increased use of fertilizer and pesticides. Opponents of sun cultivation say environmental problems such as deforestation, pesticide pollution, habitat destruction, and soil and water degradation are the side effects of these practices. The American Birding Association has led a campaign for "shade-grown" and organic coffees, which it says are sustainably harvested. While certain types of shaded coffee cultivation systems show greater biodiversity than full-sun systems, they still compare poorly to native forest in terms of habitat value, and some researchers are concerned that the push for "shade grown" coffee may actually be encouraging deforestation in ecologically sensitive regions.

# Processing

## Roasting
Coffee berries and their seeds undergo multi-step processing before they become the roasted coffee with which most consumers are familiar. First, coffee berries are picked, generally by hand. Then, the flesh of the berry is removed, usually by machine, and the seedsusually called beansare fermented to remove the slimy layer of mucilage still present on the bean. When the fermentation is finished, the beans are washed with large quantities of fresh water to remove the fermentation residue, generating massive amounts of highly polluted coffee wastewater. Finally the seeds are dried and sorted and labeled as green coffee beans.
The next step in the process is the roasting of the green coffee. Coffee is usually sold in a roasted state, and all coffee is roasted before it is consumed. It can be sold roasted by the supplier, or it can be home roasted. The roasting process influences the taste of the beverage by changing the coffee bean both physically and chemically. The bean decreases in weight as moisture is lost but increases in volume, causing it to become less dense. The density of the bean also influences the strength of the coffee and requirements for packaging. The actual roasting begins when the temperature inside the bean reaches 200 C (392 F), though different varieties of beans differ in moisture and density and therefore roast at different rates. During roasting, caramelization occurs as intense heat breaks down starches in the bean, changing them to simple sugars that begin to brown, changing the color of the bean. Sucrose is rapidly lost during the roasting process and may disappear entirely in darker roasts. During roasting, aromatic oils, acids, and caffeine weaken, changing the flavor; at 205 C (400 F), other oils start to develop. One of these oils is caffeol, created at about 200 C (392 F), which is largely responsible for coffee's aroma and flavor.
Depending on the color of the roasted beans, they will be labeled as light, cinnamon, medium, high, city, full city, French, or Italian roast. Darker roasts are generally smoother, because they have less fiber content and a more sugary flavor. Lighter roasts have more caffeine, resulting in a slight bitterness, and a stronger flavor from aromatic oils and acids destroyed by longer roasting times. A small amount of chaff is produced during roasting from the skin left on the bean after processing. Chaff is usually removed from the beans by air movement, though a small amount is added to dark roast coffees to soak up oils on the beans. Decaffeination may also be part of the processing that coffee seeds undergo. Seeds are decaffeinated when they are still green. Many methods can remove caffeine from coffee, but all involve either soaking beans in hot water or steaming them, then using a solvent to dissolve caffeine-containing oils. Decaffeination is often done by processing companies, and the extracted caffeine is usually sold to the pharmaceutical industry.

## Storage
Once roasted, coffee beans must be stored properly to preserve the fresh taste of the bean.  Ideal conditions are air-tight and cool.  Air, moisture, heat and light are the environmental factors in order of importance to preserving flavor in coffee beans.
Typical commercial coffee containers in which coffee is purchased are generally not ideal for long-term storage. Some newer packages contain one-way valves which allow for the release of carbon dioxide (a byproduct of the roasting process) while preventing air from entering the bag.

## Preparation
Coffee beans must be ground and brewed in order to create a beverage. Grinding the roasted coffee beans is done at a roastery, in a grocery store, or in the home. They are most commonly ground at a roastery then packaged and sold to the consumer, though "whole bean" coffee can be ground at home. Coffee beans may be ground in several ways. A burr mill uses revolving elements to crush or tear the bean, an electric grinder chops the beans with blades moving at high speeds, and a mortar and pestle grinds the beans to a powder. The type of grind is often named after the brewing method for which it is generally used. Turkish grind is the finest grind, while coffee percolator or French press are the coarsest grind. The most common grinds are between the extremes; a medium grind is used in most common home coffee brewing machines.
Coffee may be brewed by several methods: boiled, steeped, or pressured. Brewing coffee by boiling was the earliest method, and Turkish coffee is an example of this method. It is prepared by powdering the beans with a mortar and pestle, then adding the powder to water and bringing it to a boil in a pot called a cezve or, in Greek, a briki. This produces a strong coffee with a layer of foam on the surface.
Machines such as percolators or automatic coffeemakers brew coffee by gravity. In an automatic coffeemaker, hot water  drips onto coffee grounds held in a coffee filter made of paper or perforated metal, allowing the water to seep through the ground coffee while absorbing its oils and essences. Gravity causes the liquid to pass into a carafe or pot while the used coffee grounds are retained in the filter. In a percolator, boiling water is forced into a chamber above a filter by pressure created by boiling. The water then passes downwards through the grounds due to gravity, repeating the process until shut off by an internal timer.
Coffee may also be brewed by steeping in a device such as a French press (also known as a cafetiere). Ground coffee and hot water are combined in a coffee press and left to brew for a few minutes. A plunger is then depressed to separate the coffee grounds, which remain at the bottom of the container. Because the coffee grounds are in direct contact with the water, all the coffee oils remain in the beverage, making it stronger and leaving more sediment than in coffee made by an automatic coffee machine.
The espresso method forces hot, but not boiling, pressurized water through ground coffee. As a result of brewing under high pressure (ideally between 9-10 atm) the espresso beverage is more concentrated (as much as 10 to 15 times the amount of coffee to water as gravity brewing methods can produce) and has a more complex physical and chemical constitution.  A well prepared espresso has a reddish-brown foam called crema that floats on the surface. The drink "Americano" is popularly thought to have been named after American soldiers in WW II who found the European way of drinking espresso too strong. Baristas would cut the espresso with hot water for them.

## Presentation
Once brewed, coffee may be presented in a variety of ways. Drip brewed, percolated, or French-pressed/cafetiere coffee may be served with no additives (colloquially known as black) or with either sugar, milk or cream, or both. When served cold, it is called iced coffee.
Espresso-based coffee has a wide variety of possible presentations.  In its most basic form, it is served alone as a "shot" or in the more watered down style cafe americanoa shot or two of espresso with hot water.  The Americano should be served with the espresso shots on top of the hot water to preserve the crema.  Milk can be added in various forms to espresso:  steamed milk makes a caffe latte, equal parts espresso and milk froth make a cappuccino, and a dollop of hot, foamed milk on top creates a caffe macchiato.
A number of products are sold for the convenience of consumers who do not want to prepare their own coffee. Instant coffee is dried into soluble powder or freeze dried into granules that can be quickly dissolved in hot water. Canned coffee has been popular in Asian countries for many years, particularly in Japan and South Korea. Vending machines typically sell varieties of flavored canned coffee, much like brewed or percolated coffee, available both hot and cold. Japanese convenience stores and groceries also have a wide availability of bottled coffee drinks, which are typically lightly sweetened and pre-blended with milk. Bottled coffee drinks are also consumed in the United States. Liquid coffee concentrates are sometimes used in large institutional situations where coffee needs to be produced for thousands of people at the same time. It is described as having a flavor about as good as low-grade robusta coffee and costs about 10 cents a cup to produce. The machines used can process up to 500 cups an hour, or 1,000 if the water is preheated.

# Social aspects
Coffee was initially used for spiritual reasons.  At least 1,000 years ago, traders brought coffee across the Red Sea into Arabia (modern day Yemen), where Muslim monks began cultivating the shrub in their gardens. At first, the Arabians made wine from the pulp of the fermented coffee berries. This beverage was known as qishr (kisher in modern usage) and was used during religious ceremonies.
Coffee became the substitute beverage in place of wine in spiritual practices where wine was forbidden. Coffee drinking was briefly prohibited to Muslims as haraam in the early years of the 16th century, but this was quickly overturned. Use in religious rites among the Sufi branch of Islam led to coffee's being put on trial in Mecca, accused of being a heretic substance, and its production and consumption was briefly repressed. It was later prohibited in Ottoman Turkey under an edict by the Sultan Murad IV. Coffee, regarded as a Muslim drink, was prohibited to Ethiopian Orthodox Christians until as late as 1889; it is now considered a national drink of Ethiopia for people of all faiths. Its early association in Europe with rebellious political activities led to its banning in England, among other places.
A contemporary example of coffee prohibition can be found in The Church of Jesus Christ of Latter-day Saints, a religion with over 13 million followers worldwide, which calls for coffee abstinence. The organization claims that it is both physically and spiritually unhealthy to consume coffee. This comes from the Mormon doctrine of health, given in 1833 by Mormon founder Joseph Smith, in a revelation called the Word of Wisdom. It does not identify coffee by name, but includes the statement that "hot drinks are not for the belly", which has been interpreted to forbid both coffee and tea.

# Health and pharmacology
Scientific studies have examined the relationship between coffee consumption and an array of medical conditions. Most studies are contradictory as to whether coffee has any specific health benefits, and results are similarly conflicting regarding negative effects of coffee consumption.
Coffee appears to reduce the risk of Alzheimer's disease, Parkinson's disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver, and gout. Some health effects are due to the caffeine content of coffee, as the benefits are only observed in those who drink caffeinated coffee, while others appear to be due to other components. For example, the antioxidants in coffee prevent free radicals from causing cell damage.
Coffee's negative health effects are mostly due to its caffeine content. Research suggests that drinking caffeinated coffee can cause a temporary increase in the stiffening of arterial walls. Excess coffee consumption may lead to a magnesium deficiency or hypomagnesaemia, and may be a risk factor for coronary heart disease. Some studies suggest that it may have a mixed effect on short-term memory, by improving it when the information to be recalled is related to the current train of thought, but making it more difficult to recall unrelated information. Nevertheless, the mainstream view of medical experts is that drinking three 8-ounce (236 ml) cups of coffee per day (considered average or moderate consumption) does not have significant health risks for adults.
An American scientist Yaser Dorri has recently suggested that coffee beans can restore the appetite after cooking and refresh olfactory receptors. He believes the intense odorants in coffee release the sensory receptors in the nose. This scientist sugguest that people can regain their appetite by smelling coffee beans. He has suggested this method to be also used for animals in research institutes. 

## Caffeine content
Depending on the type of coffee and method of preparation, the caffeine content of a single serving can vary greatly. On average, a single cup of coffee of about 207 milliliters (7 fluid ounces) or a single shot of espresso of about 30 mL (1oz) can be expected to contain the following amounts of caffeine:
- Drip coffee: 115175 mg
- Espresso: 30 mg
- Colombian Espresso: 40 mg
- Brewed/Pressed: 80135 mg
- Instant: 65100 mg
- Decaf, brewed: 34 mg
- Decaf, instant: 23 mg

# Economics
Coffee ingestion on average is about a third of that of tap water in North America and Europe. Worldwide, 6.7 million metric tons of coffee were produced annually in 19982000, and the forecast is a rise to 7 million metric tons annually by 2010.
Brazil remains the largest coffee exporting nation, but in recent years Vietnam has become a major producer of robusta beans. Colombia is the third exporter and the largest producer of washed arabica coffee. Robusta coffees, traded in London at much lower prices than New York's arabica, are preferred by large industrial clients, such as multinational roasters and instant coffee producers, because of the lower cost. Four single roaster companies buy more than 50 percent of all of the annual production: Kraft, Nestle, Procter & Gamble, and Sara Lee. The preference of the "Big Four" coffee companies for cheap robusta is believed by many to have been a major contributing factor to the crash in coffee prices, and the demand for high-quality arabica beans is only slowly recovering. 
Many experts believe the giant influx of cheap green coffee after the collapse of the International Coffee Agreement of 19751989 led to the prolonged price crisis from 1989 to 2004. In 1997 the price of coffee in New York broke US$3.00/lb, but by late 2001 it had fallen to US$0.43/lb. In 2007, wholesale coffee was about US$1/lb (e.g. 69 cents in London in March to 134 cents in New York in October), with robusta being about 70% of the price of arabica.  Retail prices varied from an average of $3 in Poland to $3.50 in the US to $17 in the UK.
The concept of fair trade labeling, which  guarantees coffee growers a negotiated pre-harvest price, began with the Max Havelaar Foundation's labelling program in the Netherlands. In 2004, 24,222 metric tons out of 7,050,000 produced worldwide were fair trade; in 2005, 33,991 metric tons out of 6,685,000 were fair trade, an increase from 0.34 percent to 0.51 percent. A number of studies have shown that fair trade coffee has a positive impact on the communities that grow it.
A study in 2002 found that fair trade strengthened producer organizations, improved returns to small producers, and positively affected their quality of life. A 2003 study concluded that fair trade has "greatly improved the well-being of small-scale coffee farmers and their families" by providing access to credit and external development funding and greater access to training, giving them the ability to improve the quality of their coffee. The families of fair trade producers were also more stable than those who were not involved in fair trade, and their children had better access to education. A 2005 study of Bolivian coffee producers concluded that Fairtrade certification has had a positive impact on local coffee prices, economically benefiting all coffee producers, Fairtrade certified or not.
The production and consumption of "Fair Trade Coffee" has grown in recent years as some local and national coffee chains have started to offer fair trade alternatives.