A cup of coffee

Coffee as a drink, usually served hot, is prepared from the roasted seeds (beans) of the coffee plant.

Coffee bean types

There are two main species of the coffee plant; Arabica is the traditional coffee, and considered superior in flavor. Robusta, which is higher in caffeine, can be cultivated in environments where Arabica will not thrive, leading to its use as an inexpensive substitute for Arabica in many commercial coffee products. Robusta is not usually consumed by itself, due to its bitter and acidic flavor. Higher quality Robustas are used as ingredients in some espresso blends.

Arabica coffees were traditionally named by the port they were exported from, the two oldest being Mocha and Java. The modern coffee trade is much more specific about origin, labeling coffees by country, region, and sometimes even the producing estate. Coffee aficionados may even distinguish auctioned coffees by lot number.

One unusual and very expensive variety of robusta is the Indonesian Kopi Luwak. The beans are collected from the droppings of the Common Palm Civet, whose digestive processes give it a distinctive flavour.

Preparation

Aging

Although not well-known, certain types of coffee are known to improve with age; they obtain a less acidic, more well-balanced flavor. Several coffee producers sell coffee beans that have been aged to 3 years, and there are several specialty stores (such as Toko Aroma in Bandung, Indonesia) which age their unroasted beans to 8 years.

Roasting

The roasting process is integral to producing a savory cup of coffee. When roasted, the green coffee bean expands to nearly double its original size, changing in color and density. As the bean absorbs heat, the color shifts to yellow and then to a light "cinnamon" brown. During roasting oils appear on the surface of the bean. The roast will continue to darken until it is removed from the heat source.

At lighter roasts, the bean will exhibit more of its "origin flavor" - the flavors created in the bean by the soil and weather conditions in the location where it was grown. Coffee beans from famous regions like Java and Kenya are usually roasted lightly so their signature characteristics dominate the flavor.

As the beans darken to a deep brown, the origin flavors of the bean are eclipsed by the flavors created by the roasting process itself. At darker roasts, the "roast flavor" is so dominant that it can be difficult to distinguish the origin of the beans used in the roast. These roasts are sold by the degree of roast, ranging from "Light Cinnamon Roast" through "Vienna Roast" to "French Roast" and beyond.

In the 19th century coffee was usually bought in the form of green beans and roasted in a frying pan. This form of roasting requires much skill to do well, and fell out of favor when vacuum sealing of pre-roasted coffee became possible. Unfortunately, because coffee emits CO₂ for days after it is roasted, one must allow the coffee to get slightly stale before it can be vacuum sealed. For this reason two technologies have recently been employed: Illy has begun to use pressurized cans and many roasters bag whole beans immediately after roasting in bags with pressure release valves. Today home roasting is becoming popular again. Computerized drum roasters are available which simplify home roasting, and some home roasters will simply roast in an oven or in air popcorn poppers. Once roasted, coffee loses its flavor quickly. Although some prefer to wait 24 hours after roasting to brew the first cup, all agree that it begins to get off-flavors and bitterness about a week after roasting even under ideal conditions.

Grinding

The fineness of the grounds has a major impact on flavour, with finer grinding leading to a more intense and full flavour. The main reason to use coarser grounds is simply to prevent the grounds from being pushed through coarser filter types (such as the cafetière).

There are two methods of producing coffee grounds ready for brewing.

• Grinding: burr based with two revolving elements crushing or "tearing" the bean and with less risk of burning. Burr grinders can be either wheel or conical with the latter being quieter and having less chance of clogging.
  • Conical Burr Grinders preserve the most aroma and can grind very fine and very consistent. The intricate design of the steel burrs allow a high gear reduction to slow down the grinding speed. The slower the speed the less heat is imparted to the ground coffee thus preserving maximum amount of aroma. Because of the wide range of grind settings these grinders are ideal for all kinds of coffee equipment, Espresso, Drip, Percolators, French Press. The better Conical Burr Grinders can also grind extra fine for the preparation of Turkish coffee. Grinding speed is generally below 500 rpm.
  • Burr Grinders with disk type burrs grind at a faster speed than conical burr grinders and create a bit more warmth in the coffee (10,000 to 20,000 rpm). They are the most economical way of getting a consistent grind in a wide range of applications. They are well suited for most home pump espresso machines. However they do not grind as fine as Conical Burr Grinders.
• Chopping: Most modern 'grinders' actually chop the bean into pieces. Although giving a similar result to proper grinding, purists suggest that the result is less effective.
  • Blade Grinders “smash” the beans with a blade at very high speed (20,000 to 30,000 rpm). The ground coffee has larger and smaller particles and is warmer than ground coffee from burr grinders. Blade grinders create “coffee dust” which can clog up sieves in espresso machines and French presses. These type of grinders are suitable for drip coffee makers. They also can do a great job for grinding spices and herbs. They are not recommended for use with pump espresso machines.
• Pounding: Turkish coffee is produced from an infusion where the beans are pounded nearly to dust in a mortar and pestle. It produces grounds which are too fine for other preparation methods.

Brewing

Coffee can be brewed in several different ways, but these methods fall into four main groups depending upon how the water is introduced to the coffee grounds.

• Boiling:
  • Turkish coffee. A very early method of making coffee, still used in the Middle East, North Africa, Turkey and Greece, is to put the water together with very finely ground coffee in a narrow-topped pot called an ibrik (Arabic), cezve (Turkish), dzezva(Serbo-Croatian) still used videly in the western balkans, and allow it to briefly come to the boil. It is sometimes drunk sweet, in which case sugar is added to the pot and boiled with the coffee; it also often flavoured with cardamom. The result is small cups of very strong coffee with a foam on the top and thick layer of sludgy grounds at the bottom of the cup.

• Pressure:
  • Espresso is made with pressurised hot water and is the basis for many coffee drinks, or can be served alone (often after an evening meal). It is one of the strongest forms of coffee regularly drunk and has a distinctive flavour and crema.
  • A Percolator (or mocha pot) is a three-chamber design which boils water in the lower section and forces the boiling water through the separated coffee grounds in the middle section. The resultant, almost espresso strength, coffee (although without the crema) is collected in the upper section. It usually sits directly on a heater or stove.

• Gravity:
  • Drip brew (or filter coffee) is made by letting hot water drip onto coffee grounds held in a filter (paper or perforated metal). Strength varies according to the ratio of water to coffee, but is typically weaker than espresso.
  • A second type of Percolator also uses gravity to pass the water through the grounds but can produce a stronger result.

• Steeping:
  • A French press (or cafetière) is a tall narrow glass cylinder with a plunger that includes a filter. The coffee and hot water are mixed in the cylinder (normally for a few minutes) before the plunger, in the form of a metal foil, is depressed, leaving the coffee at the top ready to be poured.
  • Coffee bags (akin to tea bags) are much rarer than their tea equivalents, as they are much bulkier (more coffee is required in a coffee bag than tea in a tea bag).

Coffee in all these forms is made with coffee grounds (coffee beans that have been roasted and ground) and hot water, the grounds either remaining behind or being filtered out of the cup or jug after the main soluble compounds have been removed. The fineness of the grinding required differs by the method of intended drink production.

Electronic coffee makers boil the water and brew the infusion with little human assistance and sometimes according to a timer. Connoisseurs shun such conveniences, which compromise the flavor of the coffee; they prefer freshly ground beans and traditional brewing techniques.

Presentation

A cup of black coffee.

• Black coffee is drip brew, percolated or French press style coffee served without milk; sugar may be added.
• White coffee is coffee with milk added after preparation, perhaps with sugar.
• Cappuccino comprises equal parts espresso, steamed milk, and frothed milk in 4.5 oz. (served in a 5 oz. cup), is occasionally garnished with powdered cinnamon, other spices, or cocoa.
• Café Latte (plainly Latte, which is Italian for "milk," in America) is espresso with steamed milk, traditionally topped with frothed milk. It is not as strong as a Cappuccino because of a greater quantity of milk.
• A Café au lait is like a Latte except that drip-brewed coffee is used instead of espresso, with an equal amount of milk. Sugar is added to taste.
• Americano style coffee is made with espresso (normally several shots) and hot water to give a similar strength (but different flavour) from drip brewed coffee.
• Iced coffee is normally served with milk and sugar.
• Flavoured coffee: In some cultures, flavored coffees are common. Chocolate is a common additive that is either sprinkled on top or added to the coffee to imitate the taste of Mocha. Other flavourings include spices such as cinnamon, nutmeg, cardamom or Italian syrups.
• Irish coffee is hot brewed coffee spiked with whiskey and with a layer of cream on the top.

Frothy Madras filter coffee

• Indian (Madras) filter coffee, particularly common in the south of the country, is prepared off rough ground dark roasted coffee beans (Arabica, PeaBerry). The coffee is drip brewed for a few hours in a traditional metal Coffee filter before being served with milk and sugar. The ratio is usually (1/4 - decoction, 3/4 - milk).
• Vietnamese style coffee is another form of drip brew. In this form, hot water is allowed to drip though a metal mesh into a cup with the resulting strong brew being poured over ice into a glass containing sweetened condensed milk. Due to the high volume of coffee grounds required to make strong coffee in this fashion the brewing process is quite slow.
• Greek coffee or Turkish coffee is made by boiling finely ground coffee and water together in an ibrik, whic is a long-handled, open, brass or copper pot. When done, it is poured directly into tiny demitasse cups, along with the fine grounds. The coffee is then allowed to settle before consumption. Spice and sugar are often added into the mix.
• Kopi tubruk is an Indonesian-style coffee similar in presentation to the Greek coffee. However, kopi tubruk is made from coarse coffee grounds, and is boiled together with a solid lump of sugar. It is popular on the islands of Java and Bali and their surroundings.
• Coffee Pots come in many shapes and sizes. Traditional coloring uses brown or black colored pots for regular caffeinated coffee, and orange is used for decaffeinated coffee.

Instant coffee

Instant and soluble coffee has been freeze dried into soluble powder or granules. It is distinct from fresh coffee and is prepared differently. Opinions on instant coffee range from "intolerable imposter" to "reasonable alternative" to "better than the real thing". In countries where it is popular it is often referred to as "Café Puro" to the horror of coffee aficionados.

Social aspects of coffee

See also: Coffeehouse for a social history of coffee, and caffé for specifically Italian traditions.

The United States is the largest market for coffee, followed by Germany. Finland consumes the most coffee per capita. Coffee is so popular in Canada, the United States, and Europe that many restaurants specialize in coffee; these are called "coffeehouses" or "cafés". Most cafés also serve tea, sandwiches, pastries, and other light refreshments. Some cafés are miniature shacks that specialize in coffee to go for hurried travelers. Some travelers transport their coffee in vacuum bottles, which can keep a beverage hot for hours.

In some countries, notably in northern Europe, coffee parties are a popular form of entertaining. Besides coffee, the host or hostess at the coffee party also serves cake and pastries, hopefully homemade.

The stimulant properties of coffee and the fact that coffee does not adversely impact higher mental functions causes coffee to be associated with white collar jobs. Social habits involving coffee include the morning coffee and coffee breaks.

See also dunk (biscuit) for the habit of dipping one's biscuit or cake into one's coffee.

Coffee as a stimulant

Coffee contains caffeine, which acts as a stimulant. For this reason, it is often consumed in the morning and during working hours. Students preparing for examinations with late-night "cram sessions" use coffee to maintain their concentration. Office workers take a "coffee break" whenever their energy is diminished. Decaffeinated coffee, or "decaf", is coffee from which most of the caffeine has been removed by water or a chemical solvent such as trichloroethylene ("tri"). There are also tisanes that resemble coffee in taste but contain no caffeine (see below).

Coffee dependence is widespread and withdrawal symptoms are real. See the caffeine article for more on the pharmacological effects of caffeine.

Recent research has uncovered additional stimulating effects of coffee which are not related to the caffeine. Coffee contains an as yet unknown chemical agent which stimulates the production of cortisone and adrenaline, two stimulating hormones.

Coffee as a fertilizer

Spent coffee grounds are a good fertilizer in gardens because of their high nitrogen content. Nitrogen is a crucial component of DNA, RNA and of the proteins which plants require to build themselves. Coffee grounds also contain potassium, phosphorus and many other trace elements that aid plant development. Many gardeners report that roses love coffee grounds and when furnished with the same become big and colorful.

Coffee grounds can be obtained inexpensively (usually free) from local coffee shops. Large coffee shop chains may have a policy of composting coffee grounds or giving them away to those who ask.

Health

Benefits

Coffee increases the effectiveness of pain killers -- especially migraine medications -- and can rid some people of asthma. Some of the beneficial effects may be restricted to one sex, for instance it has been shown to reduce suicide for women, and prevent gallstones and gallbladder disease in men. It also reduces the incidence of diabetes in both sexes, but reduces the risk by about 30% in women and over 50% in men. There are of course the reasons most people drink coffee such as its ability to increase short term recall and increase IQ. It also changes the metabolism of a person so that their body burns a higher proportion of lipids to carbohydrates, which can help athletes avoid muscle fatigue. Coffee can also reduce the incidence of liver cirrhosis and prevent colon and bladder cancers. Finally, coffee reduces the incidence of heart disease, though whether this is simply because it rids your blood of excess fat or because of its stimulant effect is unknown.

Some of these health effects are realized by as little as 4 cups a day (24 oz), but others kick in at 6 or more cups a day (32 oz or more).

NOTE: Health benefits of decaffeinated coffee have not been found.

Risks

Many coffee drinkers are familiar with "coffee jitters", a nervous condition that occurs when one has had too much caffeine. Coffee can also increase blood pressure among those with high blood pressure, but follow-up studies showed that coffee still decreased the chance of dying from heart disease in the aggregate. Coffee can also cause insomnia in some, while paradoxically it helps a few sleep more soundly. It can also cause anxiety and irritability, in some with excessive coffee consumption, and some as a withdrawal symptom. There are also sex specific effects, in some PMS sufferers it increases the symptoms, and it can reduce fertility in women, also it may increase the risk of osteoporosis in postmenopausal women, and there may be risks to a fetus if a pregnant woman drinks 8 or more cups a day (48 oz or more).

A February 2003 Danish study of 18,478 women linked heavy coffee consumption during pregnancy to significantly increased risk of stillbirths (but no significantly increased risk of infant death in the first year). "The results seem to indicate a threshold effect around four to seven cups per day," the study reported. Those who drank eight or more cups a day (48 oz or more) were at 220% increased risk compared to non-drinkers. This study has not yet been repeated but has caused some doctors to caution against excessive coffee consumption during pregnancy.

A study published in 2004 in the American Journal of Clinical Nutrition (abstract available online at [1] (http://www.ajcn.org/cgi/content/abstract/80/4/862)) tried to discover why the beneficial and detrimental effects of coffee are conflicting and found that consumption of coffee is associated with significant elevations in biochemical markers of inflammation. This is a detrimental effect of coffee on the cardiovascular system which may explain why coffee has so far only been shown to help the heart at levels of 4 or less cups a day (20oz or less).

Caffeine is toxic in high enough doses. It is unlikely though, that a toxic dose will be ingested in form of common drinks. In concentrated forms such as pills or powders it can be taken in sufficient quantities to cause vomiting, unconsciousness, and even death. A single box of caffeine pills can be fatal if taken at one time.

NOTE: The health risks of decaffeinated coffee have not been studied.

References

• CoffeeFaq.com: Information about the various major methods of coffee preparation (http://coffeefaq.com/coffaq9.htm)
• about.com: Blade vs Burr grinders (http://coffeetea.about.com/library/weekly/aa021603bladeburr.htm)
• TooMuchCoffee: The European Coffee and Espresso Resource (http://www.toomuchcoffee.com/) Offers non-commercial articles and discussion about coffee, coffee preparations and homeroasting.
• Coffeekid.com (http://www.coffeekid.com): Information about coffee making, and essays on various aspects of coffee presentation.