Coffee

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

A cup of black coffee.

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

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 original 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.

It is possible to buy green (raw) coffee beans and roast them yourself at home in an oven or in some designs of air popcorn popper.

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 which fall into three main groups depending upon how the water is introduced to the coffee grounds.

Boiling:
- Turkish (or 'Greek' or 'Arab') coffee. The original 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) or cezve (Turkish), 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 builing water through the separated coffee grounds in the middle section, the resultant strong, 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

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 is an espresso with frothed milk and sometimes sugar and cocoa on top.
Latté is a single shot of espresso with steamed (not frothed) 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.
Indian filter coffee, particularly common in the south of the country, is made by adding milk to a coffee decoction prepared by the drip brew method.
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.

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", however it is so clearly distinguishable from normal coffee that most consider it a different drink (despite what some instant coffee adverts may say).

Social aspects of coffee

See Coffeehouse for the social history of coffee. For specifically Italian traditions, see Caffé.

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.

Coffee as a stimulant

Coffee contains caffeine, which acts as a stimulant. For this reason, it is mostly drunk 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" when their energy is fading. "Decaf" (coffee from which most of the caffeine has been removed by water or a chemical solvent such as 'tri') is available for people who wish to enjoy the taste of coffee without stimulation. 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.

Coffee as a fertilizer

Spent coffee grounds is a good fertilizer in gardens because of its high nitrogen content. Nitrogen is a crucial component of DNA, RNA and 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 make themselves 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 that ask.

Health risks

The caffeine in coffee is associated with addiction and various other health risks. Most coffee drinkers are familiar with "coffee jitters", a nervous condition that occurs when one has had too much caffeine. In recent years, research has indicated health benefits for drinking tea, inducing some coffee drinkers to switch to tea. Tea also contains caffeine, though in lesser amounts.

Some studies have assessed the health risks of coffee directly. For example, 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 were at 220% increased risk compared to non-drinkers.

References