Coffee

Coffee as a drink, usually served hot, is prepared from the roasted seeds (beans) of the coffee plant. Due to its popularity, coffee is, in monetary terms, the second largest traded commodity in the world (after oil). It is one of mankind's chief sources of the stimulant caffeine. Because of this, coffee's nutritional benefits are disputed, sometimes labeled a cure-all, other times labeled a health hazard (see caffeinism).

Preparation

Aging

Although it is still widely debated, certain types of green coffee are believed to improve with age; especially those that are valued for their low-acidity, such as coffees from Indonesia or India. Several of these coffee producers sell coffee beans that have been aged for as long as 3 years, with some as long as 8 years.

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However, most coffee experts agree that a green coffee peaks in flavor and freshness within one year of harvest.

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Roasting

:See also: Coffee Roasting

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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 this stage the moisture in the beans is expelled. Coffee beans will crack during the roasting process, not unlike popping popcorn. "First crack" and "second crack" are benchmarks that a roaster will use to gauge how the roast progresses. The beans will continue to darken and the oils will begin to be expelled to the surface until the beans are removed from the heat source.

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Image:Cofffeebeans_aging_a.jpg|Unroasted coffee beans at various stages R-L: fresh picked, after drying, 1 year after drying. Photos taken at Toko Aroma in Bandung, Indonesia.

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Image:coffeebeans_aging_b.jpg|Unroasted coffee beans at later stages. The beans are 7 and 8 years old. Photos taken at Toko Aroma in Bandung, Indonesia.

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Image:coffeeroasting_woodfired.jpg|An old large-capacity coffee roaster made from cast-iron. It is wood-fired, and is located at Toko Aroma, Bandung, Indonesia

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Image:Roasted_coffee_beans.jpg|Roasted coffee beans

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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. A roasting method native to the Ipoh town in Malaysia involves the inclusion of butter and sugar during the roasting process, producing a variety of roast known as the Ipoh "white" coffee.

Related Topics:
Kenya - Ipoh - Butter - Ipoh "white" coffee

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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 "Vienna Roast" to "French Roast" and beyond. The dividing line between extremely dark roast and "burnt" is a matter of some debate. Contrary to popular belief, the darker roasts and more strongly flavored coffees do not deliver any more caffeine than lighter roasts. In the United States, major national coffee suppliers tailor their product to tastes in particular regions of the country; for instance, a can of ground coffee purchased in the Northeast or Northwest will contain a darker roast than an identically appearing can purchased in the central United States.

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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. 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 makers.

Related Topics:
19th century - Home roasters - Oven - Popcorn

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Because coffee emits CO2 for days after it is roasted, one must allow the coffee to degas before it can be packaged in sealed containers. For this reason many roasters who package whole beans immediately after roasting in bags with one-way valves, allowing the CO2 to escape but nothing in. This CO2 also affects the flavor of the brewed coffee, and most experts recommend a 2-5 day "resting" period post-roast for the CO2 to sufficiently escape.

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Once roasted, the volatile compounds that give coffee its complex flavors dissipate quickly. Despite the varying claims of "what is fresh" when it comes to coffee, the industry-leaders in specialty coffee generally agree that roasted coffee should be ground and brewed no more than about 14 days off-the-roast. Some companies have tried to extend the freshness, using a nitrogen infusion system that flushes the inert gas into the roasted coffee, replacing the oxygen, ostensibly reducing oxidation. However, as is said in the coffee industry, "the proof is in the cup."

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Grinding

The fineness of the grounds has a major impact on the brewing process, and matching the consistency of the grind with the brewing method is critical to extracting the optimal amount of flavour from the roasted beans. Brewing methods which expose coffee grounds to heated water for a longer duration of time require a coarser grind than faster brewing methods. Beans which are too finely ground for the brewing method in which they are used will expose too much surface area to the heated water and produce a bitter, harsh, "over-extracted" taste. At the other extreme, an overly coarse grind will produce a weak, watery, under-flavoured result.

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The rate of deterioration increases when the coffee is ground, as a result of the greater surface area exposed to oxygen. Until relatively recently, it was almost impossible to find whole beans in American stores, with ground coffee being the only variety available. With the rise of coffee as a gourmet beverage, it has become much more popular to grind the beans at home before brewing, and there are many home appliances available which are dedicated to the process.

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

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• 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. Burr grinders "mill" the coffee to a reasonably consistent size, which produces a more even extraction when brewed. Coffee experts consider burr grinders to be the only acceptable way to grind coffee.
• Conical Burr Grinders preserve the most aroma and can grind very fine and very consistently. 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 usually grind at a faster speed than conical burr grinders and as a result tend to create a bit more warmth in the coffee. They are the most economical way of getting a consistent grind in a wide range of applications. They are well suited for most home coffee preparation.
• Chopping: Most modern "grinders" actually chop the bean into pieces (and some coffee drinkers merely use a home blender to do the job). Although enjoying a much longer life before wearing out the blades, the results are dramatically less effective in producing a homogenously ground result and, as a result, will create inconsistent extraction and a degraded product in the cup.
• 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 (in theory) only suitable for drip coffee makers though even here the product is inferior as a result. 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 by infusion with grounds of almost powdery fineness. In the absence of a sufficiently high-quality burr grinder, the only reliable way to achieve this is to pound the beans in a mortar and pestle.

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. If the method allows the water to pass only once through the grounds, the resulting brew will contain mainly the more soluble components (including caffeine), whereas if the water is repeatedly cycled through the beans (as with the common percolator), the brew will contain more of the relatively less soluble compounds found in the bean; as these tend to be more bitter; that type of process is less favored by coffee aficionados.

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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 grind required differs by the method of extraction.

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Water temperature is crucial to the proper extraction of flavor from the ground coffee. The recommended brewing temperature of coffee is 93 ºC (204 ºF). Any cooler, and some of the solubles that make up the flavor will not be extracted. If the water is too hot, some undesirable elements will be extracted, adversely affecting the taste, especially in bitterness.

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• Boiling: Despite the name, care should be taken not to actually boil the coffee (or at least not for too long) because that will make it bitter.
• The simplest method is to put the ground coffee in a cup, pour hot water in it and let it stand to let it cool and let the ground sink to the bottom. One should not drink this to the end unless one wants to 'eat' the ground coffee (which some people don't mind). The advantage of this method are that it is simple and that the water temperature is just right.
• Turkish coffee was a very early method of making coffee and is still used in the Middle East, North Africa, Turkey, and Greece. Water is placed together with very finely ground coffee in a narrow-topped pot, called an ibrik (Arabic), cezve (Turkish), briki (Greek), or dzezva (Serbo-Croatian), and allow it to briefly come to the boil. It is usually drunk sweet, in which case sugar is added to the pot and boiled with the coffee; it is also often flavoured with cardamom. The result is imbibed in small cups of very strong coffee with a foam on the top and thick layer of sludgy grounds at the bottom of the cup, often referred to as the "mud".
• "Cowboy coffee" is made by simply boiling coarse grounds with water in a pot, letting the grounds settle and pouring off the liquid to drink. While the name suggests that this method was derived or used by cowboys, presumably on the trail around a campfire, it is also frequently seen among others who do not drink coffee frequently and lack any specialized equipment for otherwise brewing.
• Pressure:
• Espresso is made with hot water at between 91 °C (195 °F) and 96 °C (204 °F) forced, under between eight and nine atmospheres (800-900 kPa) of pressure, through a tightly packed matrix of finely ground coffee. It can be served alone (often after an evening meal), and is the basis for many coffee drinks. It is one of the strongest tasting forms of coffee regularly consumed, with a distinctive flavour and crema, the emulsified oils in the form of a colloidal foam standing over the liquid.
• A percolator (or mocha/moka 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 coffee (almost espresso strength, yet without the crema) is collected in the upper section. It usually sits directly on a heater or stove. Some models feature a glass or plastic top to view the coffee as it is forced up.
• A vacuum brewer consists of two chambers: a pot below, atop which is set a bowl or funnel with its siphon descending nearly to the bottom of the pot. The bottom of the bowl is blocked by a filter of glass, cloth or plastic, and the bowl and pot are joined by a gasket that forms a tight seal. Water is placed in the pot, the coffee grounds are placed in the bowl, and the whole affair is set over a burner. As the water heats, it is forced by the increasing vapor pressure up the siphon and into the bowl where it mixes with the grounds. When all the water possible has been forced into the bowl the brewer is removed from the heat. As the water vapor in the pot cools it contracts, forming a partial vacuum and drawing the coffee down through the filter.
• Gravity:
• Drip brew (also known as filter or American coffee) is made by letting hot water drip onto coffee grounds held in a coffee filter (paper or perforated metal). Strength varies according to the ratio of water to coffee and the fineness of the grind, but is typically weaker than espresso.
• The common electric percolator which was almost universal prior to the 1970s and is still popular today differs from the pressure percolator described above, in that it uses the pressure of the boiling water to force it to a chamber above the grounds, but relies on gravity to pass the water down through the grounds, where it then repeats the process until shut off by an internal timer. The coffee produced is held in low esteem by coffee aficionados because of this multiple pass process.
• Steeping:
• A cafetière (or French press) is a tall narrow glass cylinder with a plunger that includes a filter. The coffee and hot water are combined in the cylinder (normally for four minutes) before the plunger, in the form of a metal foil, is depressed, leaving the coffee at the top ready to be poured. This style of "total immersion brewing" is considered by many coffee experts to be the ideal way to prepare fine coffee at home.
• 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).
• Malaysian coffee is often brewed using a "sock", which is really just a muslin bag shaped like a filter into which coffee is loaded then steeped into hot water. This method is especially suitable for use with local-brew coffees in Malaysia, which are often much stronger in flavour, allowing the ground coffee in the sock to be re-used.

Electronic coffee makers boil the water and brew the infusion with little human assistance and sometimes according to a timer. Some even grind the beans automatically before brewing. Connoisseurs shun such conveniences as compromising the flavor of the coffee; they prefer freshly ground beans and traditional brewing techniques.

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Presentation

• Black coffee is drip-brew, percolated, vacuum brewed, 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 fl oz (130 mL) (served in a 5 fl oz (150 mL) cup), is occasionally garnished with powdered cinnamon, other spices, or cocoa.
• Latte (as it is known in the USA, Italian for "milk" - originally caffè e latte or café latte) is espresso with steamed milk, traditionally topped with frothed milk. A latte comprises one-third espresso and nearly two-thirds steamed milk. Less frothed milk makes it more mild than a cappuccino (weaker), and a traditional latte is served an average 10-20 degrees celsius cooler than a black or white coffee or a cappuccino.
• Café au lait is similar to 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. The sugar should be added to the coffee while it is hot, before icing it, as sugar won't dissolve well in cold coffee.
• Flavoured coffee: In some cultures, flavoured 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. In the Maghreb, the orange blossom is used as a flavoring.
• Irish coffee is hot brewed coffee spiked with whiskey and with a layer of cream on the top.
• Indian (Madras) filter coffee, particularly common in southern India, is prepared off rough ground dark roasted coffee beans (e.g., 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, and the resulting strong brew is poured into a glass containing sweetened condensed milk which may contain ice. Due to the high volume of coffee grounds required to make strong coffee in this fashion, the brewing process is quite slow. It is also highly popular in Cambodia and Laos.
• Turkish coffee, also called Greek coffee or Armenian coffee (Surj), is served in very small cups about the size of those used for espresso. Traditional Turkish coffee cups have no handles, but modern ones often do. The crema or "face" is considered crucial, and since it requires some skill to achieve its presence is taken as evidence of a well-made brew. (See above for preparation method.) It's usually made sweet, with sugar added before the brew process begins, and often is flavored with cardamom or other spices. In many places it's customary to serve it with a tall glass of water on the side.
• Kopi tubruk is an Indonesian-style coffee similar in presentation to 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.
• A demitasse is somewhat similar to an espresso without the crema: a small cup of strong black coffee often served after a meal.
• Coffee pots come in many shapes and sizes. Traditional coloring uses brown or black colored pots for regular caffeinated coffee, and orange for decaffeinated coffee.
• Brewed coffee continually heated will deteriorate rapidly in flavor; even at room temperature, deterioration will occur. However, if kept in an oxygen-free environment, it can last almost indefinitely at room temperature; sealed containers of brewed coffee are sometimes commercially available in food stores in America or Europe.
• Thai iced coffee is a popular drink commonly offered at Thai restaurants in the United States. It consists of coffee, ice, and sweetened condensed milk.
• Chocolate-covered roasted coffee beans are available as a confection; unless the beans have been decaffeinated, these will deliver the same caffeine content as brewed coffee and have the same physiological effects.
• Frappé is a cold coffee drink made from instant coffee. It was created in Greece in 1957 in the city of Thessaloniki. This type of coffee is probably consumed in Greece more than traditional Greek coffee, especially in the spring and summer months. Frappé is served cold, with a drinking straw, either with or without sugar or milk.