Coffee preparation

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Coffee preparation is the process of turning coffee beans into a beverage. While the particular steps needed vary with the type of coffee desired and with the raw material being utilized, the process is composed of four basic steps; raw coffee beans must be roasted, the roasted coffee beans must then be ground, the ground coffee must then be mixed with hot water for a certain time (brewed), and finally the liquid coffee must be separated from the now used and unwanted grounds.

Coffee is always brewed by the user immediately before drinking. In most areas, coffee may be purchased unprocessed, or already roasted, or already roasted and ground. Coffee is often vacuum packed to prevent oxidation and lengthen its shelf life.


[edit] Roasting

Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products.

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 then to a dark and oily color. During roasting, oils appear on the surface of the bean. The roast will continue to darken until it is removed from the heat source.

Coffee can be roasted with ordinary kitchen equipment (frying pan, grill, oven, popcorn popper) or by specialised appliances.

[edit] Grinding

An old-fashioned manual coffee grinder.

The whole coffee beans are ground, also known as milling, to facilitate the brewing process.

The fineness of grind strongly affects brewing, and must be matched to the brewing method for best results. Brewing methods which expose coffee grounds to heated water for longer 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 weak coffee unless more is used. Due to the importance of fineness, uniformly ground coffee is better than a mixture of sizes.

Ground coffee deteriorates faster than roasted beans because of the greater surface area exposed to oxygen. Many coffee drinkers grind the beans themselves immediately before brewing.

There are four methods of grinding coffee for brewing: burr-grinding, chopping, pounding, and roller grinding.

[edit] Burr-grinding

A burr grinder.

Burr mills use two revolving abrasive elements, such as wheels or conical grinding elements, between which the coffee beans are crushed or "torn" with little frictional heating. Both manually and electrically powered mills are available. These mills grind the coffee to a fairly uniform size determined by the separation of the two abrasive surfaces between which the coffee is ground; the uniform grind produces a more even extraction when brewed, without excessively fine particles that clog filters.

These mills offer a wide range of grind settings, making them suitable to grind coffee for various brewing systems such as espresso, drip, percolators, French press, and others. Better conical burr grinders can also grind very fine for the preparation of Turkish coffee.

  • Conical burr grinders use steel burrs which allow them to grind effectively while rotating relatively slowly, usually below 500 rpm, reducing frictional heating of the ground coffee, thus preserving maximum aroma. Conical burr grinders are quieter and less likely to clog than disk grinders.
  • Grinders with disk-type burrs usually rotate faster than conical burr grinders, and consequently warm the ground coffee a little by friction, manual models less than electrical. They are cheaper than conical burr grinders, and are well suited for home coffee preparation.

[edit] Chopping

A coffeegrinder

Coffee beans can be chopped by using blades rotating at high speed (20,000 to 30,000 RPM), either in a device designed specifically for coffee, or in a general use home blender. Devices of this sort are cheaper and longer-lasting than true grinders, but the grind is not homogeneous and will produce particles of widely varying sizes where ideally all particles should have the same size, right for the method of brewing. The ground coffee is also warmed by friction.

Blade grinders create “coffee dust” that can clog up sieves in espresso machines and French presses, and are best suited for drip coffee makers, though even here the drink is not as good[citation needed]. They are not recommended for grinding coffee for use with pump espresso machines.

[edit] Pounding

Turkish coffee requires that the grounds be almost powdery in fineness. While this can be attained by some electric burr grinders, pounding the beans with a mortar and pestle can pulverize the coffee to the required size. For industrial scale production, turkish coffee is ground either with a stone grinder or a roller grinder.

[edit] Roller Grinding

In a roller grinder, the beans are ground between pairs of corrugated rollers. A roller grinder produces a more even grind size distribution and heats the ground coffee less than other grinding methods. However, due to their size and cost, roller grinders are used exclusively by commercial and industrial scale coffee producers.

Water-cooled roller grinders are used for high production rates as well as for fine grinds such as Turkish and espresso.

[edit] 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). If the water is repeatedly cycled through the beans (as with the common percolator), the brew will also contain more of the relatively less soluble, and bitter-tasting, compounds found in the bean, but less ground coffee will be required.

Water temperature is crucial to the proper extraction of flavor from the ground coffee. The recommended brewing temperature of coffee is 200 °F (93 °C). If cooler, some of the solubles that make up the flavor will not be extracted. If the water is too hot, some undesirable, bitter, elements will be extracted, adversely affecting the taste. If coffee is heated to boiling point only very briefly, the taste will be little affected; the longer it is kept at a high temperature the worse the taste becomes.

The usual ratio of coffee to water for the style of coffee most prevalent in Europe, America, and other Westernized nations (evident in publications such as textbooks on coffee and instruction manuals for drip-brew machines) is between one and two tablespoons of ground coffee per six ounces (180 millilitres) of water; the full two tablespoons per six ounces tends to be recommended by experienced coffee lovers. The fineness of grind and method of brewing affect the strength.

Brewed coffee kept hot 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, and sealed containers of brewed coffee are sometimes commercially available in food stores in America or Europe, with Frappuccino being commonly available at convenience stores and grocery stores in the United States.

Electronic coffee makers boil the water and brew the infusion with little human assistance and sometimes according to a timer. Some grind beans automatically before brewing.

[edit] Boiling

Despite the name, care should be taken not to actually boil coffee for more than an instant because it becomes bitter.

  • The simplest method is to put the ground coffee in a cup, pour in hot water and let it cool while the grounds sink to the bottom. This is a traditional method for making a cup of coffee that is still used in parts of Indonesia. This method (known as "mud coffee" in the Middle East owing to an extremely fine grind that results in a mud-like sludge at the bottom of the cup) allows for extremely simple preparation, but the drinker must be careful if they want to avoid drinking grounds either from this layer or floating at the surface of the coffee (which can be avoided by dribbling cold water onto the 'floaters' from the back of a spoon). If the coffee beans are not ground finely enough, the grounds do not sink.
  • "Cowboy coffee" is made by simply heating coarse grounds with water in a pot, letting the grounds settle and pouring off the liquid to drink, sometimes filtering it to remove fine grounds. While the name suggests that this method was derived from or used by cowboys, presumably on the trail around a campfire, it is also seen among others who do not drink coffee frequently and/or lack any specialized equipment for brewing. Some coffee aficionados actually prefer this method. In Finland, Norway and Sweden, which have the highest consumption of coffee per-capita[1], this is the traditional way to make coffee.

The above methods are sometimes used with hot milk instead of water.

  • Turkish coffee aka Greek coffee was a very early method of making coffee and is still used in the Middle East, North Africa, East Africa, Turkey, Greece, Balkans and Russia. Very finely ground coffee, optionally sugar, and water are placed in a narrow-topped pot, called an ibrik (Arabic), cezve (Turkish), kanaka (Egyptian), briki (Greek), džezva (Štokavian) or turka (Russian) and brought to the boil then immediately removed from the heat. It may be very briefly brought to the boil two or three times. Turkish coffee is often flavored with cardamom, particularly in Arab countries. The resulting strong coffee, with foam on the top and a thick layer of sludgy grounds at the bottom, "telve" in Turkish, and often referred to in English as the "mud", is drunk from small cups.

[edit] Steeping

  • A cafetière (or French press) is a tall, narrow cylinder with a plunger that includes a metal or nylon mesh filter. Coffee is placed in the cylinder and boiling water is poured in. The coffee and hot water are left in the cylinder for a few minutes (typically 4'-7') and the plunger is pushed down leaving the filter immediately above the grounds, allowing the coffee to be poured out while the filter retains the grounds. Depending on the type of filter, it is important to pay attention to the grind of the coffee beans, though a rather coarse grind is almost always called for.[1]. A plain glass cylinder may be used, or a vacuum flask arrangement to keep the coffee hot (not to be confused with a vacuum brewer; see below).
  • Coffee bags are less often used than tea bags. They are simply disposable bags containing coffee; the grounds do not mix with the water so no extra filtering is required.
  • 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, primarily of the varieties Robusta and Liberica which are often strong-flavored, allowing the ground coffee in the sock to be reused.
  • 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 apparatus 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.
  • The AeroPress is a device invented in 2005 that combines steeping and pressure. Hot water is poured onto ground coffee, similarly to a French press, but soon after the coffee is forced through a paper microfilter using pressure. This filter allows a finer grind and removes more of the sediment than the stainless steel mesh filter of a French press.

[edit] 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, though the final product contains more caffeine. By convention, regular coffee brewed by this method is served in a brown or black pot (or a pot with a brown or black handle), while decaffeinated coffee is served in an orange pot (or a pot with an orange handle).
  • A variation is the traditional Neapolitan flip coffee pot, or Napoletana, a drip brew coffee maker for the stovetop. It consists of a bottom section filled with water, a middle filter section, and an upside-down pot placed on the top. When the water boils, the coffee maker is flipped over to let the water filter through the coffee grounds.
  • The common electric percolator — which was in almost universal use in the United States prior to the 1970s, and is still popular in some households today — differs from the pressure percolator described above. 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 some coffee aficionados because of this multiple-pass process. Many coffee drinkers still prefer gravity percolation because they claim it delivers a richer cup of coffee in comparison to drip brewing.
  • Another variation is cold-brewed coffee, sometimes known as "cold press." Cold water is poured over coffee grounds and allowed to steep for eight to twenty-four hours. The coffee is then filtered, usually through a very thick filter, removing all particles. This process produces a very strong concentrate which can be stored in a refrigerated, airtight container for up to eight weeks. The coffee can then be prepared for drinking by adding hot water to the concentrate at an approximately 3:1 ratio (water to concentrate), but can be adjusted to the drinker's preference. The coffee prepared by this method is very low-acid with a smooth taste, and is often preferred by those with sensitive stomachs. Others, however, feel this method strips coffee of its bold flavour and character. This method is not common and there are few appliances designed for it.

It may be interesting to note that the amount of coffee used affects both the strength and the flavour of the brew in a typical filter coffee maker. The softer flavours come out of the coffee first and the more bitter flavours only after some time, so a large brew will tend to be both stronger and more bitter. This can be modified by stopping the filtration after a planned time and then adding hot water to the brew instead of waiting for all the water to pass through the grounds.

[edit] Pressure

  • Espresso is made with hot water at between 91 °C (195 °F) and 96 °C (204 °F) forced, under a pressure of between eight and nine atmospheres (800–900 kPa), through a lightly packed matrix (called a puck) 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 flavor and crema, a layer of emulsified oils in the form of a colloidal foam standing over the liquid.
A variation on the a moka pot (the upper section formed as a coffee fountain).
  • A moka pot, also known as "Italian coffeepot" is a three-chamber design which boils water in the lower section and forces the boiling water through coffee grounds held in the middle section, separated by a filter mesh from the top section. The resultant coffee (almost espresso strength, but without the crema) is collected in the upper section. These pots usually sit directly on a heater or stove. Some models have a transparent glass or plastic top.
  • Various types of single-serving coffee machines force hot water under pressure through a coffee pod composed of finely ground coffee sandwiched between two layers of filter paper or a proprietary capsule containing ground coffee. Examples include the pod-based Senseo and Home Café systems and the proprietary Tassimo and K-Cup systems.

[edit] Separation

Coffee in all these forms is made with roasted and ground coffee and hot water, the used grounds either remaining behind or being filtered out of the cup or jug after the main soluble compounds have been extracted. The fineness of grind required differs for the various brewing methods.

[edit] Gallery of common brewing methods


Gravity and steeping:

[edit] Coffee storage

Coffee loses aroma and flavour with storage, as the volatile components evaporate.[citation needed] Coffee beans are generally considered fresh up to 14 days after roasting. It is suggested to grind right before brewing to get the best result since aroma components are lost by up to 50% after 5 minutes of being ground. Roasted coffee can be stored for some time, depending on factors such as roast degree, UV light, humidity, etc.[citation needed]Vacuum-packing is not proven to extend storage life significantly. It is always better to buy small amounts of coffee for use over a short period of time, for example one week.[citation needed] No matter what methods are used to preserve roasted or ground coffee, aromas will still escape through time, and there is no method that can store coffee permanently without degradation of flavour. Some may suggest freezing roasted coffee beans to extend the shelf life, however, care must be taken of that no water droplets condense on the coffee. Otherwise much of the aroma will be lost. One suggested approach to freezing coffee beans is to double-wrap the package and allow it to defrost for at least 30 minutes before opening the package. This can decrease the chance that any water condenses on coffee beans. It is important to understand that no methods can preserve coffee aroma completely, or extend its shelf life miraculously. The best method is to buy small amounts of coffee every time and consume it as soon as possible. Some people suggests that ageing coffee beans for 3 days will allow aroma to develop to its full extent. This is not always true since every type of coffee bean is different. Also, the ageing time of coffee beans differs when the roast degree is different. Generally, the darker the roast, the short the ageing time, if any, is needed.

[edit] Instant coffee

Instant coffee is made commercially by drying prepared coffee; the resulting soluble powder is dissolved in hot water by the user, and sugar/sweeteners and milk added as desired.

  • Instant Coffee without water

Another way to enjoy instant coffee is "without water". Boil milk, add coffee and sugar to taste.

[edit] Presentation

[edit] Hot drinks


[edit] Espresso-based, without milk

  • Espresso: see above under heading Pressure.
  • Americano style coffee is made with espresso (normally several shots), topped with hot water to give a similar strength (but different flavor) to drip-brewed coffee; famous in America.[citation needed]
  • Bica is a Portuguese espresso, but a little bit softer.
  • Long black is similar to Americano, but prepared in different order (a double shot of espresso is added to water instead of vice versa); famous in Australia.
  • Lungo is different from an Americano. It is usually a double shot of espresso run through the machine; all the water runs through the beans, as opposed to adding water.
  • Ristretto is an espresso made with less than the usual amount of water, filling a small espresso cup half-full of very strong coffee.

[edit] Espresso-based, with milk

  • Caffè breve is an American variation of a latte: a milk-based espresso drink using steamed half-and-half (light - 10 per cent - cream) instead of milk.
  • Caffè latte or caffè e latte is often called simply latte, which is Italian for "milk", in English-speaking countries; it is espresso with steamed milk, traditionally topped with froth created from steaming the milk. A latte comprises one-third espresso and nearly two-thirds steamed milk. More frothed milk makes it weaker than a cappuccino. A latte is also commonly served in a tall glass; if the espresso is slowly poured into the frothed milk from the rim of the glass, three layers of different shades will form, with the milk at the bottom, the froth on top and the espresso in between. A latte may be sweetened with sugar or flavored syrup. Caramel and vanilla and other flavors are used.
A café Latte.
  • Caffè macchiato, sometimes Espresso macchiato or "short" macchiato — macchiato meaning "spotted" — is an espresso with a little steamed milk added to the top, usually 30-60 ml (1–2 oz), sometimes sweetened with sugar or flavored syrup. This differs from latte macchiato below which is milk "spotted" with espresso.
  • Cappuccino comprises equal parts of espresso coffee and milk and froth, sometimes sprinkled with cinnamon or powdered cocoa.
  • Flat white is one part espresso with two parts steamed milk, but no foam, usually served in a cappuccino cup. This is a specialty of Australia and New Zealand, particularly favored in the latter. The difference between a flat white and a latte is that a flat white is usually stronger, served in a smaller cup, and has no foam.
  • Galão is a Bica (Portuguese espresso) to which is added hot milk, tapped from a canister and sprayed into the glass in which it is served.
  • Latte macchiato is the inverse of a caffè macchiato, being a tall glass of steamed milk spotted with a small amount of espresso, sometimes sweetened with sugar or syrup.
  • Mocha is a latte with chocolate added.

[edit] Brewed or boiled, non espresso-based

Cream being poured into drip coffee.
  • Black coffee is drip-brewed, percolated, vacuum brewed, or French-press-style coffee served without cream. Some add sugar.
  • White coffee is black coffee with unheated milk added. Some add sugar. (Note: though having a similar term, this is not to be confused with the Beirut herbal tea from Lebanon or the Malaysian Ipoh white coffee).
  • Café au lait is similar to latte except that drip-brewed coffee is used instead of espresso, with an equal amount of milk. Some add sugar.
  • Kopi tubruk is an Indonesian-style coffee similar in presentation to Turkish 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.
  • Indian (Madras) filter coffee, particularly common in southern India, is prepared with rough-ground dark roasted coffee beans (e.g., Arabica, PeaBerry), and chicory. 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.
  • Greek coffee is prepared similarly to Turkish coffee. The main difference is that the coffee beans are ground into a finer powder and sugar is added during the process. It does not contain other flavours and usually is usually never served with milk. Greek coffee is served in a small cup with a handle, and accompanied always by a small cookie and a glass of water. A similar method to the Greek preparation is used in Colombia to make 'tinta', strong black coffee that is often brewed with panela, a sugar concentrate in cake form. A muslin or fine-cloth bag is used to strain the grounds.
  • 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.

[edit] Fortified coffee

  • Red Eye is one espresso shot added to a cup of coffee (typically 210-480 ml, 7-16 oz). Some add milk or sugar.
  • Black Eye is two espresso shots added to a cup of coffee (typically 210-480 ml, 7-16oz). Some add milk or sugar.

[edit] Flavored coffees

Madras filter coffee, still in its dabarah and tumbler.
  • Flavored coffee: In some cultures, flavored coffees are common. Chocolate is a common additive that is either sprinkled on top or mixed with the coffee to imitate the taste of Mocha. Other flavorings include spices such as cinnamon, nutmeg, cardamom, or Italian syrups. In the Maghreb, the orange blossom is used as a flavoring. Vanilla- and hazelnut-flavored coffees are common in the United States; these are usually artificially flavored.
  • Turkish coffee 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 is usually made sweet, with sugar added after the brew process begins, and often is flavored with cardamom or other spices. In many places it is customary to serve it with a tall glass of water on the side.
  • Chicory is sometimes combined with coffee as a flavoring agent, as in the style of coffee served at the famous Café du Monde in New Orleans. Chicory has historically been used as a coffee substitute when real coffee was scarce, as in wartime. Chicory is popular as an additive in Belgium and is an ingredient in Madras filter coffee.

[edit] Alcoholic coffee drinks

Alcoholic spirits and liqueurs can be added to coffee, often sweetened and with cream floated on top. These beverages are often given names according to the alcoholic addition:

  • Black coffee with brandy, or marc, or grappa, or other strong spirit.
  • Irish coffee, with Irish whiskey, sugar, and cream. There are many variants, essentially the same but with the use of a different spirit:
    • Café au Drambuie, with Drambuie instead of whiskey
    • Caribbean or Jamaican coffee, with dark rum
    • Gaelic or Scotch coffee, with Scotch whisky
    • Kahlua coffee, with Kahlua liqueur
    • and a great many others.

[edit] Cold drinks

  • Iced coffee is a cold version of hot coffee, typically drip or espresso diluted with ice water. Iced coffee can also be an iced or chilled form of any drink in this list.
  • 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 Turkish coffee, especially in the spring and summer months. Frappé is served cold, with a drinking straw, either with or without sugar or milk.
  • Ice-blended coffee (trade names: Frappuccino, Ice Storm) is a variation of iced coffee. The term Frappucino was coined by Starbucks (a portmanteau of Frappé and Cappuccino: Frappuccino). Other coffeehouses serve similar concoctions, but under different names, since "Frappuccino" is a Starbucks trademark. One commonly used by many stores is Ice Storm. Another prominent example is the Javakula at Seattle's Best Coffee. A frappuccino is an iced latte, mocha, or macchiato mixed with crushed ice and flavorings (such as vanilla/hazelnut if requested by the customer) and blended.
  • 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.
  • Igloo Espresso a regular espresso shot poured over a small amount of crushed ice, served in an espresso cup. Sometimes it is requested to be sweetened as the pouring over the ice causes the shot to become bitter. Originating in Italy and has migrated to Australian coffee shops.
  • Cold brewed coffee Toddy coffee is a filtered, drip-style process of brewing coffee slowly (12 hours) with cold water to produce a strong coffee concentrate, often served diluted with water or milk of choice.

[edit] Confectionery (Non-drinks)

  • Chocolate-covered roasted coffee beans are available as a confection; eating them delivers more caffeine to the body than does drinking the same mass (or volume) of brewed coffee (ratios depend upon the brewing method) and has similar physiological effects, unless the beans have been decaffeinated.

[edit] References

[edit] External links

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