Date: 7th December 2009
Source: wikipedia.org
Comment: Discover how your coffee is roasted and the journey your coffee takes from green beans through to roasted beans.
Dark roasted coffee beansLight roasted coffee beansRoasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell, and density. Unroasted beans contain similar acids, protein, and caffeine as those that have been roasted, but lack the taste. It takes heat to speed up the Maillard and other chemical reactions that develop and enhance the flavor.
As green coffee is more stable than roasted, the roasting process tends to take place close to where it will be consumed. This reduces the time that roasted coffee spends in distribution, helping to maximize its shelf life. The vast majority of coffee is roasted commercially on a large scale, but some coffee drinkers roast coffee themselves in order to have more control over the freshness and flavor profile of the beans.
ProcessThe coffee roasting process consists essentially of sorting, roasting, cooling, and packaging operations but can also include grinding in larger scale roasting houses. In larger operations, bags of green coffee beans are hand or machine-opened, dumped into a hopper, and screened to remove debris. The green beans are then weighed and transferred by belt or pneumatic conveyor to storage hoppers. From the storage hoppers, the green beans are conveyed to the roaster. Roasters typically operate at temperatures between 370 and 540 °F (188 and 282 °C), and the beans are roasted for a period of time ranging from 3 to 30 minutes. Roasters are typically horizontal rotating drums that are heated from below and tumble the green coffee beans in a current of hot gases. The heat source can be supplied by natural gas, liquefied petroleum gas (LPG), electricity or even wood. These roasters can operate in either batch or continuous modes and can be indirect- or direct-fired.
An alternate to the drum coffee roaster was developed by Michael Sivetz for which he was given US patent 3,964,175 on June 22, 1976. It involves roasting the coffee beans while they are levitated on a cushion of heated air. The process is called a fluidized bedand is commonly used in other food processing applications.
Many people who roast coffee prefer to follow a "recipe", or roast profile, when bringing out the flavor characteristics they wish to highlight. Any number of factors may help a person determine the best profile to use, such as the coffee's origin, varietal, processing method or desired flavour characteristics. A roast profile can be presented as a graph showing time on one axis and temperature on the other, which can be recorded manually or using computer software and data loggers linked to temperature probes inside various parts of the roaster.
Indirect-fired roasters are roasters in which the burner flame does not contact the coffee beans, although the combustion gases from the burner do contact the beans. Direct-fired roasters contact the beans with the burner flame and the combustion gases. At the end of the roasting cycle, the roasted beans are cooled using a vacuum system. Roasted coffee beans are also cooled using fine water mist, which is known as "quenching" and is considered inferior to air cooling as the water soaks the fresh beans with moisture and oxygen particles making it stale almost instantly. Following roasting, the beans are cooled and stabilized. This stabilization process is called degassing. Following degassing, the roasted beans are packaged, usually in light-resistant foil bags fitted with small one-way valves to allow gasses to escape while protecting the beans from moisture and oxygen. Roasted whole beans can be considered fresh for up to one month. Once coffee is ground it is best used immediately.
To watch a fully automated electric coffee roaster in action please click[1].
PackagingExtending the useful life of roasted coffee relies on maintaining an optimum environment for the beans. The first large scale preservation technique was vacuum packing. However, because coffee emits CO2 after roasting, coffee to be vacuum packed must be allowed to degas for several days before it is sealed. To allow more immediate packaging, pressurized canisters or foil-lined bags with pressure-relief valves can be used.
DarknessAs the bean absorbs heat, the color shifts to yellow and then to varying shades of brown. During the later stages of roasting, oils appear on the surface of the bean, making it shiny. 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, Kenya, Hawaiian Kona, and Jamaican Blue Mountainare usually roasted lightly so their signature characteristics dominate the flavor.[1] 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.
A note on flavor: Describing the tastes of different roasts is as subjective as putting a wine into words. In both cases there’s no substitute for your own personal taste. As a guide, if you can see the oil on the beans as in the image above, you are more likely to taste the roasting flavours than the individual characteristics of the beans.
Roast levelNotesSurfaceFlavorLightCinnamon roast, half city, New EnglandAfter several minutes the beans “pop” or "crack" and visibly expand in size. This stage is called first crack. American mass-market roasters typically stop here.DryLighter-bodied, higher acidity, no obvious roast flavourMediumFull city, American, regular, breakfast, brownAfter a few short minutes the beans reach this roast, which U.S. specialty sellers tend to prefer.DrySweeter than light roast; more body exhibiting more balance in acid, aroma, and complexity.Full RoastHigh, Viennese, Italian Espresso, ContinentalAfter a few more minutes the beans begin popping again, and oils rise to the surface. This is called second crack.Slightly shinySomewhat spicy; complexity is traded for heavier body/mouth-feel. Aromas and flavours of roast become clearly evident.Double RoastFrenchAfter a few more minutes or so the beans begin to smoke. The bean sugars begin to carbonize.Very oilySmokey-sweet; light bodied, but quite intense. None of the inherent flavors of the bean are recognisable.Grades of coffee roasting; from left: unroasted (or "green"), light, cinnamon, medium, high, city, full city, Italian, and French.
Home roastingHome roasting is the process of roasting small batches of green coffee beans for personal consumption. Roasting coffee in the home is something that has been practiced for centuries, and has included methods such as heating over fire coals, roasting in cast iron pans, and rotating iron drums over a fire or coal bed. Computerized drum roasters are available which simplify home roasting and some home roasters simply roast in an oven or in air popcorn poppers.
Up until the 20th century, it was more common for at-home coffee drinkers to roast their coffee in their residence than it was to buy roasted coffee. During the 20th century, home roasting faded in popularity with the rise of the commercial coffee roasting companies. In recent years home roasting of coffee has seen a revival. In some cases there is an economic advantage, but primarily it is a means to achieve finer control over the quality and characteristics of the finished product.
Emissions and controlParticulate matter (PM), volatile organic compounds (VOC), organic acids, and combustion products are the principal emissions from coffee processing[2]. Several operations are sources of PM emissions, including the cleaning and destoning equipment, roaster, cooler, and instant coffee drying equipment. The roaster is the main source of gaseous pollutants, including alcohols, aldehydes,organic acids, and nitrogen and sulfur compounds. Because roasters are typically natural gas-fired, carbon monoxide (CO) andcarbon dioxide (CO2) emissions result from fuel combustion. Decaffeination and instant coffee extraction and drying operations may also be sources of small amounts of VOC. Emissions from the grinding and packaging operations typically are not vented to the atmosphere.
Particulate matter emissions from the roasting and cooling operations are typically ducted to cyclones before being emitted to the atmosphere. Gaseous emissions from roasting operations are typically ducted to a thermal oxidiser or thermal catalytic oxidiser following PM removal by a cyclone. Some facilities use the burners that heat the roaster as thermal oxidisers. However, separate thermal oxidisers are more efficient because the desired operating temperature is typically between 650°C and 816°C (1200°F and 1500°F), which is 93°C to 260°C (200°F to 500°F) more than the maximum temperature of most roasters. Some facilities use thermal catalytic oxidizers, which require lower operating temperatures to achieve control efficiencies that are equivalent to standard thermal oxidisers. Catalysts are also used to improve the control efficiency of systems in which the roaster exhaust is ducted to the burners that heat the roaster. Emissions from spray dryers are typically controlled by a cyclone followed by a wet scrubber.
GalleryUnroasted coffee beans at various stages L–R: one year after drying, after drying, fresh picked.
Unroasted coffee beans at later stages. The beans are 7 and 8 years old.
An old large-capacity coffee roaster made from cast iron.
An example of lighter roasted, versus darker roasted beans. The degree of roasting which is ideal for coffee in general, and a given varietal or blend is highly subjective.
Production by country
Colombia · Costa Rica · Ecuador · El Salvador · Ethiopia · Guatemala · Haiti · India · Indonesia · Jamaica · Kenya · Papua New Guinea · The Philippines · USA · Vietnam
Coffee topics
History of coffee · Economics of coffee · Coffee and health · Coffee and the environment
Species and varieties
List of varieties · Coffea arabica: Kenya AA, Kona, Jamaican Blue Mountain · Coffea canephora (Coffea robusta): Kopi Luwak · Coffea liberica: Kape Barako · Single-origin
Major chemicals in coffee
Caffeine · Cafestol · Caffeic acid
Coffee processing
Coffee roasting · Home roasting coffee · Corretto · Decaffeination
Coffee preparation
Coffeemaker · Coffee percolator · Espresso (lungo, ristretto) · Espresso machine · Drip brew · French press · Turkish coffee · Vacuum coffee maker · Instant coffee · Chemex · Moka pot · AeroPress · Presso · Knockbox
Popular coffee beverages
Affogato · Bicerin · Americano · Long black · Café au lait/Café con leche · Caffè corretto/Liqueur coffee · Cafe mocha · Cà phê sữa đá · Cappuccino · Coffee milk · Cortado · Espresso · Ipoh white coffee · Ristretto · Flat white · Frappuccino · Greek frappé coffee · Iced coffee · Indian filter coffee · Irish coffee · Latte · Macchiato (espresso, latte) · Red eye
Coffee substitutes
Barley tea · Barleycup · Caro · Chicory · Dandelion coffee · Pero · Postum · Roasted grain beverage
Coffee and lifestyle
Coffee culture · Coffee ceremony · Coffeehouse · List of coffeehouse chains · Coffee Palace · Barista · Caffè · Café · Kopi tiam · Viennese café · Caffè sospeso · Coffee cupping · Coffee break/Fika
Ethiopia is a major coffee grower and the region is known for its arabica coffee. Additionally, coffee has been in use in Ethiopia before its introduction to other regions. Please consider to add information pertaining to this mentioned points since it is historically and commercially relevant.
Source: wikipedia.org
Comment: Discover how your coffee is roasted and the journey your coffee takes from green beans through to roasted beans.
Dark roasted coffee beansLight roasted coffee beansRoasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell, and density. Unroasted beans contain similar acids, protein, and caffeine as those that have been roasted, but lack the taste. It takes heat to speed up the Maillard and other chemical reactions that develop and enhance the flavor.
As green coffee is more stable than roasted, the roasting process tends to take place close to where it will be consumed. This reduces the time that roasted coffee spends in distribution, helping to maximize its shelf life. The vast majority of coffee is roasted commercially on a large scale, but some coffee drinkers roast coffee themselves in order to have more control over the freshness and flavor profile of the beans.
ProcessThe coffee roasting process consists essentially of sorting, roasting, cooling, and packaging operations but can also include grinding in larger scale roasting houses. In larger operations, bags of green coffee beans are hand or machine-opened, dumped into a hopper, and screened to remove debris. The green beans are then weighed and transferred by belt or pneumatic conveyor to storage hoppers. From the storage hoppers, the green beans are conveyed to the roaster. Roasters typically operate at temperatures between 370 and 540 °F (188 and 282 °C), and the beans are roasted for a period of time ranging from 3 to 30 minutes. Roasters are typically horizontal rotating drums that are heated from below and tumble the green coffee beans in a current of hot gases. The heat source can be supplied by natural gas, liquefied petroleum gas (LPG), electricity or even wood. These roasters can operate in either batch or continuous modes and can be indirect- or direct-fired.
An alternate to the drum coffee roaster was developed by Michael Sivetz for which he was given US patent 3,964,175 on June 22, 1976. It involves roasting the coffee beans while they are levitated on a cushion of heated air. The process is called a fluidized bedand is commonly used in other food processing applications.
Many people who roast coffee prefer to follow a "recipe", or roast profile, when bringing out the flavor characteristics they wish to highlight. Any number of factors may help a person determine the best profile to use, such as the coffee's origin, varietal, processing method or desired flavour characteristics. A roast profile can be presented as a graph showing time on one axis and temperature on the other, which can be recorded manually or using computer software and data loggers linked to temperature probes inside various parts of the roaster.
Indirect-fired roasters are roasters in which the burner flame does not contact the coffee beans, although the combustion gases from the burner do contact the beans. Direct-fired roasters contact the beans with the burner flame and the combustion gases. At the end of the roasting cycle, the roasted beans are cooled using a vacuum system. Roasted coffee beans are also cooled using fine water mist, which is known as "quenching" and is considered inferior to air cooling as the water soaks the fresh beans with moisture and oxygen particles making it stale almost instantly. Following roasting, the beans are cooled and stabilized. This stabilization process is called degassing. Following degassing, the roasted beans are packaged, usually in light-resistant foil bags fitted with small one-way valves to allow gasses to escape while protecting the beans from moisture and oxygen. Roasted whole beans can be considered fresh for up to one month. Once coffee is ground it is best used immediately.
To watch a fully automated electric coffee roaster in action please click[1].
PackagingExtending the useful life of roasted coffee relies on maintaining an optimum environment for the beans. The first large scale preservation technique was vacuum packing. However, because coffee emits CO2 after roasting, coffee to be vacuum packed must be allowed to degas for several days before it is sealed. To allow more immediate packaging, pressurized canisters or foil-lined bags with pressure-relief valves can be used.
DarknessAs the bean absorbs heat, the color shifts to yellow and then to varying shades of brown. During the later stages of roasting, oils appear on the surface of the bean, making it shiny. 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, Kenya, Hawaiian Kona, and Jamaican Blue Mountainare usually roasted lightly so their signature characteristics dominate the flavor.[1] 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.
A note on flavor: Describing the tastes of different roasts is as subjective as putting a wine into words. In both cases there’s no substitute for your own personal taste. As a guide, if you can see the oil on the beans as in the image above, you are more likely to taste the roasting flavours than the individual characteristics of the beans.
Roast levelNotesSurfaceFlavorLightCinnamon roast, half city, New EnglandAfter several minutes the beans “pop” or "crack" and visibly expand in size. This stage is called first crack. American mass-market roasters typically stop here.DryLighter-bodied, higher acidity, no obvious roast flavourMediumFull city, American, regular, breakfast, brownAfter a few short minutes the beans reach this roast, which U.S. specialty sellers tend to prefer.DrySweeter than light roast; more body exhibiting more balance in acid, aroma, and complexity.Full RoastHigh, Viennese, Italian Espresso, ContinentalAfter a few more minutes the beans begin popping again, and oils rise to the surface. This is called second crack.Slightly shinySomewhat spicy; complexity is traded for heavier body/mouth-feel. Aromas and flavours of roast become clearly evident.Double RoastFrenchAfter a few more minutes or so the beans begin to smoke. The bean sugars begin to carbonize.Very oilySmokey-sweet; light bodied, but quite intense. None of the inherent flavors of the bean are recognisable.Grades of coffee roasting; from left: unroasted (or "green"), light, cinnamon, medium, high, city, full city, Italian, and French.
Home roastingHome roasting is the process of roasting small batches of green coffee beans for personal consumption. Roasting coffee in the home is something that has been practiced for centuries, and has included methods such as heating over fire coals, roasting in cast iron pans, and rotating iron drums over a fire or coal bed. Computerized drum roasters are available which simplify home roasting and some home roasters simply roast in an oven or in air popcorn poppers.
Up until the 20th century, it was more common for at-home coffee drinkers to roast their coffee in their residence than it was to buy roasted coffee. During the 20th century, home roasting faded in popularity with the rise of the commercial coffee roasting companies. In recent years home roasting of coffee has seen a revival. In some cases there is an economic advantage, but primarily it is a means to achieve finer control over the quality and characteristics of the finished product.
Emissions and controlParticulate matter (PM), volatile organic compounds (VOC), organic acids, and combustion products are the principal emissions from coffee processing[2]. Several operations are sources of PM emissions, including the cleaning and destoning equipment, roaster, cooler, and instant coffee drying equipment. The roaster is the main source of gaseous pollutants, including alcohols, aldehydes,organic acids, and nitrogen and sulfur compounds. Because roasters are typically natural gas-fired, carbon monoxide (CO) andcarbon dioxide (CO2) emissions result from fuel combustion. Decaffeination and instant coffee extraction and drying operations may also be sources of small amounts of VOC. Emissions from the grinding and packaging operations typically are not vented to the atmosphere.
Particulate matter emissions from the roasting and cooling operations are typically ducted to cyclones before being emitted to the atmosphere. Gaseous emissions from roasting operations are typically ducted to a thermal oxidiser or thermal catalytic oxidiser following PM removal by a cyclone. Some facilities use the burners that heat the roaster as thermal oxidisers. However, separate thermal oxidisers are more efficient because the desired operating temperature is typically between 650°C and 816°C (1200°F and 1500°F), which is 93°C to 260°C (200°F to 500°F) more than the maximum temperature of most roasters. Some facilities use thermal catalytic oxidizers, which require lower operating temperatures to achieve control efficiencies that are equivalent to standard thermal oxidisers. Catalysts are also used to improve the control efficiency of systems in which the roaster exhaust is ducted to the burners that heat the roaster. Emissions from spray dryers are typically controlled by a cyclone followed by a wet scrubber.
GalleryUnroasted coffee beans at various stages L–R: one year after drying, after drying, fresh picked.
Unroasted coffee beans at later stages. The beans are 7 and 8 years old.
An old large-capacity coffee roaster made from cast iron.
An example of lighter roasted, versus darker roasted beans. The degree of roasting which is ideal for coffee in general, and a given varietal or blend is highly subjective.
Production by country
Colombia · Costa Rica · Ecuador · El Salvador · Ethiopia · Guatemala · Haiti · India · Indonesia · Jamaica · Kenya · Papua New Guinea · The Philippines · USA · Vietnam
Coffee topics
History of coffee · Economics of coffee · Coffee and health · Coffee and the environment
Species and varieties
List of varieties · Coffea arabica: Kenya AA, Kona, Jamaican Blue Mountain · Coffea canephora (Coffea robusta): Kopi Luwak · Coffea liberica: Kape Barako · Single-origin
Major chemicals in coffee
Caffeine · Cafestol · Caffeic acid
Coffee processing
Coffee roasting · Home roasting coffee · Corretto · Decaffeination
Coffee preparation
Coffeemaker · Coffee percolator · Espresso (lungo, ristretto) · Espresso machine · Drip brew · French press · Turkish coffee · Vacuum coffee maker · Instant coffee · Chemex · Moka pot · AeroPress · Presso · Knockbox
Popular coffee beverages
Affogato · Bicerin · Americano · Long black · Café au lait/Café con leche · Caffè corretto/Liqueur coffee · Cafe mocha · Cà phê sữa đá · Cappuccino · Coffee milk · Cortado · Espresso · Ipoh white coffee · Ristretto · Flat white · Frappuccino · Greek frappé coffee · Iced coffee · Indian filter coffee · Irish coffee · Latte · Macchiato (espresso, latte) · Red eye
Coffee substitutes
Barley tea · Barleycup · Caro · Chicory · Dandelion coffee · Pero · Postum · Roasted grain beverage
Coffee and lifestyle
Coffee culture · Coffee ceremony · Coffeehouse · List of coffeehouse chains · Coffee Palace · Barista · Caffè · Café · Kopi tiam · Viennese café · Caffè sospeso · Coffee cupping · Coffee break/Fika
Ethiopia is a major coffee grower and the region is known for its arabica coffee. Additionally, coffee has been in use in Ethiopia before its introduction to other regions. Please consider to add information pertaining to this mentioned points since it is historically and commercially relevant.
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