Italian roasted coffee beans

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, taste, smell and density. Unroasted beans boast all of coffee’s acids, protein, and caffeine — but none of its taste. It takes heat to spark the chemical reactions that turn carbohydrates and fats into aromatic oils, burn off moisture and carbon dioxide, and alternately break down and build up acids, unlocking the characteristic coffee flavor. Image File history File links Download high resolution version (1704x2272, 859 KB) Espresso-roasted coffee beans. ... Image File history File links Download high resolution version (1704x2272, 859 KB) Espresso-roasted coffee beans. ... Traditional coffee drying in Boquete, Panamá Processing of coffee is the method converting the raw fruit of the coffee plant (cherry) into the commodity green coffee. ... For other uses, see Coffee (disambiguation). ...

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 maximise 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 roast level of the beans.

Process

The coffee roasting process consists essentially of cleaning, roasting, cooling, grinding, and packaging operations. 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 a few minutes to about 30 minutes. Roasters are typically horizontal rotating drums that tumble the green coffee beans in a current of hot combustion gases; however some other common types of roasters use electricity or even heat from wood. The roasters operate in either batch or continuous modes and can be indirect- or direct-fired. Look up hopper in Wiktionary, the free dictionary. ... For other uses, see Fahrenheit (disambiguation). ... For other uses, see Celsius (disambiguation). ... Roast is a term used in a number of contexts. ...

Many people who roast coffee prefer to follow a "recipe", or roast profile, when bringing out the flavour 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, water sprays are used to "quench" the beans. Following roasting, the beans are cooled and run through a "destoner". Destoners are air classifiers that remove stones, metal fragments, and other waste not removed during initial screening from the beans. The destoners pneumatically convey the beans to a hopper, where the beans are stabilized and dried. This stabilization process is called equilibration. Following equilibration, the roasted beans are either ground or packaged as whole beans. Roasted whole beans can be considered fresh for up to, but not exceeding one month. Once coffee is ground it is best used within 24 hours.

Packaging

Extending 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 de-gas 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. Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

Darkness

As the bean absorbs heat, the color shifts to yellow and then to a light "cinnamon" brown then to a dark brown. During 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 Mountain 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. Java coffee is a coffee produced on the island of Java. ... Kenya is the 17th largest producer of coffee in the world. ... Kona coffee is the market name for a variety of coffee (Coffea arabica) cultivated on the slopes of Mount Hualalai and Mauna Loa in the North and South Kona Districts of the Big Island of Hawaii. ... Jamaican Blue Mountain Coffee is a classification of coffee grown in the Blue Mountains of Jamaica. ...

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.

Grades of coffee roasting; from left: unroasted (or "green"), light, cinnamon, medium, high, city, full city, Italian, and French.

Image File history File links Coffee_roasting_grades. ... Image File history File links Coffee_roasting_grades. ...

Home roasting

Main article: Home roasting coffee

Home 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. Start of roast End of roast Chaff // Home roasting is the process of obtaining green coffee beans and roasting them on a small scale for personal consumption. ...

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 control

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Particulate matter (PM), volatile organic compounds (VOC), organic acids, and combustion products are the principal emissions from coffee processing. 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) and carbon 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. Image File history File links Question_book-3. ... Particulates, alternately referred to as Particulate Matter (PM) , aerosols or fine particles are tiny particles of solid or liquid suspended in the air. ... This article describes a highly specialized aspect of its subject in the Terminology and legal definitions section. ... An organic acid is an organic compound that is an acid. ... Many of the compounds which are dangerous to the environment can also be harmful to humans in the long-term range and come from mineral and fossil sources or are produced by humans themselves. ... This article does not cite any references or sources. ... An aldehyde. ... An organic acid is an organic compound that is an acid. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... This article is about the chemical element. ... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Decaffeination is the act of removing caffeine from coffee beans and tea. ... Instant coffee Instant coffee is a beverage derived from brewed coffee beans. ...

Particulate matter emissions from the receiving, storage, cleaning, roasting, cooling, andstoning 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. This article is about the meteorological phenomenon. ... It has been suggested that this article or section be merged into Catalysis. ... Spray drying is the process of mixing and drying a slurry (a kind of suspension) to form a homogeneous mixture of powders. ... Figure 1 - Venturi scrubber with mist eliminator Wet scrubbers are a form of pollution control technology. ...

Gallery

Unroasted coffee beans at various stages L–R: one year after drying, after drying, fresh picked. Gallery of unroasted coffee beans at various stages R-L: fresh picked, after drying, 1 year after drying. ...

Unroasted coffee beans at later stages. The beans are 7 and 8 years old. Gallery of unroasted coffee beans at later stages R-L: 7 years after harvest, 8 years after harvest. ...

An old large-capacity coffee roaster made from cast iron. Roasting coffee using an old cast-iron roaster fueled using wood. ...

Roasted coffee beans Download high resolution version (1600x1200, 585 KB) Wikipedia does not have an article with this exact name. ...

See also

• Coffee
• French press