Process

The coffee roasting process follows coffee processing and precedes coffee brewing. It consists essentially of sorting, roasting, cooling, and packaging 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 240Ц275 ∞C (464Ц527 ∞F), and the beans are roasted for a period of time ranging from 3 to 30 minutes.[1] Initially, the process is endothermic (absorbing heat), but at around 175 ∞C (347 ∞F) it becomes exothermic (giving off heat).[2] For the roaster, this means that the beans are heating themselves and an adjustment of the roaster's heat source might be required. At the end of the roasting cycle, the roasted beans are dumped from the roasting chamber and cooled with forced air. Sometimes, in large commercial roasters, the beans are first quenched with a fine water mist. Torrefacto is a roasting process used in Spain and parts of Latin America involving the addition of sugar. Coffee can be brewed in several different ways, but these methods fall into four main groups depending on how the water is introduced to the coffee grounds: decoction (through boiling), infusion (through steeping), gravitational percolation (known as drip brewing), or pressurized percolation (as with espresso). Brewed coffee, if kept hot, will deteriorate rapidly in flavor, and reheating such coffee tends to give it a "mud

y" flavor, as some compounds that impart flavor to coffee are destroyed if this is done. 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 refrigerated bottled coffee drinks being commonly available at convenience stores and grocery stores in the United States. Canned coffee is particularly popular in Japan and South Korea. Electronic coffee makers boil the water and brew the infusion with little human assistance and sometimes according to a timer. Some such devices also grind the beans automatically before brewing. In thermodynamics, the word endothermic describes a process or reaction in which the system absorbs energy from its surroundings in the form of heat. It is a modern coinage from Greek roots. The prefix endo- derives from the Greek word "endon" (?) meaning "within," and the latter part of the word comes from the Greek word root "therm" (-) meaning "hot." The intended sense is that of a reaction that depends on taking in heat if it is to proceed. The opposite of an endothermic process is an exothermic process, one that releases, "gives out" energy in the form of heat. Thus in each term (endothermic & exothermic) the prefix refers to where heat goes as the reaction occurs. The term endothermic was coined by Marcellin Berthelot (25 October 1827 Ц 18 March 1907). The concept is frequently applied in physical sciences to, for example, chemical reactions, where thermal energy (heat) is converted to chemical bond energy.