The Coffee History
The history of the coffee
In the 15th century in the Ottoman Empire and Greater Persia they started to roast coffee beans using perforated pans made from metal or porcelain. The pan was equipped with a long handle so that it could be held over a container of hot coals until the coffee was roasted. The beans were stirred with a spoon. The first cylinder roaster with a crank to keep the beans in motion appeared in Cairo around 1650. It was made of metal and was held over a brazier or open fire. French, Dutch and Italian variations of this design quickly appeared. These became very popular over the next century in Europe, England and the American colonies.
In the 19th century patents were made to roast large amounts of coffee, but home roasting continued to be popular, as everyone roasted coffee in the kitchen oven. In 1849 a spherical coffee roaster was invented in Cincinnati, Ohio, for use on the top of a wood-fired kitchen stove, fitted into a burner opening. Green beans were available at the local general store, or even through mail order. For roasting, many people used such simple methods as a layer of beans on a metal sheet in the oven, or beans stirred in a cast iron skillet over a fire.
The commercial roaster inventions patented by Burns revolutionized the U.S. roasting industry, much like the innovations of inventors in Emmerich am Rhein greatly advanced commercial coffee roasting in Germany. As well, in 1864 the marketing breakthrough of the Arbuckle Brothers in Philadelphia, introducing the convenient one-pound (0.45 kg) paper bag of roasted coffee, brought success and imitators. From that time commercially roasted coffee grew in popularity until it gradually overtook home roasting during the 1900s in America. In 1903 and 1906 the first electric roasters were patented in the U.S. and Germany. These commercial devices eliminated the problem of smoke or fuel vapor imparting a bad taste to the coffee. In France, the home roaster did not yield to the commercial roaster until after the 1920s. Coffee was roasted to a dark color in small batches at home and by shopkeepers, using a variety of appliances including ones with a rotating cylinder of glass, sheet iron or wire mesh, and ones driven by hand, clockwork or electric motor. Because of the smoke and blowing chaff, country dwellers generally roasted outdoors.
A hand-cranked wood stove top coffee roaster ca 1890–1910
In the 1950s just as instant coffee was becoming a popular coffee drink, speciality coffee-houses began to offer a more traditionally brewed beverage. In the 1970s, more speciality coffee houses opened, ones that offered a variety of roasts and beans from around the world. In the 1980s and 1990s, the gourmet coffee industry experienced great growth. Through the 1970s and 1980s, the Siemens Sirocco home roaster was made in West Germany and marketed globally. It was a small fluidbed roaster made for the home enthusiast. The product was named after a commercial hot-air roasting process which itself was named after the hot Sahara winds called sirocco. In 1976, chemical engineer Michael Sivetz patented a competing hot air design for manufacture in the U.S.; this became popular as an economical alternative. Sivetz called for the home roaster to focus on the quality of the bean. From 1986 through 1999 there was a surge in the number of patents filed for home roasting appliances. In the 1990s, more electric home roasting equipment became available, including drum roasters, and variations on the fluidbed roaster. By 2001, gourmet coffee aficionados were using the internet to purchase green estate-grown beans for delivery by mail.
The Coffee Process
The coffee-roasting 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 machineopened, 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. Initially, the process is endothermic (absorbing heat), but at around 175 °C (347 °F) it becomes exothermic (giving off heat). 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 air cooled with a draft inducer.
During the roasting process, coffee beans tend to go through a weight loss of about 15 to 18% due to the loss of water and volatile compounds. Although the beans experience a weight loss, the size of the beans double after the roasting process because of the physical expansion of the cellulose structure which facilitates the release of carbon dioxide, volatile organic compounds, and water in the form of steam.
There are several traditional variations in bean roasting in different parts of the world
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