Coffee roaster

Coffee preparation is the process of turning coffee beans into a beverage. While the particular steps vary with the type of coffee and with the raw materials, the process includes 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 used grounds. Coffee is usually brewed 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. Roasting coffee transforms the chemical and physical properties of green coffee beans. When roasted, the green coffee bean expands to nearly double its original size, changing in color and density. As the bean absorbs heat, its color shifts to yellow, then to a light 'cinnamon' brown, and then to a rich dark brown 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. A coffee roaster is a special pan or apparatus suitable to heat up and roast green coffee beans. The whole coffee beans are ground, also known as milling, to facilitate the brewing process.