Manually, in pans and boilers, coffee was roasted until the 19th century. People did not use open fire, they used charcoal, which gave a more stable heat. Coffee beans were poured into pans with a thick bottom and roasted until it’s dark, stirring constantly. Method of home-roasting coffee has not changed nowadays. Maybe only the utensils have become more technological.In the second half of the 19th century, the demand for coffee in Europe rose sharply. It has become much more convenient to sell already roasted grains. Production, with the help of engineers and technologists, was transferred to an industrial basis. The first coffee roasting machines already had a cylindrical shape, but were heated, as before, with coal.Patent for this complex coffee roaster machine was received by Jabez Burns in 1864. His roaster mixed and unloaded the grain without stopping. The invention of gas heat sources in the 20th century greatly simplified and reduced the process of roasting coffee. Roasting time wasn’t more than 18 minutes, the grain was no longer charred on the walls of the frying cylinders. In the thirties of the 20th century, internal blowing was used for the first time. Hot air was delivered at high speed inside the unit, evenly heated all the raw products. The quality of coffee has improved markedly. Some modern factories still apply this method.Types of coffee roasters by construction:Centrifugal roasters, the tangential roasters, drum roasters and hot air roasters.Drum roasters are the most common. The capacity of industrial roasters reaches several centners, small roasting companies acquire roasters for 20-50 kg. The cafe sets models manufactured for roasting 1–5 kg, sometimes 5–10 kg.Modern coffee bean roasters can be equipped with a viewing window and a sampler, control panel and cyclone. They can be manually controlled or can be automated. To automate the process, the device is equipped with a sensor that allows you to take basic indicators. However, coffee master continuously monitors the process. He uses a sampler to take samples. This means, the process is never left to chance.