Coffee roasting is one of the most important stages that determines the quality and taste of coffee. At the end of the nineteenth century and the beginning of the twentieth century, along with the development of the second industrial revolution, there were inventions about machines in many fields, including the field of coffee roasting. A lot of coffee roasters were born during this period, allowing to eliminate smoke or risks in manual roasting such as uneven ripening, burning, etc., and create many mutations in coffee flavor.
As one of the first roasting machines in the form of spherical drums of Probat Emmericher (Germany), with high pillars, sturdy iron frame, black spherical roasting cage attached by iron bars. The drum-shaped roaster has a opening lid, and around the body are iron buttons, manufactured in the most advanced fashion of that period. This is the same type of roaster as the spherical coffee roasters that are still used in Vietnam today.