Coffee Roasters are machines used to transform the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to change in taste. 

Coffee tends to be roasted close to where it will be consumed, as green coffee is more stable than roasted beans. The vast majority of coffee is roasted commercially on a large scale, but small-scale commercial roasting has grown significantly with the trend toward "single origin" coffees.