From Bean to Cup: The Story of Coffee Production

While still green, coffee is shipped from mills to roasting plants in jute or burlap sacks. After it's heated to a high temperature, coffee expands in size, loses 20 percent of its weight, and develops a dark, toasty aroma. Unlike single-origin coffees, roasting of coffee blends may be manipulated slightly from year to year in order to maintain a consistent flavor year over year.