Natural
roasted coffee beans. Green
coffee beans are first roasted (which makes them turn brown), and then ground in the process of making
coffee. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell and density. Unroasted beans contain similar acids,
protein, and
caffeine as those that have been roasted, but lack the taste.
Photo credit: MarkSweep