Roasting coffee transforms 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. Unroasted beans contain similar if not higher levels of
acids,
protein, sugars, and
caffeine as those that have been roasted, but lack the taste of roasted coffee beans due to the
Maillard and other chemical reactions that occur during roasting.