People who start their mornings by pouring cream and sugar into a steaming mug of coffee are usually trying to mask the beverage’s bitterness. But the reason coffee makes us pucker has eluded scientists for decades. Now, researchers have narrowed the search by identifying two chemical compounds responsible for bitter taste in coffees ranging from mild breakfast blends to intense espressos. According to work presented here at the annual meeting of the American Chemical Society, it turns out that the roasting process–not the raw beans–produces these compounds, a finding that could open the door to improved methods for processing coffee beans.
A cup of coffee is a complex brew of more than 30 chemical compounds that contribute to its taste, aroma, and acidity. Since the 1930s, scientists have separated and identified numerous chemicals responsible for many of the sensory components of a cup of joe, but few have investigated those that produce bitterness.