Coffee

Coffee is a relatively young beverage that has only been known about since the 17th century. Initially consumed by the aristocracy, coffee has developed since the early 20th century into one of the world’s most popular beverages and is now part of our daily routine and lifestyle. It also represents a major source of income for many coffee-producing countries and is a significant business sector in consumer countries. The triumph of this beverage may have been driven by various factors, but there is no doubt that its unique flavor is the prime reason for its amazing success. Here we will review current knowledge on the aroma of coffee from a chemical and analytical perspective and outline future trends. It is believed that most coffee aroma compounds have already been identified and quantified. Yet little is understood about how these aroma compounds are generated from green coffee precursors during roasting. A true definition of the aroma of freshly roasted and/or brewed coffee is very elusive and some aroma compounds start to degrade the moment they form. Furthermore, research on interindividual differences in the sensation and perception of coffee aromas is still in its infancy. After reviewing our current knowledge on coffee aroma compounds, we will outline recent developments in time-resolved analysis in three fields: 1. Aroma formation during roasting 2. Aroma extraction during espresso preparation and 3. In-mouth release during consumption. Finally, we will address predictive models for sensory profiles derived from instrumental measurements – possibly the holy grail of aroma sciences.