Coffee. The fragrant morning pick-me-up that we all take for granted. No matter if you push a button on a home coffee machine or pull up to the drive-thru, getting a good cuppa joe is a mindless routine. The science behind coffee? Not so simple.
Of course, good coffee starts with the bean. (Note: Factors like field altitude, soil composition, and harvesting/drying methods have a big impact on the final quality of the coffee bean.) But, in my opinion, a lot of the really cool food science stuff happens when the bean is roasted. During roasting, coffee beans are exposed to heat, and the Maillard reaction begins. Reducing sugars react with amino acids in the bean, and those familiar aromas, color, and flavors begin to develop. (For another example of the Maillard reaction check out “Why Baked Goodies Brown.”) The roasting process initiates other chemical reactions as well, which can alter the volatiles in the bean. This is how manufacturers vary the flavor of coffee – time and temperature during roasting can mean the difference between a lovely dark, aromatic flavor, and a burnt, bitter roast that tastes like day-after brew.