Electronic noses based on an array of differently coated quartz microbalances (QMBs) yield information about the components of food aromas, which can be differentiated upon analyzing the data using contemporary pattern-recognition programs. Even single lead substances can be determined quantitatively against the background of similar carbonyl components. Once properly calibrated, even complicated odors can be analyzed in this fashion with considerable accuracy, whereby it is typically sufficient to focus on one or a few lead components. In this study, this QMB-based method has been applied to monitor the ripening process of Emmental cheeses, during which the concentration of 2-heptanone changes characteristically. Following the development of the 2-heptanone concentration over time not only allows us to distinguish different states of ripening process of Emmental cheese.