According to Mary Roach in "Gulp: Adventures on the Alimentary Canal," the distinction between a professional nose and an ordinary one lies in the skill of discerning and identifying different aromas rather than just recognizing their presence. This ability allows professionals, such as sommeliers and perfumers, to dissect complex scents into their individual components, enhancing their appreciation and understanding of food and drink.

Roach emphasizes that while sensitivity to scents is important, the true expertise is in the refined ability to analyze and articulate what each aroma contributes to the overall experience. This level of expertise elevates the appreciation of flavors, offering insights into the intricate relationship between aroma and taste.