Langstaff, a professional in sensory analysis, is often approached by wine enthusiasts who notice unpleasant odors in their wine. These off-flavors, or defects, provide essential clues about the mistakes made during production. By identifying specific scents, he can diagnose the source of the problem, whether it's with the ingredients or the process used in fermentation.

For instance, if an olive oil has notes reminiscent of straw or hay, it indicates a problem with the olives being overly dried. Similarly, a beer carrying a hospital-like aroma hints at possible usage of chlorinated water in production. There's also a specific reference to certain flavors in wine that point toward spoilage caused by Brettanomyces yeast, exemplifying how sensory cues are vital for understanding quality in food and beverages.