Wine connoisseurs can easily discriminate a dry red wine, such as Cabernet Sauvignon, from a fruitier red, like Pinot Noir. Scientists have long linked the "dryness" sensation in wine to tannins, but how these molecules create their characteristic mouthfeel over time is not fully understood. Now, researchers reporting in ACS' Journal of Agricultural and Food Chemistry have found that tannin structure, concentration and interactions with saliva and other wine components influence the perception of dryness.