Which of the following is NOT a benefit of lees contact?

• A. Aromas & flavors are enhanced
• B. Stabilizes unstable proteins
• C. Protects from oxygen
• D. Produces sulfur compounds (can be detrimental)

Answer: (D)

Lees contact ages wine on the spent yeast lees, and the breakdown products from autolysis add compounds that boost aroma and flavor complexity, improve mouthfeel with creamy textures from mannoproteins, and can help stabilize proteins that might otherwise form hazes. It can also contribute to some oxidation protection through the protective effects of those lees-derived compounds, helping preserve freshness to a degree. The idea that sulfur compounds are produced is not a benefit because these sulfur compounds, such as hydrogen sulfide, often create off-aromas like rotten eggs or burnt odors and can detract from quality. So while many favorable effects come from aging on lees, the production of sulfur compounds is a drawback rather than a benefit.