A high level of which compound often leads to a matchstick smell in wine?

The presence of a high level of hydrogen sulfide in wine is commonly associated with a matchstick smell, which is often described as a rotten egg or cooked cabbage aroma. Hydrogen sulfide (H2S) can be produced during fermentation under reductive conditions, where yeast is deprived of oxygen. This compound can be particularly prevalent in young wines or wines that have been improperly stored.

Utilizing the other compounds mentioned, Brettanomyces is a type of yeast that can impart a more earthy, barnyard-like character to wine, while sulfur dioxide is primarily used as an antioxidant and preservative and is not directly linked to a matchstick aroma. Ethylene is a plant hormone involved in the ripening of fruit but does not contribute to wine aromas in this context. Hence, hydrogen sulfide is indeed the compound typically responsible for the matchstick smell in wine.