What compounds can be used to kill yeast during the fermentation process?

The use of sulfur dioxide and grape spirit as agents to inhibit yeast activity during fermentation is rooted in their respective properties. Sulfur dioxide is widely recognized in winemaking for its antimicrobial and antioxidant effects. It can effectively kill or inhibit the growth of yeast, which is crucial for managing fermentation and ensuring that the desired microbial balance is maintained. This helps prevent unwanted fermentation, spoilage, and off-flavors in the wine.

Grape spirit, which is essentially a high-proof alcoholic distillate made from grapes, can also contribute to killing yeast. The high alcohol concentration can create an environment that is inhospitable for yeast, effectively stopping fermentation when intended.

In contrast, the other options do not possess the same ability to inhibit yeast effectively during fermentation. While ethyl alcohol can result from fermentation and may have some inhibitory effect at high concentrations, it is not primarily used to kill yeast. Water does not have any inhibitory effect on yeast and rather serves as a medium. Sugars and acids are typically part of the fermentation process and can promote yeast activity rather than inhibit it. Lastly, carbon dioxide is produced as a byproduct during fermentation and does not kill yeast; nitrogen is essential for yeast growth and metabolism. Thus, sulfur dioxide and grape spirit are the correct