What is one significant chemical change that occurs during the boiling of wort?

During the boiling of wort, one significant chemical change is the coagulation of proteins. This process is crucial in the brewing of beer as it helps to clarify the wort and improve the overall stability and flavor of the final product.

As the wort is heated, heat denatures the proteins, causing them to unfold and aggregate. Specifically, proteins derived from barley and other grains, as well as from hops (like polyphenols), will coagulate together. This coagulation results in the formation of a substance known as the "hot break," which consists of solids that can then be separated from the liquid post-boil.

Additionally, proper protein coagulation during boiling assists in preventing haze formation in the finished beer, which is important for both visual appeal and quality. Although other options mention processes that are part of the brewing cycle, such as fermentation initiation or yeast activation, these occur after the boiling process and are not direct chemical changes involved in the boiling of wort itself. Oxygen infusion can happen similarly but is generally not a desired action during boiling, as it can lead to oxidation and negatively affect beer flavor.