What process stops the formation of DMS in wort?

The correct answer is the quick chilling of wort, as this process significantly reduces the formation of Dimethyl Sulfide (DMS), a compound often associated with undesirable flavors in beer.

When wort is boiled, DMS is formed from its precursor, S-methylmethionine (SMM), which is present in malt. Prolonged boiling allows the DMS to escape due to its volatile nature. However, if the wort is not cooled quickly after boiling, DMS can reabsorb back into the liquid. By employing rapid chilling methods, such as an immersion chiller or plate chiller, the temperature of the wort is dropped swiftly, minimizing the time DMS has to convert back into its more volatile form. This process effectively helps to maintain lower levels of DMS in the finished beer.

Other options, while they may influence different aspects of brewing or beer quality, do not address the specific concern of DMS formation as directly as quick chilling does. For instance, coolship fermentation is more about traditional techniques for developing flavor profiles in certain styles rather than controlling DMS. Proper aeration of wort is essential for yeast health and fermentation efficiency, but it does not directly impact DMS levels. Whirlpooling, while it helps in clar