What happens to the remaining SMM during the brewing process?

The correct choice highlights that remaining S-methylmethionine (SMM) in the brewing process is converted to dimethyl sulfide (DMS) during heating. This conversion occurs mainly during the boiling stage of brewing, where the heat causes a chemical reaction that leads to the transformation of SMM into DMS, a volatile compound.

DMS is significant in brewing because it contributes to the flavor profile of the beer; however, excessive levels can lead to off-flavors, often described as vegetal or cooked corn-like. Understanding this conversion is critical as it helps brewers manage DMS levels to achieve the desired flavor in their final product.

The other choices focus on different aspects of SMM, but they do not accurately describe the behavior of SMM during the brewing process. For instance, while some SMM might be retained in the malt, the question emphasizes what specifically happens during brewing. The idea that SMM is broken down into sugars or removed during fermentation does not align with the chemical pathways involved in brewing. Instead, the primary transformation of SMM to DMS during boiling is a fundamental aspect of brewing chemistry that brewers must control.