What compound found in barley and wheat produces clove flavors during fermentation?

Ferulic acid is a phenolic compound that occurs in the husks of barley and wheat and plays a pivotal role in brewing. When yeast ferments the sugars in malted grains, ferulic acid can be converted into 4-vinyl guaiacol, which imparts distinct clove-like flavors and aromas to the beer. This is particularly evident in certain yeast strains that exhibit this characteristic during fermentation.

In contrast, isoamyl acetate, while associated with banana flavors, is not responsible for clove notes. Dimethyl sulfide (DMS) has a different flavor profile, commonly contributing cooked corn or vegetable aromas. Diacetyl is known for its buttery flavor, which is also not related to clove-like characteristics. Thus, the unique fermentation characteristics of ferulic acid specifically contribute to the development of clove flavors in certain beer styles, making it the correct choice in this context.