Which of the following off-flavors is considered acceptable in lagers?

Slight sulfur is considered acceptable in lagers due to the typical fermentation conditions and yeast strains used in lager brewing. Many lager yeast strains, particularly those in the Saccharomyces pastorianus family, can produce small amounts of sulfur compounds during fermentation. These compounds can contribute to the overall character of the beer without being overpowering, often perceived as a pleasant aspect resembling flint or matchstick. In certain lager styles, this slight sulfur aroma is accepted and may even be desirable, especially in traditional German lagers.

Other off-flavors mentioned, such as diacetyl, esters, and phenols, are generally not accepted in lagers. Diacetyl, which has a buttery flavor, is particularly undesirable in lagers and indicates poor fermentation management. Esters, which can contribute fruity notes, are also typically frowned upon in lagers, as they detract from the clean and crisp profile that is characteristic of these styles. Similarly, phenolic off-flavors are typically associated with the use of specific yeast strains or poor fermentation practices and are generally not desirable in a lager, particularly when aiming for a clean and refreshing beer profile.