Off-Flavors
Unfortunately sometimes your beer has a ‘bad’ the aroma or taste that can remind of what? For an example, sulfur or bad eggs.
There are many off flavors in beer but only a handful of very common ones. The majority of these off flavors in beer are naturally occurring. Some are even necessary in certain beers and a few are actually characteristic of specialist styles. They become off flavors only when present in high concentrations and when inappropriate for the style.
A common language has been devised to describe beer flavors and brewers throughout the world have agreed on a terminology that is used for beer. Whether a flavor is regarded as undesirable or not depends upon several factors: the beer style, the sensitivity of the taster, and the consumer’s expectation.
Sources Referenced: Beer Judge Cert. Program (BJCP), Thomas Barnes'Beer Fault Guide