How Do You Know If Yeast Has Gone Bad?
There are a few signs to look out for to know if yeast has gone bad. The first is a change in color; if the yeast has turned a darker shade or appears gray or brown, it has gone bad. Another sign is a change in smell; fresh yeast should have a slightly sweet and yeasty smell, but if it has a sour or rotten smell, it has gone bad. Additionally, if the yeast does not activate or rise when added to a recipe, it may also be a sign that it is no longer fresh.