A type of fresh yeast, sold in dense crumbly cakes, that is used as a leavening agent for bread dough. Cake yeast is very perishable, so it must be used as soon as possible; however, it can be stored in the freezer for later use. If the cake yeast does not have a fresh scent or it is not moist and firm, it should not be used. Cake yeast is also known as, Compressed Fresh Yeast.