Yeast is an important component of baked goods. Its function is to activate dough fermentation and give bread a soft texture. However, when we encounter the issue of expired yeast, the answer is not an absolute no. Although expired yeast does not completely lose its fermentation ability, its activity will weaken, which means that more yeast needs to be used to achieve the desired effect. Even if the yeast has expired, it can still be used for baking dough, but the amount of yeast needs to be increased appropriately to ensure smooth fermentation.

However, if the yeast has been expired for a long time, such as more than six months, it should be used with caution. Because mutated microorganisms may breed during the expiration process, affecting dough fermentation and product quality, and may even pose potential risks to health. To determine whether the yeast has expired, you can observe whether the packaging is clumped and discolored, smell if there is any peculiar smell, or confirm its activity through actual fermentation tests. If the yeast smells sour or musty, or doesn't ferment well, it's probably expired.

In general, although expired yeast can be used for baking dough, its effect will be affected and there will be certain health risks. Therefore, for the use of expired yeast, we should give priority to safety and effectiveness, ensure that the freshness of the yeast is judged through appropriate methods, and replace new yeast when necessary.