Does nutritional yeast go bad? What are the signs of expiry? How to do store nutritional yeast to make it last longer? Like all foods, nutritional yeast can go bad too. Nutritional yeast does last much longer than instant active yeast. Active yeast, also known as instant yeast, expires within a few months of opening the packet, while nutritional yeast lasts 2 years if stored properly. Nutritional yeast and active yeast are actually two different products with two different purposes. Active yeast is primarily used in baking breads while nutritional yeast is valued for its nutritional purpose. Rich in Continue Reading