Does nutritional yeast expire or go bad?

Your question: is it good to use. My answer: yes.

1. You say it smells and looks normal. That's an important clue.

2. We are talking about a dry product. No moist means no growth, no toxins...

3. Best before date. Wikipedia:

Most shelf life dates are used as guidelines based on normal and expected handling and exposure to temperature. Use prior to the expiration date does not necessarily guarantee the safety of a food or drug, while a product is not always dangerous nor ineffective after the expiration date

I'm not sure about an expiry date, but I have been told by an employee at a health food store to keep it in the dark as it is negatively affected by prolonged exposure to light.

Also, growing up, my mom always kept it in the freezer and I do likewise now. I use it straight out of the freezer, and some that I currently have had in there for at least a year in a tightly closed plastic bag stil tastes great when I use it.

As mentioned by others, it is not active like bread yeast, so that will prolong its life. Also, it seems quite salty to me, so whatever is adding the salty aspect to it may also be helping preserve it.

Nutritional yeast is different from bread making yeast. It s deactivated thus it does not expire like regular yeast.

Nutritional yeast can turn quite bitter tasting if stored at room temperature for more than a a week or two. So I keep it in the fridge and it will last a few weeks, sometimes a few months (depends how long the seller has stored it before I came along, I guess?). I let my tastebuds be my guide.

Also, the fresher it is, the lighter in color it seems to be - but not always. Also, it seems more flaky and has a "lighter" tang when fresh, compared to a little more matted, and sharper taste when it's been stored awhile (effect of moisture in the air?).

Hope that helps.

I was looking for the same information about storing nutritional yeast and found some good info here: http://www.ehow.com/how_7849400_store-nutritional-yeast-flakes.html.