so I was trying to make cinnamon rolls about a month ago and used the active dry yeast exp 9/21 that was in my fridge. And it was proofing. Then I bought another one which exp date was 10/21. I'm trying to do the same thing and it's not proofing. I'm not sure what's wrong. Please help. Thank you
Yeast is a living thing. If your yeast was exposed to conditions that killed or damaged it, most likely extreme temperatures, you will not get the results you expect regardless of the date stamped on the container. On the other hand, just because it's past the date on the jar, the yeast hasn't necessarily kicked the bucket yet. Unfortunately, yeast can't read.
Related: Does active dry yeast really expire?