Yeast does in fact start to 'die' after a time. HOWEVER, if you freeze it, it will keep for 5 years FOR CERTAIN. I discovered this by accident. No kidding. I found a brick of yeast I bought at SAMS club in 2013. It wound up under some other frozen prep stuff. I forgot it was there. The expiration date was 2015. This was December of 2020. I opened it, poured it in warm water with sugar to see if it would 'activate'. I couldn't believe it. It was bubbling with life within 15 minutes. I used the entire brick to make bread and pizza for about a month. worked like it was not expired.
Yeast does in fact start to 'die' after a time. HOWEVER, if you freeze it, it will keep for 5 years FOR CERTAIN. I discovered this by accident. No kidding. I found a brick of yeast I bought at SAMS club in 2013. It wound up under some other frozen prep stuff. I forgot it was there. The expiration date was 2015. This was December of 2020. I opened it, poured it in warm water with sugar to see if it would 'activate'. I couldn't believe it. It was bubbling with life within 15 minutes. I used the entire brick to make bread and pizza for about a month. worked like it was not expired.