Yeast Shelf Life & Storage
Be good to your yeast, and it will have good performance in your bread! Remember that yeast is a living organism, and its shelf life and freshness is largely determined by how the yeast is stored. Yeast activity is greatly reduced when it is exposed to air, moisture, and/or warmth. Learning the correct way to store your yeast will keep it fresher longer.
Check the Best if used by date on your yeast package, and use the Yeast Freshness Test if you are unsure of its activity.