How Long Does Yeast Last? 

Sealed, unopened dry yeast keeps about 2 years. Chilling extends its life span, which is why it’s best to store dry yeast (unopened and opened!) in the refrigerator or freezer. Always look at the best-before date before purchasing a bag or jar of yeast, then buy the freshest one. Opened active and instant dry yeast will last four months in the refrigerator and up to six months in the freezer. Fresh yeast (also called cake or compressed yeast) will last up to two weeks in the refrigerator and should not be frozen.

How to Store Open Yeast

Keep it airtight. Exposure to air will shorten the life of yeast. If the yeast is in an open envelope, fold down the top and seal the envelope with tape, a paper clip, or a rubber band. If it’s in a bag, press as much air out of the bag as possible, tape or rubber band it up, and then seal it in a zip-top bag. You can also transfer the yeast to a glass jar with a tight-fitting lid. Don’t forget to label! Before storing, label the bag, container, or jar with the date it was opened or the use-by date (four months out if you’re storing it in the refrigerator or six months out if you’re storing it in the freezer).

Why You Should Store Yeast in the Freezer

Some manufacturers and baking experts recommend against freezing dry yeast, because it can kill off cells and make it less active. However, that has not been our experience. Many of us at Simply Recipes freeze dry yeast and witness no ill effects when we use it later on. It’s definitely the go-to method around here, especially for busy bakers who like to buy yeast in bulk!