I cannot even begin to tell you how many times I started baking something only to have my dough not rise at all, realizing the yeast has expired. It’s so disappointing, and what a waste of ingredients.
All your yeast products whether it’s in a jar or a package should be stamped with a “Best if Used by” date. Always make sure you check this date, even when you purchase the yeast, who knows it could have been on the shelf past its expiry date.
To keep your yeast fresh and longer lasting, unopened yeast packages or jars should be stored in a cool or dry place such as your cupboard. However, you can also store your yeast in the fridge or freezer. If you do store it in the freezer and need to use yeast for your baking, make sure you take out the amount you need and let it sit at room temperature for at least half hour before using.
Once your yeast package or jar has been opened, you must refrigerate the yeast or freeze it in an airtight container.
One thing to remember about your yeast, is that it is a living organism and over time it will lose activity, even if you’ve never opened the jar or package. So if you don’t bake often, buy the smaller yeast packages rather than a bit jar of yeast.
If you’ve had your yeast for a long time, and are nervous of using it, before wasting all those ingredients, you can test out your yeast. Simply take a bit of yeast and throw it in a glass with a little warm water and a bit of sugar. If it starts bubbling after a few minutes, you’re good to go, if not, throw that yeast out and get some fresh yeast.
Speaking of fresh yeast, if you’re a baker that loves to use fresh yeast, which you probably can only get from a bakery, fresh yeast can also be frozen. However, it won’t last in the freezer forever either, probably a couple months, no more. The trouble with fresh yeast is that most bakeries only sell them in big blocks like half a pound or a pound, so unless you’re ready to bake up a storm, it might not be a good idea to buy it.