How Long Does Yeast Last? Does Yeast Go Bad?

Do you have a pack of dry yeast that you bought a while ago and it’s still sitting in the kitchen or pantry cabinet unopened and untouched? Also, the last time you looked at it, the best-by date put on the pack was nearing. You now want to use it to bake some homemade pastries but are not sure whether the yeast is still good for use. Can yeast go bad?

Or maybe you choose to buy a fresh batch of yeast for your baking needs instead. Then you become busy and forget about it and it stays in the fridge for about two weeks. Is the yeast still good for use or are you supposed to discard it?

Bad yeast in most cases (i.e., the one that has mold and is not safe for consumption) is not very common, also there’s the issue of effectiveness. While the chemistry around it is quite different, the general idea happens to be the same as the potency of baking powder.

If your yeast cannot make your bread soft and fluffy or rise it’s of no use. The most vital thing when it comes to yeast is knowing that it will perform its job. Fortunately, there are a number of ways in which one can test it and find out whether it is still active and safe to use. If you want to know more about the shelf life, storage as well as proofing and going bad of yeast, read on.

How To Store Yeast

There are two different kinds of yeast that can be found in the market: fresh yeast and dry yeast. The latter is more popular and will last for a longer time. However, the former is said to be able to produce dough of a better quality and is normally used by cooking enthusiasts and in artisan bakeries. Let’s look at dry yeast first.

Dry yeast is numerous granules of yeast that are in a dormant state, waiting for activation. An unopened pack containing dry yeast should always be stored in a cool and dry place. You can store it in a kitchen cupboard or in the pantry away from heat and water.

Once the package is opened, you can then refrigerate or freeze the remaining one. Dry yeast can easily get spoiled when it comes into contact with heat, air or moisture and it will need to be refrigerated once the package is opened.

Not that you’re not supposed to place the package as it into the fridge because there is moisture there and it can easily get into the yeast. The yeast should instead be transferred to a resealable freezer bag or an air tight container.

Note that when you need to use the yeast for baking, take as much as you need and immediately put whatever is remaining back in the fridge for further storage. You can find fresh yeast in the refrigerated section of the supermarket and it should always be stored in the fridge.

Just like when using dry yeast, cut off the needed amount of fresh yeast (like your recipe suggests) and return the remaining one back into the fridge.

How Long Does Yeast Last?

Dry yeast comes inclusive of a sell-by date that can be found on the packaging. Just like most products that have a sell-by date, they can stay for a longer time past the suggested time, same applies to dry yeast.

Normally, if the unopened yeast is almost nearing the suggested date, you have to test for the effectiveness of the product before you can use it to bake bread. However, once it is opened, the remaining yeast has the possibility of retaining its effectiveness for at least four months when it is stored in the fridge and for about six months when stored in the freezer.

Of course, the dates provided are just rough estimates. It’s possible for yeast to lose its effectiveness even earlier than the date given.

Fresh yeast in essence is just a living organism that will remain active (and thus potent) for at least two to three weeks from the when it was produced.

A pack of fresh yeast normally comes with a use-by date, and you’re not supposed to expect the yeast to remain potent for a longer time. Of course, there are instances where it can stay for longer, but just like dry yeast it may become inactive at a much earlier time.

If you will not be able to use the whole package within a short time, then freezing the fresh yeast is the best solution to the problem.

Note that the durations provided above are only rough estimates. Yeast usually maintains its potency for a much longer time however, it is not the norm.

How To Tell If Yeast Has Gone Bad

The symptoms of dry yeast getting spoiled are the same as those of other dry ingredients such as flour. This means that when it begins forming solid chunks, clumping together or any other signs of organic or water growth.

When it comes to fresh yeast, the symptoms are dying out, discoloration and any indication of mold. If you come across any of the signs, do away with it. Note that your yeast will smell and look perfectly normal. If this isn’t the case and the product is almost at the end of its period of effectiveness as stated earlier, confirm whether it is still active before you can proceed using it to bake bread or other pastries.

How To Test Yeast Effectiveness

When proofing your yeast, ensure that the dough you’re preparing will transform from this (freshly mixed dough for bread):

To this (the same dough when left for 90 minutes to rise):

Confirming your yest effectiveness (also known as proofing the yeast) is performed in the same manner for both fresh and dry yeast. All you need is some sugar and warm water to do so.

When dealing with dry yeast, you’ll require a packet of dry yeast, a ¼ cup of warm water (at about 40 degrees to 46 degrees C, or 105 degrees to 115 degrees F for it to rise well because 140 degrees F or 60 degrees C and more will kill the yeast) and 1 teaspoon of sugar. Mix the ingredients properly then let them sit for 10 minutes. If your mixture foams up to almost a ½ cup level, then it is potent enough to be used.

When dealing with fresh yeast (also known as cake yeast), most recipes include the proofing process and when they don’t, you can include it by yourself.

Begin by dissolving a teaspoon of sugar into a ½ cup of milk or water (90 degrees – 100 degrees F, or 32 degrees – 38 degrees C). Add your fresh yeast, mix it properly the let it sit for at least 10 minutes. Foam should have formed after the 10 minutes rest. If that doesn’t happen, discard the yeast. If there is enough foam, you can proceed to ass the other ingredients required for the dough.

Berry