How Long Does Yeast Last? Can It Go Bad?

Not everyone finds it easy to bake with yeast. Many people are afraid that it simply will not work and all their effort will be in vain. Additionally, the rest of the ingredients in the recipe will go to waste. To prevent this from happening, there are a few things you should know about yeast.

How long does yeast last and can it go bad? Yeast does have a limited shelf life. It may vary depending on the yeast variety you are using. Fresh yeast, for example, has a short shelf life. It should always be refrigerated and used until its ‘Best by’ date. The shelf life of dry yeast is comparatively long. Once opened, it lasts around 4 months in the fridge and 6 months in the freezer.

In this article, you will learn not only about the shelf life and storage conditions of yeast but also how to test its potency when you are not sure if it is still good or not.

After gathering all the necessary intel, you might want to check out some recipes that include yeast. (zucchini pasta salad/summer squash, spelt focaccia, red pepper tomato soup).

In our food substitutes section you’ll find an extensive article on instant yeast substitutes (plus bonus info on DIY yeast), in case you don’t feel ready working with it yet or face any problems during the process.

Does Yeast Go Bad?

 

Yeast can be a tricky ingredient to work with especially for those who don’t use it often. In fact, it seems so intimidating to some people that they specifically choose recipes that don’t call for yeast.

But it is quite easy to use when you get a few things right and can differentiate between different types of yeast. In general, there are two types of yeast – dry yeast and fresh yeast.

While many people stay away from recipes with yeast, others use it with no fears. And these people, in their turn, get confused about the right way of storing yeast.

The thing is, there is always a misconception that dry products last long. But what many people don’t know about yeast is that it may seem okay, with no mold or bugs. But it may not be effective. Yeast that has lost its effectiveness is like baking powder that is expired and won’t cause your baked goods to rise.

So, yeast does go bad. It doesn’t usually mold or anything of the kind. But it does lose its efficiency. And once it happens, you need to discard the yeast as there is simply no way that it will do your cakes or bread any good.

How to Store Yeast?

 

As mentioned earlier, there are two types of yeast, dry and fresh. Dry yeast is widely popular. One of the reasons why many people choose it over fresh yeast is that it lasts longer, i.e. stays effective longer.

No matter which type you choose, yeast should be stored properly in order to maintain its potency.

An unopened package of dry yeast can be stored in the pantry or somewhere cool and dry. It will keep well at room temperature or below. The key is keeping it away from humidity and direct sunlight.

An opened package of dry yeast can’t go back to the pantry. It should be stored in the fridge to prevent the yeast from losing its efficiency. But if you store dry yeast in the fridge in its original packaging, it will quickly deteriorate and lose its potency.

Put the opened package of dry yeast in a plastic bag and seal it tightly. This way you will protect it from air and water.

Fresh yeast is sold in stores refrigerated. Thus, you should store it in the fridge as soon as you bring it home, even if you haven’t opened the package yet.

Every time you need to use yeast and it is stored in the fridge, don’t take the whole package out. Take as much yeast as you need and put the rest back into the fridge immediately.

Can You Freeze Yeast?

 

Freezing is a great way to extend the shelf life of products, and yeast is not an exception. What is important to know is that it is only dry yeast that you can freeze.

Freezing doesn’t ‘deactivate’ the yeast as one would expect. Just on the contrary. It puts them in a ‘waiting mode’.

All you have to do is to transfer yeast into an airtight container. You can freeze dry yeast in its original packaging if it comes in a plastic jar and has a tightly sealing lid. For safety reasons, you can put the jar in a zip-top bag to prevent air from getting to the yeast.

Using frozen yeast is easy. Simply scoop the required amount and put it in the liquid that the recipe suggests. This way you will wake the cells right up. Don’t forget to put the jar with the yeast back into the freezer.

People who have tried freezing dry yeast report that it remains efficient for months. Thus, freezing dry yeast is a great option for those who don’t use it often.

How Long Does Yeast Last?

 

Like any other product, yeast also comes with an expiration date. There is always a ‘Best by’ date on dry yeast. As you may know, in many cases this is simply the manufacturer’s estimation of how long the product will maintain its best qualities. Unfortunately, this is not the case with yeast. Once it is expired, it is expired.

Even if the yeast hasn’t reached the ‘Best by’ date indicated on the label, it may have lost some its effectiveness. So, when buying yeast, make sure there is enough time until it reaches the date on the label.

Once the package with dry yeast is opened, you should use it within 4 months. Remember that you have to store it in the fridge. Otherwise, the yeast will turn out ineffective.

Dry yeast stored in the freezer has a shelf life of 6 months.

If you have bought a package of dry yeast and never opened it, use it until its ‘Best by’ date. If you have been keeping it in proper conditions, the yeast is almost certainly potent.

As for fresh yeast, it should always be stored in the fridge and be used until the expiration date on the label. You can’t freeze active yeast to extend its shelf life.

Signs That Yeast Has Gone Bad

To detect bad dry yeast, inspect the texture. If it is clumpy or there are chunks in it, it is possible that it has been exposed to moisture or humidity and has gone bad.

As far as fresh yeast is concerned, see if it has dried out or changed its color. Mold is another indicator that it is high time you discarded your package with fresh yeast.

But even if you look at the yeast and it seems fine, it is always good to test its effectiveness before using it. This is especially important if you have had the package with yeast for a few weeks.  

How to Proof Yeast?

 

Testing the effectiveness of dry or fresh yeast is easy. All you need is some water and sugar.

To test dry yeast, pour 2¼ teaspoons of yeast into 60 ml of water. Add a teaspoon of sugar. Make sure the water is not too hot. If the temperature of the water is higher than 140°F, the yeast will not work as its cells will simply die.

Leave the mixture aside for around 10 minutes. If it becomes foamy and rises, then your dry yeast is still good to use.

To test fresh yeast, crumble some of it into a mixture of 120 ml of warm water (milk) and a teaspoon of sugar. Leave for 10 minutes to see how the yeast reacts. If it bubbles and foams up, then you can go ahead and add it to the rest of the ingredients.

Some recipes that use yeast include the yeast proof test too. If the recipe you are using doesn’t, adjust the amounts of ingredients used in the recipe taking into account the amount of liquid and sugar you have used to proof the yeast.