Does yeast go bad? (+3 steps to check)

In this article, we will answer the question “Does yeast go bad?”, and how to store yeast?

Does yeast go bad?

Yeast going bad because of fungal invasion is rare. However, if stored incorrectly, yeast can lose its potency. Impotent yeast cannot make your dough rise and it is of no use. Read on if you want to know how to check the potency and how to store yeast correctly.

How long does yeast last?

The following table shows an estimated half-life of different types of yeast under different storage conditions.

In the refrigeratorIn the freezer
Past printed datePast printed date
Dry active yeast(unopened)2-4 months4 months
Cake yeast(unopened)1-2 weeks2-3 months
Dry active yeast(opened)4-6 months6 months
Cake yeast(opened)4 monthsNot recommended

How to tell if the yeast has gone bad?

If the yeast starts to clump together and/or appears discolored, discard the yeast immediately. In case of any apparent discoloration and mold growth, it is recommended to toss the yeast in the bin.

If the yeast looks and smells fine but is past its best before, better perform the freshness test before adding it to your dough.

How to store yeast?

There are two types of yeast that are used frequently by home bakers and commercial bakeries namely:

Dry yeast is quite shelf-stable due to which an unopened packet of dry yeast will be good in the pantry if kept away from stove heat, direct sunlight, and moisture. As soon as you open the packet, the dormant yeast granules become vulnerable to spoilage. Therefore, it needs to be refrigerated.

You cannot refrigerate dry yeast in an open packet. The humid environment of the fridge will destroy the quality of yeast. To overcome this, transfer the yeast to a zip-locked freezer bag and store it.

Fresh yeast, also called cake or compressed yeast is more susceptible to spoilage. It is sold in refrigerated form and must be stored in the refrigerator to keep it alive.

How to tell if yeast is still potent?

You cannot tell by looking at the yeast if it is dead or not. Perform the test below to check if the yeast is active.

  1. In a cup, take ¼ cup lukewarm water. It is best to check the temperature of the water using a thermometer and make sure it lies between 110-115°F. A temperature higher than 120°F will destroy your yeast. A temperature lower than 110°F will not be able to activate the yeast to its full potential. To the water, add 1 ¼ tsp of yeast and 1 tsp of granulated sugar.
  2. Give it a stir until yeast is dissolved completely. Wait for 10-15 minutes.
  3. If the yeast forms bubbles or foam on the surface and you smell a strong yeasty aroma, the yeast is active. If not, the yeast is dead.

This proofing test can also be performed with a small amount(walnut-sized) dough. 

Other FAQs about Yeast which you may be interested in.

How much is a package of yeast?

How many teaspoons are in a packet of yeast?

How to propagate yeast

How to proof dry active yeast?

  1. In a bowl, add 1/2 cup of warm (105° to 115°F) water, 1 tsp sugar, ¼ ounce yeast. Stir and wait for 10 minutes.
  2. If the mixture becomes foamy, the yeast is active.

Substitutes for yeast

Baking soda and an acid

Replace the yeast with the same amount of baking soda and an acid (citric acid, lemon juice, vinegar, cream of tartar, buttermilk, etc). For example for 1tsp of yeast, add ½ tsp baking soda and ½ tsp acid. Baking soda, when exposed to acid and water, reacts to forms CO2 that leavens the dough.

Double-acting baking soda performs leavening once when exposed to water and again when exposed to heat. Put the baking soda at the end if it is single-acting.

Baking powder

Substitute the yeast with an equal amount of baking powder. Baking powder is made up of baking soda and acid. Baking powder is double-acting and performs leavening twice; first when it comes in contact with the liquid ingredients of the recipe and the second time when you put the dough in the oven exposing it to high temperature.

How to proof cake yeast?

  1. In a bowl, add 1/2 cup of warm liquid (90° and 100°F) and 1 tsp of sugar.
  2. Stir  the crumbled cake yeast into the mixture to dissolve it.
  3. After 10 minutes, if the liquid gives off a yeasty smell and becomes foamy on top, it is active. If not, it is dead.


In this article, we answered the question “Does yeast go bad?”, and how to store yeast?


Hello, I'm Sana Ameer. I'm a student of Food Science and Technology at UVAS. I like to bake and I aspire to become a Food blogger.