Can I use expired yeast? (+3 freshness tests)

In this article, we will answer the question “Can I use expired yeast?”, and how to store yeast?

Can I use expired yeast?

You can use expired yeast but it may not be as potent as fresh yeast. Yeast packets have a best before date rather than an expiration date. After the expiry, yeast can be used from 1 week to as long as 6 months. 

Yeast is a fungus that is used to ferment your dough. During fermentation, yeast produces carbon-di-oxide gas that leavens your dough when it gets trapped in the crumb structure.

When the yeast is dead, it cannot ferment your dough. Fortunately, there are ways you can tell if the yeast is still active or not. Read on if you want to know how to tell if the yeast is dead and what to do with the dead yeast.

The shelf-life of yeast

The following table shows an approximate time during which the yeast may still be active past the expiry or the best before date. If you are unsure whether to use or discard your yeast, it is recommended to perform the yeast freshness test.

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 yeast is active?

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. 

When to discard yeast?

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
  • Fresh yeast

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 t keep it alive.
Substitutes for yeast in baking

If your yeast is dead and you want to save yourself a trip to the market, try the following 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 last 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.

Conclusion

In this article, we answered the question “Can I use expired yeast?”, and how to store yeast?

References

https://www.thespruceeats.com/how-long-is-yeast-good-for-1388307

https://www.doesitgobad.com/does-yeast-go-bad/

https://www.cookist.com/expired-brewers-yeast-lets-see-how-it-can-be-used/

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