What temperature will kill yeast?

In this brief article, we are going to answer the question “what temperature will kill yeast?”. We will also discuss what temperature is ideal for proofing yeast. In the end, we will discuss what are the appropriate temperature recommendations.

What temperature will kill yeast?

Temperatures of 140 degrees Fahrenheit or above in the water will kill yeast.

If the water temperature is over 120 degrees Fahrenheit, the yeast will start to die regardless of the kind used. 

When the temperature of the water reaches 140 degrees Fahrenheit or above, the yeast will die off altogether.

Using the wrist-test as a guide, we may identify that temperatures of 120 degrees Fahrenheit seem hot while temperatures of 140 degrees Fahrenheit are unbearable. The wrist test isn’t usually reliable, thus a candy thermometer may be used instead.

If it’s not only warm but scorching or too hot for the yeast to survive unfortunately. Similarly, yeast won’t activate if it’s too chilly outside.

What temperature is ideal for proofing yeast?

Yeast is an active, single-cell fungus creature. There are about 160 kinds of yeast, and they may be found both within and outside of the human body.

Dry Yeast

Dry yeast won’t work if the water temperature is too low. Additionally, if they do awake, they may secrete a chemical that prevents gluten from being formed. 

However, if the water becomes too hot, the small organisms will perish. When proving dried yeast, heat the water between 105 and 115° Fahrenheit is optimal.

Although most recipes call for live yeast, which requires temperatures over 95 °F. This temperature might not have been hot enough to activate dry yeast. 

After you pour it into the bowl and dissolve the sugar, it will cool just enough to be the ideal temperature for integrating and activating your bread liveners.

If you don’t know whether the water in your house is the proper temperature? The wrist test may be used to check for this. 

Several drops of water on the inside of the wrist is a good way to start. In the same way that you would feel at ease in a warm and cozy environment, your yeast would do the same.

Fresh, Live Yeast

Proofing temperatures should be around 95 and 100 degrees Fahrenheit if you’re using active fresh yeast. 

For one thing, fresh yeast also known as cake yeast doesn’t have to be dissolved in water before use. Combining it with water is all that’s needed to start its feeding and growth process.

Instant Yeast

There is no need to proof Instant Yeast, also known as Rapid Rise Yeast, in hot water when using it. Since this yeast is combined with flour before being introduced to water, the recommended cooking temperatures are much greater, ranging 120 – 130 degrees Fahrenheit.

However, this yeast shouldn’t be proofed, you may do so if you have any doubts that it is sufficiently active. 

The proofing process is the same as that used for active dry yeast. Another possible explanation for the tolerance of elevated temperatures is that the flour is often stored at temperatures close to room temperature.

What are the appropriate temperature recommendations?

The recommended water temperatures for testing the yeast are listed below to give you a rough estimate.

Yeast fermentation is inhibited by cold water, and at -4 degrees Fahrenheit, that’s not going to happen.

Yeast’s growth rate and viability will be stunted if you use water between 68 and 104 degrees Fahrenheit.

The optimal temperature range for yeast growth and multiplication is 68 to 81 degrees Fahrenheit in water.

It is generally agreed that yeast growth is best stimulated in water at a temperature of 79 degrees Fahrenheit.

The fermentation process works best with water between 81 and 100 degrees Fahrenheit.

To get the most out of your fermentation process, use water heated to 95 degrees Fahrenheit.

Yeast can only survive in water below 140 degrees Fahrenheit. All the yeast will die at these temperatures.

These are just rough estimates, and they may be dependent on whether you use activated dry yeast, live yeast, or rapid rise yeast. 

Simply said, yeast grows rapidly in warm water, slows down or stops altogether in cold water and eventually dies in hot water. 


In this brief article, we answered the question “what temperature will kill yeast?”. We also discussed what temperature is ideal for proofing yeast. In the end, we discussed what are the appropriate temperature recommendations.