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How Hot Is Too Hot For Yeast?
It doesn’t really matter what kind of yeast you are using; for every type of yeast once the temperature reaches 120 degree Fahrenheit, the yeast will start to die. It will be completely killed off when the temperature reaches 140 degree Fahrenheit as it would be too hot for yeast.
If you are baking bread, you know the ideal temperature to get the yeast activated is around 100F, or 38C. The temperature that the yeast will activate depends on a few factors, like what kind of flour is used and how much water is added.
Regardless of which yeast you are using, water temperatures at 120 degrees F. or higher will kill the yeast. In the worst cases, chilly water that is close to 4F is unable to ferment the yeast.
If using a live yeast, a temperature of 95degF would be fine, but it may not be warm enough for a dry strain. While 95 degrees is a nice temperature at which yeast can reproduce, it is not really hot enough for proofing an active dry yeast.
| Worst temperatures | Best temperatures |
| Water temperatures at 120°F. or higher will kill the yeast. | The ideal temperature to get the yeast activated is around 100°F. |
| Chilly water that is close to 4°F is unable to ferment the yeast. | 95°F is a nice temperature for yeast reproduction but it is not hot enough for proofing an active dry yeast. |
For instance, active dry yeast deteriorates and stops working if you take it above 115 degrees F. Once active (only for active dry yeast), proofing yeast-based doughs at lower temperatures takes longer to raise. It is important to note that if you leave your dough unattended for a prolonged time, yeast will be exhausted.
If you’re interested in Can You Use Regular Yeast In A Bread Machine, then check out this article.
If using cold water, expect to put the dough into the refrigerator and let it knead for several days (typically, a nice big rise takes three days). Yeast needs warmer temperatures to be activated, so when putting the dough in for rising, be sure to keep it sitting around 70-80 degrees F, so the yeast can function optimally.
When using yeast for the products of dough, you need to know that it will instantly die if your water temperature to mix with goes over 140 degrees F. While fresh yeast does not have to dissolve, it will begin to feed and multiply if exposed to warmer water temperatures of 95F to 100F. As yeast sits in the sugary water, it will start dissolved and will be active, or awake. Sprinkle yeast starter in lukewarm water with some sugar if using, and allow to bloom for several minutes.
To know more about yeast fermentation, check out my another article on that! What Temperature Does Yeast Grow Best?
If you want to get a nice head start on the instant yeast, you can stir it into 1/2 cup lukewarm water mixed with 1 teaspoon sugar. One thing important to note, though, is that if you decide to use lukewarm water with Instant Yeast, you will have to reduce the total liquid in your recipe by 1/2 cup to account for the water that you are adding with your yeast. In using most home bread machines, you are best off using 80F water, or whatever liquid, with the instant yeast.
For quick rising, or for instant yeast which will be mixed into the flour instead of added directly with the water, the recommended water temperature is considerably warmer. Colder water temperatures will permit a slower, slower method, which is common for some types of bread, like artisan-style.
Note that different types of yeast are happier at different temperatures, so be aware of the temperature the recipe calls for your water, and use a thermometer until you get a good feel for how the different temperatures will feel for you. These temperatures should be monitored closely, and you will want to make sure that your thermometer is accurate, as you cannot exceed 140 degrees unless you are going to kill your yeast. Experience tells me that, unless your water is so hot it will kill the yeast, you have a much wider range of temperatures that are completely safe for the yeast.
It is important to hit your temperatures correctly, because cold water is not going to let this yeast get going, while warm water kills yeast. Hot water not only will kill the yeast and prevent your bread from rising, it also ultimately will impact how your final product tastes and looks. This means if you are boiling your hot water above 120 degrees F, then it could kill your yeast. When the water temperature hits 140 degrees F. or higher, yeast is completely killed, and when yeast is killed, it is unable to do its function as leavening, regardless of what kind of dough or batter it is added to.
Once your water temperature hits 140 degrees F or higher, this is when yeast is fully killed. Sometimes, when the water is too cold, yeast will produce a substance that interferes with the production of gluten. The fermentation process for yeast also produces water, which, combined with the extra gases, produces a sticky, gassy dough. Because water is not heated sufficiently, the yeast cells lyse and produce glutathione, which bleeds out of the cell walls.
If using active dry yeast in food processor recipes, a common practice is to proof the yeast in a small amount of hot (105-110degF) water, and add a larger portion of cold (or even freezing) water into the food processor once the yeast mixture has been added. If proofing the dough using active dry yeast, 105-110degF should be used for water temperatures. When dealing with fresh (cake) yeast, the proofing temperature should range from 95-100 degrees. Some folks feel yeasted-dough recipes are too finicky, as many state very tight temperature ranges for the water used for proofing yeast.
It is ideal to let dough rise between 80degF-90degF; higher temperatures can kill yeast and stop dough rising; lower temperatures will inhibit yeast activity, thus increasing rise times. Optimal yeast growth occurs around 37degC (98.6degF), but the dough will rise at any room temperature.
It is worth noting that when comparing instant yeast with active dry yeast, we see they have different tolerance temperature limits, with instant yeast tolerating warmer water temperatures compared with active dry yeast. If you are not sure of a yeasts performance, a proofing step with hot water + sugar prior to use can help determine whether or not a yeast is still viable to use. There is a simple way to test your yeast proofing to see if it is still active, add 1 teaspoon sugar and 2 1/4 teaspoons yeast (one packet) to 1/4 cup of warm water. If you would like to test your yeasts health before adding the rest of the ingredients, you can always stir it in some water and wait about ten minutes to see if it has doubled or tripled in size.
What temperature can yeast tolerate?
90°F–95°F (32°C–35°C) is the ideal temperature range for yeast fermentation, and any temperature above this range slows down fermentation. While high temperatures are troublesome throughout the ethanol production process, they are particularly dangerous in the final fermentation stages.
Is 110 too hot for yeast?
The water temperature for proofing should be between 105 and 110°F for active dry yeast. Although 95°F is the ideal temperature for yeast to grow, it isn’t quite warm enough to proof active dry yeast at that temperature. It requires the additional heat to dissolve and activate.