The Impact of Too-Hot Water on Yeast | Cook's Illustrated (2024)

FAQs

The Impact of Too-Hot Water on Yeast | Cook's Illustrated? ›

We advise patience, not only because such hot water can kill the yeast, which means that your dough won't rise, but also because at the very least it can negatively affect the structure and flavor of the finished bread by encouraging overproofing or overheating during mixing.

Hot. If the water is hot — 130 degrees or above — it can kill the yeast, which means they won't produce any carbon dioxide gas and the dough won't rise at all. (At the very least, hot water can make the yeast work TOO quickly. That gives breads a sour flavor and makes them rise less.)

Regardless of the type of yeast you use, if your water reaches temperatures of 120°F or more, the yeast will begin to die off. Once water temps reach 140°F or higher, that is the point where the yeast will be completely killed off.

If liquid temperature is too hot (above 135°F) it can kill the yeast. If it is too cold (below 105°F), the yeast will not become activated. The liquid should feel as warm as bath water, not hot, on your hand.

Procedure. Boil the glucose solution to sterilise it and remove any oxygen, leaving behind the glucose needed for anaerobic respiration. Cool before adding the yeast (high temperatures will kill it).

However, yeast is sensitive to temperature changes and can exhibit different behaviors under different temperature conditions. Too Hot: Yeast cells can become overworked, leading to the production of undesirable flavors and, in extreme cases, cell death.

Water serves as a solvent and dispersing agent (for salt, sugar, and yeast). Water is necessary for yeast fermentation and reproduction; softer doughs will ferment more quickly than dry doughs.

Fill something with warm water (100–110ºF/38–43ºC). If it's too cold, the yeast won't wake up, and if it's too hot, the yeast will die. (Oh yeah, yeast is alive, FYI.) Add a pinch of sugar to the water.

130° F—140° F (55° C–60° C) Yeast cells die (thermal death point).

Testing your yeast

Step 1: Dissolve sugar in water. Add yeast and stir to dissolve. Step 2: Leave your yeast for 10 minutes. If the mixture rises to double or triple in size, then your yeast is active!

What happens if water is too hot for dough? ›

We advise patience, not only because such hot water can kill the yeast, which means that your dough won't rise, but also because at the very least it can negatively affect the structure and flavor of the finished bread by encouraging overproofing or overheating during mixing.

If a large amount of salt (or sugar, which is also hygroscopic) were to be combined with a small amount of yeast and left for a long time it could, in theory, eventually rob the yeast of water to the degree that the yeast cells would begin to die off.

Yeast is too hot Yeast may have been dissolved in water that was too hot, or the liquid ingredients in the recipe may be too hot, causing the yeast to die. Yeast needs to be warm - not too hot, not too cold. Yeast is too cold If the other ingredients are too cold, it could cause some of the yeast to die.

A Thermometer Is Best, But Not Required

While there's some downside to using water that's a little too cool for the yeast, water that's too warm—between 130 and 140°F—is fatal to yeast. So, if you can't measure the temperature accurately, it's better to err on the side of coolness.

The reaction goes faster at warmer temperatures because more molecules have enough energy to react. The difference is that in bread dough the reaction is controlled by enzymes (organic catalysts) in the yeast.

Lukewarm water always for activating.

Yeast is a living thing and is killed off at high temperatures, around 140 degrees F. This is especially important to remember when you're rehydrating active dry yeast. The water should be lukewarm, 105 degrees F to 115 degrees F, something you can comfortably wash your hands in.

After 15 minutes, you should begin to see foam on the surface of the liquid. If the mixture is foaming, the yeast is still alive, and you can continue with the recipe. If, after 15 minutes, no foam has been produced, then the yeast is no longer active, and you'll need to use a new batch.

Warm water is used to "awaken" the yeast. This means the water cannot be too cool because the yeast needs be active for fermentation to occur. Water that is too hot may kill the yeast, resulting in little or no fermentation. The ideal temperature range is between 25°C and 40°C.