
What Temperature Kills Yeast
By: Bob's Red Mill | February 21 2018Making bread is an art. Or perhaps a science. In any case, with breadmaking, there are two kinds of leaveners typically used in the baking process. One is baking soda or powder, and the other is yeast.
Yeast is a live fungal organism made of a single cell. Yeast has over 160 different species that live in us and all around us. The type of yeast that is used when making bread is usually the kind that comes in little paper packets. It looks like beige colored granules that essentially lie dormant until they come into contact with warm water at just the right temperatures.
When the warm water hits the yeast, it reactivates it and “wakes it up.” Then it begins to eat and multiply. The yeast organism feeds on the simple sugars found in flour. As they feed, they release chemicals and gases like carbon dioxide and ethanol, along with energy and flavor molecules.
Not only does the yeast help produce carbon dioxide and ethanol, it also assists in the development of gluten. Gluten is the substance that traps gas bubbles and gives the dough its structure. With no-knead recipes, this process is even more important, because as these gas bubbles move around inside the dough, it helps to push and rearrange the proteins into the necessary structure without any kneading required.
The short story is that without yeast, your bread won't rise properly, and you won't get the same look or flavor that you would when yeast is used.
With dry yeast, if your water is too cold, the yeast will not activate. Or, if they do wake up, they might release a substance that hinders the formation of gluten. Then again, if your water is too hot, you will kill the little buggers and they will be useless.
Typically, hot water somewhere in the range of 105° and 115°F is ideal for proofing dry yeast. 95°F is often recommended for live yeast, but it may not be hot enough at 95°F for activating the dry yeast.
At this temperature, once you pour it into the bowl and dissolve the sugar, it will cool a little bit and be the perfect temperature range for dissolving and activating your bread risers.
Not sure if your water is the right temp? One way to test this is to do the wrist test. Drizzle a few drops of your water onto the inside of your wrist. If it is warm and comfy for you, then it will no doubt be warm and comfy for your yeast too. However, if it is not warm and instead feels hot, it most likely will be too hot for your yeast to survive. By the same token, if it is too cold, then your yeast will simply remain dormant.
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Or is the yeast he is using in the UK different from what we have here in the US?
Water at -4°F means your yeast will be unable to ferment.
Water at 68° to 104°F means that your yeast’s ability to grow will be hindered, and its growth rate will be reduced.
Water at 68° to 81°F are probably the most favorable range for the yeast to grow and multiply in.
Water at 79°F are considered the optimum temperature for achieving yeast multiplication.
Water at 81° to 100°F is the optimum temperature range for the fermentation process.
Water at 95°F is the fermentation temperature that yields the best result.
I cold proof my pizza dough in a fridge at 37 degrees Fahrenheit for 3-5 days. Does this mean I should still activate the yeast at its optimal temperature at the start of the recipe? Or should I be mixing the yeast with cold water at the start of the recipe, to slow down the fermentation process?
Thanks!
i see your article says ... "With dry yeast, if your water is too cold, the yeast will not activate. Or, if they do wake up, they might release a substance that hinders the formation of gluten."
Can you elaborate on the the substance that might hinder gluten formation when using cold water, where the yeast wake up later?
I'm wondering if my potential dough-at-room-temperature wake up solution risks what you mention?
Water at 68° to 104°F means that your yeast’s ability to grow will be hindered, and its growth rate will be reduced.
Water at 68° to 81°F are probably the most favorable range for the yeast to grow and multiply in.
Anything you can send me to advance my breadmaking would be greatly appreciated.