safale us-05 rehydrating question
- Thread starter Dumpsterboy
- Start date
Help Support Homebrew Talk:
The yeast does not care at all about the minerals, but it does care about osmotic pressure.
As there are no ions in ro or distilled water but lots of them inside the yeast cell, the water constantly tries to flow into the yeast cell till the ion concentration outside of the cell matches the inside of the cell concentration.
As this is not going to happen, the cell explodes instead.
In other words, you have the wrong reasoning but doing the right actions, so keep going using spring water, never use ro or distilled water for rehydration as it kills the yeast.
REPO
Well-Known Member
As I am a noob, this is great advice!
Nebraskan
Assoc. Winemaker
Home winemaking I never hydrate yeast. I have tried 2 different tanks at the winery for adding yeast. Same juice. One had yeast added (amount) straight from the package, the other tank yeast hydrated with 100 deg. water and allowed to cool before adding. Both tanks started up (same lag phase) at the same time and both finished dry. So not sure about all the fuss and bother.
Also, yeast is a living growing organism. It is a fungi that buds and releases emzymes when it buds or splits to 2 yeast cells. Those enzymes are responsible for converting sugar to alcohol in a sort of step process. Yeast don't actually eat, or consume a lot of sugar, but convert it by living. They are really after the O xygen molecule that is in sugar that is missing in an aerobic state of the juice with all the O2 used up. Only when the juice is anaerobic (without oxygen) does real alcohol production begin. It is not like adding a teaspoon of salt to your cooking recipe. You may introduce millions of yeast cells at inoculation (pitching yeast in beer terms) but will end up with billions at the end. You cannot over add yeast since is produces more of it's kind in the liquid. The alcohol is a byproduct that is toxic to yeasts and in a sense they are creating their own poison by mass growing. So, no, you won't taste too much yeast if done right, in fact, should not be a factor.
Also, yeast is a living growing organism. It is a fungi that buds and releases emzymes when it buds or splits to 2 yeast cells. Those enzymes are responsible for converting sugar to alcohol in a sort of step process. Yeast don't actually eat, or consume a lot of sugar, but convert it by living. They are really after the O xygen molecule that is in sugar that is missing in an aerobic state of the juice with all the O2 used up. Only when the juice is anaerobic (without oxygen) does real alcohol production begin. It is not like adding a teaspoon of salt to your cooking recipe. You may introduce millions of yeast cells at inoculation (pitching yeast in beer terms) but will end up with billions at the end. You cannot over add yeast since is produces more of it's kind in the liquid. The alcohol is a byproduct that is toxic to yeasts and in a sense they are creating their own poison by mass growing. So, no, you won't taste too much yeast if done right, in fact, should not be a factor.
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