grapecrusher
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When do you need to add yeast nutrient during fermentation and why do you need it?
Yeast nutrient ??
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Pumpkinman
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You can add a nutrient such as Fermaid K or Fermaid O at the end of the lag phase (half the dose), and follow up with the other half around 1/3 sugar depletion.
The short answer to why you need to add a yeast nutrient is (this is copied from the Lallemand web site):
With proper rehydration and handling, the yeast cell population should be at least 4 million cells/mL at inoculation.
By the time the second FERMAID® K addition is made, this population should have grown to about 100 million cells/mL.
It is critical to remember that yeast are still reproducing during the stationary phase, and to do this effectively, especially in high sugar musts, they need oxygen as well as the components of FERMAID® K, including nitrogen (for protein synthesis), sterols and fatty acids (for maintaining alcohol resistance and permease activity).
In addition, the inactivated yeast cell walls in FERMAID® K adsorb medium-chain fatty acids that are toxic to yeast, and provide nucleation sites to help keep the yeast in suspension.
If you've ever smelled rotten egg odors when fermenting, this is indicative of stressed yeast, this could lead to stuck fermentation, just to mention one issue that it can cause.
Adding yeast nutrients at the start of fermentation (end of the lag phase) and at 1/3 sugar depletion greatly helps to reduce this by providing nitrogen and nutrients needed for the yeast to continue to reproduce and grow.
Happy Yeast make a great wine!
I hope that this helps
The short answer to why you need to add a yeast nutrient is (this is copied from the Lallemand web site):
With proper rehydration and handling, the yeast cell population should be at least 4 million cells/mL at inoculation.
By the time the second FERMAID® K addition is made, this population should have grown to about 100 million cells/mL.
It is critical to remember that yeast are still reproducing during the stationary phase, and to do this effectively, especially in high sugar musts, they need oxygen as well as the components of FERMAID® K, including nitrogen (for protein synthesis), sterols and fatty acids (for maintaining alcohol resistance and permease activity).
In addition, the inactivated yeast cell walls in FERMAID® K adsorb medium-chain fatty acids that are toxic to yeast, and provide nucleation sites to help keep the yeast in suspension.
If you've ever smelled rotten egg odors when fermenting, this is indicative of stressed yeast, this could lead to stuck fermentation, just to mention one issue that it can cause.
Adding yeast nutrients at the start of fermentation (end of the lag phase) and at 1/3 sugar depletion greatly helps to reduce this by providing nitrogen and nutrients needed for the yeast to continue to reproduce and grow.
Happy Yeast make a great wine!
I hope that this helps
grapecrusher
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How do u know when 1/3 sugar is gone? My juice is on the 7th day of fermentation .
wineforfun
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By your SG reading.
jamesngalveston
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lets say you start your wine at an sg of 1.100
and you will finnish it off at 1.000
then 1/4 of the sugar will be consumed at about 1.080
1/2 at about 1.050
1/3 at about 1.070 etc.
and you will finnish it off at 1.000
then 1/4 of the sugar will be consumed at about 1.080
1/2 at about 1.050
1/3 at about 1.070 etc.
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