I'm embarking on starting a frozen yeast bank by over growing my next starter. I've combed the internet and have seen most of the articles and videos so I think I'm comfortable with the process. I have a couple of unanswered questions though.
1. How do you calculate yeast viability (%) over time once the yeast is frozen?
2. Since I don't have the ability to count yeast cells, how do I know I've grown enough cells (using stepped up starters from a thawed vial) for a 5 gallon batch with a gravity of around 1.060+/-?
3. Is there a way to approximate yeast count by ml volume?
In terms of yeast bank volume per vial, my plan is to follow the guidelines as described in the attached link which looks to be approximately 5-6ml yeast slurry mixed with 5-6ml of 25% glycerin/75% water mixture per vial for a total of 10-12ml in each 15ml vial.
https://www.homebrewtalk.com/forum/threads/guide-to-making-a-frozen-yeast-bank.35891/
1. How do you calculate yeast viability (%) over time once the yeast is frozen?
2. Since I don't have the ability to count yeast cells, how do I know I've grown enough cells (using stepped up starters from a thawed vial) for a 5 gallon batch with a gravity of around 1.060+/-?
3. Is there a way to approximate yeast count by ml volume?
In terms of yeast bank volume per vial, my plan is to follow the guidelines as described in the attached link which looks to be approximately 5-6ml yeast slurry mixed with 5-6ml of 25% glycerin/75% water mixture per vial for a total of 10-12ml in each 15ml vial.
https://www.homebrewtalk.com/forum/threads/guide-to-making-a-frozen-yeast-bank.35891/
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