Glenlivet12
Well-Known Member
I've done some reading about yeast banking and figured I'd give it a try. I've done some cell culture at work so I have a familiarity with how cell banking is done in a lab and the techniques used.
I'm banking a pretty common California ale yeast. Its used in a recipe I anticipate making pretty frequently so banking a dozen aliquots of yeast will save me about $7 every time I brew. If I wash yeast from the fermenter to re-use i can get a good five batches out of each aliquot. Its a pretty easy process but we'll see how it goes.
Yeast Starter
First thing you have to do is make a simple yeast starter. You want your starter wort to be easy to digest for the yeast. 1.040 is a good specific gravity for a starter wort. Depending on how big of a starter you want to make there is a pretty easy way to make a 1.040 gravity solution.
Mixing a 10:1 ratio of water to DME will give you something between a 1.035 and 1.040 wort. I added 100g of Muntons light DME to my flask then filled it to the 1000mL mark. I also added the contents of 1 pill of Servomyces to help give the yeast some extra nutrients to bulk up before I freeze them down. I used an erlenmeyer flask for this but you can use a small sauce pot. I put my erlenmeyer flask on the stove and boiled the wort for about 10 minutes( just long enough to sterilize the solution).
After boiling you need to cool it down as fast as possible just like a normal boil. If your using an erlenmeyer flask put a sanitized piece of aluminum foil over the top to keep from getting an infection. If your not using an erlenmeyer flask you can transfer from your pot to a sanitized growler after its cooled down to pitching temperature and put a sanitized piece of aluminum foil over the top to keep out infection (don't put the cap on just foil).
Once the wort is close your fermenting temperature you can pitch your yeast to it.
Now you just have to wait for your yeast to grow. If your not using a stir plate make sure you shake up your wort/yeast solution every once in a while. At this point the yeast need oxygen to help grow and proliferate so shaking or constant stirring on a stir plate is good for them. If your just making a starter for brew day you can prepare it the morning of or night before and pitch when your ready. For cell banking I want as many cells as possible so I will leave mine on a stir plate for about 3 days. The stir plate keeps the yeast cells in suspension giving them a better chance to use up and absorb all the nutrients and sugars giving me the strongest cells and highest cell count I can get.
After about 2.5 days my starter went from a light amber color to a milky peanut buttery color.
After about a day
After about 2.5 days stirring.
Next step is cold crashing the starter, aliquot out the yeast and freezing it down.
I'm banking a pretty common California ale yeast. Its used in a recipe I anticipate making pretty frequently so banking a dozen aliquots of yeast will save me about $7 every time I brew. If I wash yeast from the fermenter to re-use i can get a good five batches out of each aliquot. Its a pretty easy process but we'll see how it goes.
Yeast Starter
First thing you have to do is make a simple yeast starter. You want your starter wort to be easy to digest for the yeast. 1.040 is a good specific gravity for a starter wort. Depending on how big of a starter you want to make there is a pretty easy way to make a 1.040 gravity solution.
Mixing a 10:1 ratio of water to DME will give you something between a 1.035 and 1.040 wort. I added 100g of Muntons light DME to my flask then filled it to the 1000mL mark. I also added the contents of 1 pill of Servomyces to help give the yeast some extra nutrients to bulk up before I freeze them down. I used an erlenmeyer flask for this but you can use a small sauce pot. I put my erlenmeyer flask on the stove and boiled the wort for about 10 minutes( just long enough to sterilize the solution).
After boiling you need to cool it down as fast as possible just like a normal boil. If your using an erlenmeyer flask put a sanitized piece of aluminum foil over the top to keep from getting an infection. If your not using an erlenmeyer flask you can transfer from your pot to a sanitized growler after its cooled down to pitching temperature and put a sanitized piece of aluminum foil over the top to keep out infection (don't put the cap on just foil).
Once the wort is close your fermenting temperature you can pitch your yeast to it.
Now you just have to wait for your yeast to grow. If your not using a stir plate make sure you shake up your wort/yeast solution every once in a while. At this point the yeast need oxygen to help grow and proliferate so shaking or constant stirring on a stir plate is good for them. If your just making a starter for brew day you can prepare it the morning of or night before and pitch when your ready. For cell banking I want as many cells as possible so I will leave mine on a stir plate for about 3 days. The stir plate keeps the yeast cells in suspension giving them a better chance to use up and absorb all the nutrients and sugars giving me the strongest cells and highest cell count I can get.
After about 2.5 days my starter went from a light amber color to a milky peanut buttery color.
After about a day
After about 2.5 days stirring.
Next step is cold crashing the starter, aliquot out the yeast and freezing it down.
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