Frozen yeast report

Physics, chemistry and biology of brewing. The causes and the effects.

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Frozen yeast report

Postby Freon12 » Mon Jan 14, 2002 12:58 pm

My friends at the place (mentioned before to andytv) have agreed to freeze a tube of yeast in liquid nitrogen. I guess the beer I made from frozen yeast was green when I reported off flavor, and has now come correct. Let's see if storage will effect anything. I need input on control media and sugestions.
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Insider Trading

Postby Push Eject » Mon Jan 14, 2002 4:22 pm

Um... did I not get the secret decoder ring for this one?
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Chemical Imbalance

Postby l48shark » Mon Jan 14, 2002 5:03 pm

Well, you've either had too many beers or possibly not had enough. Seriously, check out the original "Frozen Yeast" post from Christmas Day to get the back story on this one. Yes, bad little boys get coal, but Santa brings bad little homebrewers frozen yeast. ;)
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Enlightened

Postby Push Eject » Tue Jan 15, 2002 5:50 am

Ahh... thank you, Shark.
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Coded "G"

Postby Freon12 » Tue Jan 15, 2002 10:36 am

I was avoiding the use of anything that could be considered vulgar by leaving out the name of the place. Sorry if I wasn't clear.(been drinking beer).P.S. They did freeze the yeast. I'll wait 6 months and try to brew with it.
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Plating "control" Media...

Postby Mesa Maltworks » Mon Jan 28, 2002 1:38 pm

If you can tell me what you wish to test for, I can tell you which media to use.
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Storage

Postby Freon12 » Tue Jan 29, 2002 2:22 pm

I have frozen yeast cultures in solutions of 1.035 beer and in sterile water. The water sample strains have died. The beer solution is unstable even at low tempretures but have survived to a point where enough cells can be started and stepped. At tempretures above -80f all strains would not revive well. But below -120f they all revive pretty good. There must be a media that would buffer the cells better at higher more obtainable tempretures let's say -40f for 12 months. This would solve seasonal brewing needs.
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Osmotic Pressure...

Postby Mesa Maltworks » Wed Jan 30, 2002 11:15 am

One of the reasons (among others that are too lengthy to describe here) you are having problems with your proceedures is related to the disequalibrium in osmotic pressure between the solutions and the fluid trapped behind the yeast cell walls. This condition will cause the cell structures to rupture. The beer solution should be avoided due to the difficulty of adjusting for pressure and is unnecessary anyway as they need no nutrition or alcohol protection at these temperatures. The ASBC research I have read relating to cryogenic storage has utilized distilled water that is adjusted to match the osmotic pressure with saline. Now... how to determine how much to use is out of my league. If you are really into this concept, I can find out how this is done, but I think there is a cheaper, safer option. If you are only looking for 12 months of shelf life, simply transfer a single colony of yeast into a slant tube of media composed of agar and hopped wort and refrigerate it at about 35 deg. F. This is what I do in my lab as per ASBC methods and my Siebel training and have never had any problems. I had heard accounts of storing about 1,000,000 cells under osmotically adjusted distilled water and storing at this temperature. When I tried it though, the yeast had serious problems at about 6 months out, so I stopped trying and returned to old faithful. E-mail me if you want me to track down the cryogenic proceedures.

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Yeast storage with glycerol

Postby etbandit » Sun Oct 29, 2006 3:07 am

Try storing your yeast in a final concentration of 30% glycerol. We store bacteria in our lab in 30% glycerol for yrs.
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Glycerin

Postby kount_zer0 » Sat Dec 30, 2006 2:30 pm

I have read that as well...1 to 1 mix of sterile water and glycerin (from your pharmacy is OK)...freeze as low as your freezer can go and try to keep them as cold as possible (like in a block of ice to resist your freezer's defrost cycles).

The glycerine prevents the formation of ice crystals and is probably the easiest cryogenic fluid to obtain.

The paper I read stated that 5 years of storage was obtainable and there were enough yeast cells to re-culture.

I just keep slants cold, and reculture as needed. If I ever go to Belgium or get some other rare valuable (to me) strain, I might consider cryo...

Good Luck!
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