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Frozen Yeast?

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berto

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Hi all,
Ive been cultivating up my old bavarian lager yeast. Went to split it this morning, but either somebody turned the fridge down or it decided to get mighty cold overnight. Id already poured off the fermented solution and replaced it with water, but this morning it was frozen solid.
My question is, will this yeast be ok once i defrost it? Or has it gone to the gods?

Cheers, Rob
 

chiller

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Rob,

More than likely the yeast is dead -- however I did almost the same thing with Wyeast 1728 and even though the yeast was frozen I did start up. The beer made from it was fine as were several pitchings from the same yeast over time.

Add it to some starter and hope.

It will take time though to come up. As it is a lager yeast you may stand a better chance.

Try it before you dump it.

Steve
 
J

Jovial_Monk

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Hmmmm from something I read somewhere, any yeast that had sporulated would be OK, but the rest will be dead, hence Chillers experience. The sporulated yeast would give small cells.

In other words, ditch it unless it is the only yeast you have.

Jovial Monk
 

Kai

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Yeast don't sporulate. Though, if they did it would make maintaining cultures mighty easy.
 

morry

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I kinda froze a smack pack one day. It wasnt frozen solid, but parts of it were. The yeast started up fine.
 

chiller

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Jovial_Monk said:
Don't sporulate? quick search on the HBD showed plenty of hits talking about yeast sporulation. E.g. http://hbd.org/hbd/archive/2750.html#2750-15

JM
I don't particularly wish to buy into this discussion but what the heck.

JM you sent us to this link as a reference source:

>"Encylopedia of Beer", it says under "Lager" (talking
>about ale yeast), "If the temperature of the ferment drops much lower
>(than 58F), the yeast goes into a state of hibernation, building a cyst
>around itself in a process called sporulation"

The quote you sent us to JM refers to Ale yeast and when we read further we find --

Compare to the introduction to the ASBC's yeast sporulation test
procedure: "Yeast sporulation is useful for identification of some
species of wild yeast, because lager yeast sporulates poorly, if at
all".

When we read of the actual test conditions it seems that frozen yeast may not be an ideal condition for sporulation to take place.


Again this is from your quoted source --

To induce sporulation the yeast are grown on an agar poor in sugar
and rich in acetate (just sodium acetate and agar in the procedure
mentioned above). After growth on this medium, a smear is prepared and
stained with malachite green, then counter stained with safranin.
Vegetative cells take the safranin and appear red. Asci (sort of lozenge
shaped "pouches") stain green and contain from 1 to 4 spores.

I don't doubt yeast sporulate as indicated from this quoted source however it seems that under homebrewing conditions it is extremely unlikely to occur.

Steve
 

cubbie

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Too get it back on track.

I have just encountered a similar problem, my CC froze 2 days out from bottling, I was going defrost it and pitch some new yeast and then bottle. does this sound valid? If so should I pitch then bottle straight away or should I wait a day. I have a liquid yeast that a smacked today, so I am hoping to get a new brew on by wednessday (my first liquid)

Also if a pitch a new yeast do I still need to prime or will there be enough fermentables in the starter?

Cheers,

Cubbie!
 

Gulf Brewery

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Hi all

I think we are missing a point about yeast here - yeast reproduces by budding, not by creating spores. Freezing yeast cells ruptures the cell walls, so unless precautions are made when freezing yeast (using someting like glycerine), freezing yeast will kill them.

Pedro
 

Gulf Brewery

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cubbie said:
Also if a pitch a new yeast do I still need to prime or will there be enough fermentables in the starter?
Cubbie

An active yeast will use all of the sugars in the starter fairly quickly. You will need to add more sugar to the beer for priming.

Cheers
Pedro
 
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