Stretching my starter

Hey Everybody,

I wanted to try an experiment with freezing some yeast. I have everything I need, but I wanted to do enough of a starter to make 4 50 mL aliquots, 2 to brew with and 2 to try to freeze. I made up a starter with about a cup of DME in about 900 mL of water. After I force it to settle in the fridge do you think that this will be enough yeast to stretch or should I settle it and add some more DME to build up again.

FWIW this was the most active starter I've made so far. I pitched the vial of White Labs Cali Ale yeast and it fermented up into the arilock on my flask and took about 4 days to ferment out!!

I don't think freezing the yeast is such a good idea. Yeast is alive. Freezing would probably kill them. Just keep them refrigerated.

There are some special procedures you have to follow. If you include gylcerine or DMSO (which is probably not a good idea, seems as we plan on drinking this later) it will keep the cell walls from fracturing when they freeze. They principle is the same for freezing cells that grow in petri dishes. It can be done, but you will lose some in the process, need a big starter when you're done I'm assuming.

This is the page that got me interested.

Ok, it can be done. I still don't think I would want to go through with it. I have re-used yeast from starters, just bottling it and putting it in the fridge. When I need it, I take it out and make another starter. The freezing process just seems like alot of work for nothing. I buy yeast from the LHBS and they have it refrigerated. Seems good enough for me. Just my $0.02.

you should be able to freeze them and revitalize them without an issue if you use glycerol. but you'd want them in a deep freeze (-80C or even liquid N2 temps) if you want them to last a long time... i'd recommend using a smaller aliquot than 50mL, also, so they freeze quickly and thaw quickly.
that being said, i can't think of any good reason to freeze these as opposed to just storing them in the fridge in a bottle or even one of those test tubes...

oh, also....if you have a frost-free freezer, it will cycle and freeze-thaw your yeast repeatedly....so your yeast will die in the freezer... unless you put it in something insulated in the freezer.

??? aren't most freezers (attached to fridges) frost-free freezers? if so, I'm not sure I agree with that last statement, Lou.

-walker

Walker said:

??? aren't most freezers (attached to fridges) frost-free freezers? if so, I'm not sure I agree with that last statement, Lou.

-walker

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well, i suppose if you're freezing 50ml aliquots it won't be an issue. but if you use a small volume, it'll matter.

Jeez people, we're home brewers...if you have to screw with glycerol, DMSO, DMT, or aliquots, then what the heck is the point.

And what/where/why on earth is an aliquot, and why do you need more than one?

El Pistolero said:

Jeez people, we're home brewers...if you have to screw with glycerol, DMSO, DMT, or aliquots, then what the heck is the point.

And what/where/why on earth is an aliquot, and why do you need more than one?

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i agree....like i said originally, just put the yeast in the fridge...
and, for EP (and my own sanity), i'll try to refrain from science talk...

Not hard to freeze yeast. The trick is to get the lil devils to work after you thaw them out. See here http://www.ipass.net/mpdixon/Homebrew/Freezing Yeast.htm and don't be discouraged.

I only wanted to freeze 1 or 2 of the tubes for long term storage, was thinking about making sort of a yeast bank because I had access to the resources, the others would be in the fridge for immediate/short term usage. That being said, I suppose I don't need to do 4, but back to the original question, do you think that that is a big enough starter to do it? I might brew this weekend, then I'll just harvest from the primary, so this could be a 2-pager for naught, but at least it stirred up some interest I suppose

why dont you just add more water? when i make a starter i use 1 cup dme to 3 qts h20. it seems like 1 L h20 to 1 c. dme would be a really high gravity starter, im guessing like 1.120 (1c. to 3 qt is about 1.040 so about 3X's the gravity) you dont want the yeast to be struggling in a high gravity starter...

Ivan Lendl said:

why dont you just add more water? when i make a starter i use 1 cup dme to 3 qts h20. it seems like 1 L h20 to 1 c. dme would be a really high gravity starter, im guessing like 1.120 (1c. to 3 qt is about 1.040 so about 3X's the gravity) you dont want the yeast to be struggling in a high gravity starter...

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what does this have to do with freezing yeast?

Lou said:

what does this have to do with freezing yeast?

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nothing...he asked in the original thread, "is this gonna be enough yeast, or should i add more dme?"

Ivan Lendl said:

nothing...he asked in the original thread, "is this gonna be enough yeast, or should i add more dme?"

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he definitely wasn't asking what people thought about the gravity of his starter, though... he said "After I force it to settle in the fridge do you think that this will be enough yeast to stretch or should I settle it and add some more DME to build up again." -- i don't know where you got your quote from. so his question was more along the lines of whether he should 'amplify' the yeast again in a another starter or if he'll have enough grown up from his original starter (which, btw, he said worked very well). anyway, i don't think a cup of DME in a liter/quart of water is that outrageously high of a gravity. it's a pretty standard starter around here.

if you want more yeast, make a bigger starter. 1 qt h20.+ 1c. dme will yeild less yeast than 3 qt. h20 + 1 c. dme.

More volume=more yeast.

example: 5 gallons of og 1.040 beer will yeild more yeast then 1 qt. og 1.090 beer.

thats all im saying, if he adds more water to the original starter, he will have more yeast to work with...

Ivan Lendl said:

if you want more yeast, make a bigger starter. 1 qt h20.+ 1c. dme will yeild less yeast than 3 qt. h20 + 1 c. dme.

More volume=more yeast.

example: 5 gallons of og 1.040 beer will yeild more yeast then 1 qt. og 1.090 beer.

thats all im saying, if he adds more water to the original starter, he will have more yeast to work with...

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yeah, i agree that he could have made a bigger starter at the beginning. but the original starter is done. he said it went well. you can't just add water to it now. i'm sure we're all on the same page now.
i need a beer.