Adding Gylcerol for Freezing

thadius856 said:

Excuse me. Glycerin. 99.5% anhydrous, USP.

Updated OP.

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cadillacandy said:

Sorry - that wasn't intended to be rude or anything. I've only frozen yeast a couple of times so I'll defer to an expert to answer your questions. Cheers!

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thadius856 said:

Having trouble deciding how to add glycerine to freeze my yeast. Probably overthinking this one.

Cooked up some starter from a factory vial, so I'm still on fresh yeast in the first "generation", so to speak. I estimated a 1.5b / g DME cell growth rate. Used a fresh ~100b vial of WLP029 with 380g DME, split it 8.25 ways, and pitched 3.25 back for stepping up to a 11 gal batch it went into last week. That leaves me with 5 vials of ~58b cells each which have been sitting in my fridge for a week.

Here's a picture to better illustrate. Can't see the 5th vial hiding in the back.



(Ignore the factory vial of WLP007 in front; it's for next week's IPA starter. The wife brought it home from the brew store without an ice pack and left it out for an hour, and I wanted to cool it quickly.)

Should I:

#1- Pour off half of the liquid from, then add about 25% volume of gylcerine, and freeze. (58b per vial, ~25% empty headspace)
#2- Pour off most of the liquid, agitate back to a slurry, condense down to 3 vials, and add 25% volume glycerine. (96b per vial, ~25% empty headspace)
#3- Same as #2, but condense down to 2 vials. (145b per vial, ~10% empty headspace)

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Brew-ta-sauraus said:

Thadius whats your process for filling your old WL tubes? I currently grow up more yeast than I need per batch and save in an old WL tube as well. I use a flask to grow up in and gettiing it out of the flask and into the tube is a bit tricky. Currently I pour off most of the beer in the flask after chilling. Then a mix the remainaing little bit of beer with the yeast on the bottom then pour into my tube. I chill again till the yeast sinks to the bottom decant off all liquide and add steril water on top. Sorry to high jack your thread but would like an easier way if possible. I also want to freeze my samples for future use. Where did you get the blue lids?

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cadillacandy said:

Are you using GLYCEROL or GLYCERINE?

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BBL_Brewer said:

Glycerol and glycerine are the same thing.

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Brew-ta-sauraus said:

so the question is how many Ml are wl vials?

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BBL_Brewer said:

To the OP. You want to shoot for about 20% glycerine by volume. Cell count is less of a concern as long as you keep track of approximately how many cells are in each vial. I don't know what the volume of your vials are, but for example, if they were 100 ml vials, you would want to add 20 mls of glycerine to each vial. One thing to consider when it comes to celll count is that viability upon thawing will be somewhere in the neighborhood of 25%. So freeze enough cells so that when you thaw and make a starter, you can hit your target pitching rate. Check out my thread on yeast farming and freezing if you want to sift through some more information. There is a link in my signature. The last 4 or 5 pages have a lot of good information. Good luck.

Cheers

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Norie_ said:

This is a great thread on the subject.

https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

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