Freezing yeast question?

[thisisbeer]

This is my first attempt at freezing yeast. I filled up for 15ml vials with yeast from a starter. My question is how dense does the yeast have to be? I put the vials in the fridge and after everything settled the yeast is only about half of the vial. I have heard to much liquid can negatively effect the yeast.

 

[prandlesc]

You should do a search on freezing yeast here and other brewing sites. There is a LOT of information out there, and if you put the vials you've described in the freezer as they are, you might as well toss them now and not raise your hopes of having viable yeast later.

 

[mikescooling]

Their are lots of ways to do this, most know more than me. But you want as dense a concentration of yeast, with very little water. You did add a little glycerin?

 

[thisisbeer]

Yes I added glycerin. I used the Freezing yeast thread here on homebrew talk to learn the method. It said as little water as possible, I am just looking for clarification on that. Should I use a pipette and take the water off the top of the vials then pour one vial in the other? Or will they be fine being about 60/40 yeast/water? I will not toss them as they are in the refrigerator right now and I'm sure are in good health.

 

[mikescooling]

I don't know, but I'll tell you what I do to get as little water as possible. I take a huge meat injector and stick that down into the crashed slurry, suck the yeast out, then into my 50ml vials. Looks like this

 

[thisisbeer]

Thanks. I'll do that next time.

 

[prandlesc]

Yes I added glycerin. I used the Freezing yeast thread here on homebrew talk to learn the method. It said as little water as possible, I am just looking for clarification on that. Should I use a pipette and take the water off the top of the vials then pour one vial in the other? Or will they be fine being about 60/40 yeast/water? I will not toss them as they are in the refrigerator right now and I'm sure are in good health.

I decant my yeast completely (just pouring the liquid off) and then add it to a sterilized 50/50 water glycerin mix, give it a good shake, refrigerate for 24 hours, then freeze. So far all my frozen yeast has worked, and I do create a starter with the thawed yeast to insure that it's viable and vigorous before pitching.

I use half pint jars, and if I had to guesstimate - the yeast is about 25% of the mixture with 75% of the volume being the water/glycerin mix.

 

[mikescooling]

I went around and around about this. Then it hit me, if I want 15-17%glycerin and very little water, just add glycerin to the yeast slurry mixture. Again their many ways to do this.