nonviable yeast

So I have been collecting, cleaning, and freezing yeast since I went AG and I was starting to get a nice little collection. I was planning on using one in my upcoming batch but I wanted to check it to make sure everything was good to go before I just tossed it in my wort.

So I made a starter and I got no action... none

The way I have been storing my yeast is by using that %50 yeast, 25% water, 25% glycerin technique that I believe I read about on here. The one thing that I have noticed is that the yeast have settled to the bottle of the tubes and the glycerin and water are sitting on top. I thought the yeast were suppose to remain in suspension with the glycerin and this is what kept them from actually freezing. So I guess they froze and it killed them. But my question is...how do I keep this from happening?? How do I keep the yeast in suspension in the freezer??

Somebody? Anybody? please help

I'm not sure. I haven't had this problem with the two batches I have frozen.

Did you shake up the vials REALLY good to ensure the water, glycerin and yeast were mixed well? If they froze quickly, it seems unlikely that the yeast would fall out of suspension so quickly. Alternatively, are you sure it is yeast at the bottom of the vial and not just break material/trub?

Second, freezing vials on their side (instead of standing them up) should make it harder for them to separate much).

Third, if neither of these work, I would check your technique. Are you failing to rinse sanitizer or something? With the small volumes of yeast you are using, there is increased risk that they might be affected by things like sanitizers.

If you figure things out, please post back so we know what went wrong. I know I am going to be watching more carefully now for this problem.

They should freeze with the glycerin, the glycerin just prevents ice crystals from forming and puncturing the cell walls of the yeast cells. I think FlyGuy is right, you didn't mix them well enough, the glycerin is tough to get mixed.

I would guess though that even if the yeast froze in water, there would still be some viable yeast, what size/kind of starter did you use? Stirring? I'd keep mixing it and give it time, the yeast replicative cycle isn't super fast, it may take a week or so for it to get going depending on the number of viable cells you transferred to the starter and starter size.

edit: also, if you have a frost-free freezer, the repetitiive freeze/thaw cycles can kill the yeast pretty rapidly.

ColoradoXJ13 said:

edit: also, if you have a frost-free freezer, the repetitiive freeze/thaw cycles can kill the yeast pretty rapidly.

Click to expand...

Good point that I forgot to mention. I do have a frost-free freezer, so I solved this problem by storing all my vials in a small cooler between two ice packs. It is enough to keep everything cold and well frozen between defrost cycles.