Yeast storage

[ferrarimobile]

I recently used the following process for storing yeast: Yeast bank - Home Brewing Wiki. Though I had a few issues with it, I'm pretty confident that I have some viable yeast from the whole thing. I never did get the type of separation that the picture showed. My vials seemed to have basically two components; nearly clear liquid and opaque solids I assume to be a mixture of yeast and some trub. I used 50Ml vials similar to what White Labs uses for that same reason.

When I added glycerine and shook them, I put them in the freezer packed in frozen veggies and the liquid has not totally frozen. There are five vials and most seem to have a viscous quality to them with some varying degrees of crystalization. Is this normal? I have used basically 25% glycerine 25% water and 50% solids. Should it freeze solid?

 

[Joe Camel]

Is it your chest freezer or fridge freezer? Most fridge freezers are only a few degrees below freezing, about -5C or so. Not quite cold enough to store yeast, worse if it's frost free and they have a warm up cycle. The freeze/thaw cycling will kill your yeast.

If it's your chest freezer, these tend to be set to about -20C, then they might be supercooled. Knock one against the side of the freezer to see if it freezes.

 

[ferrarimobile]

It's a fridge freezer, and the vials are packed in frozen veggies. I don't have room for a cooler in there. I'll have to check the temp. It's set to maximum cold but I don't know the temp.

 

[giligson]

Fridge freezers of the modern day are known as "frost free" not like the kind that you had say 20 years ago that you had to manually defrost every now and again. These freezers stay frost free because the temperature cycles hot from time to time to prevent frost forming. That's convenient but it does not provide the best enviroment for storing food or yeast. This cycling causes ice crystal formation in the freezer contents.

Bottom line - you will likely have some viable yeast but not as much as in a non frost free - ie chest freezer or even bar fridge freezer.

 

[LooyvilleLarry]

Wrap your yeast in one of those flexible freezer things, or inside of one of those freezable coolies. This will keep them cold while the freezer defrosts.

 

[ferrarimobile]

Thanks for that advice. It turned out well. Now I keep them in a small soft lunch cooler packed with freezer packs. I have used a sample and it turned out great!@ After three weeks, I made a successful starter and I have a very active fermentation in about 10 hours. The weizen yeast is producing some strong sulfur smells, but I believe that is normal and I'm psyched to have my own yeast bank. Presently I have Belgian Abbey Ale II, WLP 200, Wyeast Bavarian Lager and Irish Ale. Maybe we can start to share samples at some point. Anyone interested?

 

[ferrarimobile]

No one ever did answer my question: Is the mixture supposed to freeze solid in the freezer?

I have three samples and the last two did not freeze at all, they are simple a viscous liquid.

 

[Joe Camel]

I did answer it, yes it's supposed to freeze. Your freezer isn't cold enough