Keeping new yeast: fridge or freezer

[chrisjpryor]

I just bought 4 vials of White Labs liquid yeast because the shipping is more affordable in bulk. I can only brew 1 batch every month. Should I just keep the yeast in the fridge (last one will only be used in 4 months time) and make a starter for each one (I always make a starter regardless), or should I consider freezing the yeast? What if I could only use the last vial in say 6 months, or 1 year?
In other words if I am going to be keeping the yeast for an extended period of time before using it, how does the length of storage time affect my decision to keep in the fridge vs the freezer?

And if I freeze it, can I just add some glycerine to the vial and stick it in the freezer, or should I make a starter with it, wash and then freeze?

 

[RM-MN]

If you freeze the vials you kill the yeast. Refrigeration is what you want to do. You can keep the vial for quite a while in the refrigerator but it will lose viability. http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

 

[NeoBrew]

I assume you have seen this article?

https://www.homebrewtalk.com/freezing-yeast.html

 

[chrisjpryor]

I assume you have seen this article?

https://www.homebrewtalk.com/freezing-yeast.html

I have read the article. What I am unclear on is why freezing will kill yeast in a new vial but not kill yeast cultivated from a starter.

 

[RM-MN]

I have read the article. What I am unclear on is why freezing will kill yeast in a new vial but not kill yeast cultivated from a starter.

You need to add something (glycerin was one thing mentioned in the article) to keep the yeast cells from rupturing. Read the article again so you understand how to sucessfully freeze yeast if you intend to try to keep it that way. Note that you cannot use a "frost free" refrigerator freezer as it goes through a thaw/freeze cycle every so often to get rid of the frost buildup.

 

[NeoBrew]

I have read the article. What I am unclear on is why freezing will kill yeast in a new vial but not kill yeast cultivated from a starter.

I'm sure there is someone on here more qualified than me to answer, but I can't imagine why it would be any different.

 

[chrisjpryor]

You need to add something (glycerin was one thing mentioned in the article) to keep the yeast cells from rupturing. Read the article again so you understand how to sucessfully freeze yeast

Thanks for the suggestion to read it again. (I've read it many times now, I had it bookmarked as a reference). However it still does not explain why I cannot just add glycerin to the vial, as opposed to making a starter and adding glycerin to that.

And if I freeze it, can I just add some glycerine to the vial and stick it in the freezer

 

[Jwin]

I think it is more about the glycerin /water ratio
Several long threads here over it.
And many variations of methods.
If you were going close to a year, I'd build a starter, then mason jar it to build another starter (or 3) off of later.