Yeastman Pure Pitch viability report

[catamount6275]

Dear All,

Hello. I have always wondered about the viability of yeast cultures that are several months old. Most recently I noted on the White Labs website called Yeastman (which I am sure many of us use) the ability to run viability report based on lot number. So I did it and attached the report as well as the initial QC report. Check it out and let me know if you all buy the 94% viability at 3 months. This would certainly change the amount of yeast starters I do (which is almost always) especially if I have 180 billion cells with a 3 month old pack.

Thanks.

Mark

 

[Ward Chillington]

I think that White Labs is taking liberies with Marketing Speak..close and often connotated but different meanings and for brewing purposes, we need both. A I says ..Vitality refers to the state of being alive or strong, while viability refers to the ability to survive or live successfully.
So why the yeast in the package is still alive, the cell count will be less.
I don't recall if they stopped putting the packaged date in place of a QR code. Just over build your starters if you are in doubt

 

[dmtaylor]

A lot of yeast manufacturers package more cells than they will claim. For instance, Lallemand, Mangrove Jack, etc. will say they are packaging 5 billion cells per gram, which should be 50-55 billion per 10-11 gram sachet... but when rehydrated and counted, people find that there are actually closer to 180-200 billion viable cells minimum per sachet. Manufacturers seem to be trying to guarantee success given cell losses due to non-ideal conditions beyond their control during shipping, storage by sellers and buyers, etc.

So, your White Labs package with 180 billon cells at 3 months might be accurate... if in reality they started with 500 billion cells or some such thing and many of those died on the way. They might figure it takes the yeast on average about 3 months to reach your hands, in which case they are right on target. The countdown might not begin for their calculator until 60 days or 75 days or who knows what.

 

[Donoroto]

Yeast pitch rate has an impact on fermentation, and thus beer taste. If you change the pitch rate, the beer will also change, assuming nothing else changes. So if you always make a starter, not doing that will change the beer.