Does white labs deteriorate?

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JONNYROTTEN

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just got white labs yeast.on bottle it says it expires in 2 weeks.does it deteriorate with time or is it just as good as the other bottle i have that expires in 2 1/2 months.Lhbs guy says its just as good
 
from the moment they put yeast in a bottle it starts losing cells to age. the 4 month mark on WL products is a best by date. ie use before will be consistent from month 1 to month 4, now if your making starters (you should be) the 4 month date is very arbritary and i've revived vials that were in my fridge for 8mo or more with no problems. the guys who plate their yeast do even better since they have more control over bugs getting into their strains.
 
As long as you make a sufficient starter, you should be fine. I'm not speaking from personal experience, but there are lots of threads here where people have used long-expired yeast and it's worked great (Revvy has lots of posts about that). I have used washed yeast that's a few months old, and it's been fine.

If you're really worried, you can make a starter 4-5 days in advance to make sure it ferments; if it doesn't, then go pick up some new yeast.
 
Bobby M recently did a test on year old store yeast here; https://www.homebrewtalk.com/f13/testing-limits-yeast-viability-126707/

And my LHBS cells outdated tubes and packs of yeast dirt cheap 2-3 dollars each and I usually grab a couple tubes of belgian or other interesting yeast when I am there and shove it in my fridge. and I have never had a problem with one of those tubes. I usually make a starter but I once pitched a year old tube of Belgian High Gravity yeast directly into a 2.5 gallon batch of a Belgian Dark Strong, and after about 4 days it took off beautifully.

I don't know if you know the story of Charlie Papazian's yeast (White Labs "Cry Havoc") or not. He talked about it on basic brewing. The recipes in both Papazian's books, The Complete Joy of Homebrewing and The Homebrewers Companion, were originally developed and brewed with this yeast. Papazian had "Cry Havoc" in his yeast stable since 1983.

He has used it nearly continuously since 83, sometimes pitching multiple batches on top of a cake, sometimes washing or not washing, etc. In a basic brewing podcast iirc last year he talked about how a batch of the yeast after a lot of uses picked up a wild mutation, and he noticed an off flavor in a couple batches.

Now most of us would prolly dump that yeast. Instead he washed it, slanted or jarred it (I can't recall which,)marked it, and cold stored it, and pretty much forgot about it for 10-15 years. He had plenty other slants of the yeast strain, so he left it alone.

Well evidently he came across that container of yeast, and for sh!ts and giggles made a beer with it. Evidently after all those years in storage, the wild or mutated yeast died out leaving behind a few viable cells of the "pure" culture, which he grew back into a pretty hardy strain...which iirc is the culture that White Labs actually used for their cry havoc...because of it's tenacity and survivability.

It really to me, just goes to show once again how really hard it is to f up this beermaking, and that to give the yeast the props they deserve.

If you slant and freeze them, or if you jar them and store them, as long as you make a starter, and provide a sniff test, to catch those rare times, you will be fine.

:mug:
 
It is not that it deteriorates, but that the yeast cells begin to die. The bottle that expires in 2 weeks should definitely be used first. There will be less viable yeast in the older vial and it will benefit from a larger starter before use to build the colony size and get the yeast health back up.

If you go to the mrmalty pitching calculator you can change the yeast mfr date and see how the starter size requirement increases. You should always try to buy yeast with a fairly recent mfr date, or a longer date to expiration.
 

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