Liquid yeast viability.

Share your experiences of using brewing yeast.
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PeeBee
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Re: Liquid yeast viability.

Post by PeeBee » Mon Sep 14, 2020 1:22 pm

MickJ wrote:
Mon Sep 14, 2020 9:27 am
I have just pitched a Wyeast smack pack and don't think it's viable, out of date by a two months and was kept in the fridge at 5*c which should be OK but I just think it will be good..

Pitched Saturday night and no change in SG on Monday night...
It's a Fullers London Pride with 4120g of grain so willing to dump the lot if required..

Question is if the yeast was off will it affect the taste if I pitch S-04

Michael
A two month out-of-date smack pack can be resurrected. But I'd treat it to at least a four step starter (over four days), I think the idea you can "smack" even a 3 month old pack (never mind 8 month old) and expect it to kick off 20-25L of wort is cloud cuckoo land. And what "f00b4r" says; off flavours may have started to develop, but it needn't be bacteria, the dead yeast cells that inevitably arise could start spilling their guts into the wort (autolysis).

Pitch the S-04 if still no signs now; even if the smack-pack does work, it could be a few more days before you know.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

Rob_85
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Re: Liquid yeast viability.

Post by Rob_85 » Sun Oct 11, 2020 9:57 am

Bit of an update - took me a while to get round to using these yeasts!

I used A15 Independence in an OG1060 BIPA in August (8 months old), and A18 Joystick in an OG1045 golden ale in September (9 months old).
Both were propped up in a 1 litre starter. Both were fermented at 19C and climbing out of the blow off tube within 24 hours.

I didn't get ant autolysis or stressed yeast off flavours so it seems they were perfectly healthy and viable after all that time.

At the time I originally posted here I also sent a message to Imperial, they replied and were helpful...
"Our shelf life on all pouches is 4 months from manufacture date, as all strains reflected viability of at least 90% until that 120 day mark. Beyond that, viability can vary significantly between strain and is also impacted by temperature fluctuations, handling, transit, etc. Unfortunately those online calculators are not great at taking those additional variables into consideration.
However, you can still count on some viable cells in the pouches. Your best bet will be to build some starters and be sure they take off before pitching to your batch."

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PeeBee
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Re: Liquid yeast viability.

Post by PeeBee » Sun Oct 11, 2020 8:36 pm

Good!

Just don't make a habit of it 'cos one day you will get bitten.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

Greg
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Re: Liquid yeast viability.

Post by Greg » Fri Oct 30, 2020 8:51 pm

Just to add my experiment, I had a pack of WLP005 in the fridge that went past it’s use by date of 03/07/2020 which I’ve done a 300ml starter for 3 days ago, it took 36 hours for any signs but it was there! Poured another 300ml in 12 hours ago and it’s bulging the cling film covering now. So glad I read this thread and decided to revive the yeast. Now to decide what to brew 🙂

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Re: Liquid yeast viability.

Post by IPA » Sat Oct 31, 2020 8:03 am

I have revived yeast from a bottle of beer that was 40 years old and still use it it to brew. Yeast survives best in beer.
"You're not drunk if you can lie on the floor without holding on." Dean Martin

1. Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in sideways, thoroughly used, totally worn out and loudly proclaiming... "f*ck, what a trip

It's better to lose time with friends than to lose friends with time (Portuguese proverb)

Alone we travel faster
Together we travel further
( In an admonishing email from our golf club)

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