7 month old rinsed yeast, to flush or not to flush.

Just bought a new fridge and discovered two quart jars of washed wyeast 1275 dated 4/25/11 in the old unit. Still viable?

You probably could get a starter to take off with it. Is it really worth it?

Make a starter and find out. I just used 7 months old bells yeast, the starer took about 36 hours to take off but it did and my pale ale is now happily fermenting away with that yeast.

Malticulous said:

You probably could get a starter to take off with it. Is it really worth it?

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Yeast are people too darnit!

buy a backypackdet of dry yeast, do a starter and see if it takes off. If not use the backup.

If you make a starter, then the age of a yeast isn't really an issue. When you make a starter, and grow it, you're replicating more yeast to make up for any loss. You're making new, fresh yeast.

Bobby M did a test on year old stored 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And my LHBS cells outdated tubes and packs of yeast dirt cheap 2-3 dollars each and I usually grab a couple tubes of belgian or other interesting yeast when I am there and shove it in my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.
The purpose of a starter is to reproduce any viable cells in a batch of yeast....that;s how we can grow a starter form the dregs in a bottle of beer incrementally...and that beer may be months old.

Even if you have a few still living cells, you can grow them....That's how we can harvest a huge starter (incrementally) from the dregs in a bottle of some commercial beers. You take those few living cells and grow them into more.

I'd give it a go.

I just finished stepping up a vial of WLP007 that had an expiration date of 9-25-10 so it was an 18 month old yeast. The tube had never been opened and was always kept in my refrigerator. I made a first step of 400ml and a second one at 1750ml. . After decanting off the liquid and transferring to two mason jars I ended with around 1 trillion cells, 500 million in each jar. I use a stirplate and both steps were around 48 hours each. If your yeast has been kept at fridge temps I would definitely give the 1275 a go.

Yeast kept that long not only have low viability but very low glycogen levels. The daughter cells health will probably suffer. I'm not saying it can't be nursed back into a healthy culture but the work Wyeast does is certainly worth the price. But then I also think if I have to rinse it it's not worth it. I like to just do a string of six or so beers repitching fresh slurry so the actual cost of yeast is only about a dollar a batch.

OP's post, in my head, translated to:

"Found an ancient civilization of small living things inside a frozen box. Should I try to help them repopulate?"

WELL OF COURSE YES, DUMASS!

You do realize that every brewery produces much more yeast than they can use. It's part of the trash.

the real issue here is how good your sanitation was when you rinsed and packaged this yeast. If it was lab-grade, you have nothing to worry about. If not so much, then maybe spend the $6 on a new vial.

I just used a 6 month old washed 1056 it took over 24 hours to start on the starter and I probably should have stepped it up instead of just doing a 1200ml starter. But it did take off and my beer is fine

-=Jason=-
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There is also the question as to whether the few surviving cells are representative of the original population.

I haven't yet washed my yeast but have 8 or so jars in the refrigerator; mostly Pacman.

I just dumped the slurry, trub and all, into sanitized jars.

ultravista said:

I just dumped the slurry, trub and all, into sanitized jars.

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That's all I do but I like use it within two weeks. Rinsing it hasn't seemed to help viability any so I just try to keep the junk out of the fermenter.