how long can i save reused yeast

I am planing to reuse the same yeast from my brew fermenting now in about a week or so , but wasn't planing to make a new batch for about 2 weeks. How long can I save the old yeast in my fridge for.


Thanks Dan

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And my LHBS cells outdated tubes and packs of yeast dirt cheap 2-3 dollars each and I usually grab a couple tubes of belgian or other interesting yeast when I am there and shove it in my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 fill 2 nalgene-type bottles with trub every time I empty a keg (they are about 8 ounces). If I use within about 2 months, I just pitch them into the new beer - no starter.

Older than that, I will do a 3L starter to get the yeast active again. It's my rule-of-thumb.

BTW, I reuse saved S-04 and S-05. I know they are cheap, but I'm the product of Dutch ancestors, set in my niggardly ways.

Do you know how many starters I can make from one batch of old yeast?

nabeast said:

Do you know how many starters I can make from one batch of old yeast?

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There's about 2 quarts of trub down there, maybe more. I use about a cup of that trub to innoculate a new 5g carboy, so my answer is.... [drumroll sounds from apron right of stage... ]

8.

I just looked in my fridge. I have some nice looking yeast labeled "pacman October 2009". I probably won't use it, because I'm not entirely sure that it's perfectly fine. But anything less than 6 months that looks and smells good is fair game!

nabeast said:

Do you know how many starters I can make from one batch of old yeast?

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Not sure what you are asking here?

Are you talking about how many generations you could re-use this old yeast or are you asking how many times you could split the old batch of yeast?

I would not reuse more than 5 generations myself.

If you are talking about splitting it and build it up in starters then the sky is the limit.

Yooper said:

I just looked in my fridge. I have some nice looking yeast labeled "pacman October 2009". I probably won't use it, because I'm not entirely sure that it's perfectly fine. But anything less than 6 months that looks and smells good is fair game!

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In this case I wouldn't throw it out, try a starter with it. It may take a little longer to kick off, but if it goes then you have good yeast! Worth a try. I get all my yeast from my local brewery's, it's always fresh and active and free!