Reuse old yeast

[NewkyBrown]

I have a vial of white labs yeast which is a month from its use by date. I am going to make a starter and use it in a beer this weekend. Would it be ok to harvest some from the starter to reuse in another batch or, as its old, just pitch it all and buy new.

I am not trying to save money it's just that I can't get this yeast locally and don't like mail order yeast in summer.

Cheers

 

[Kerrbrewer]

You can harvest from the starter or your brew after you rack it out of the fermenter. I personally dont like messing with my starters, I wash yeast after its done.

 

[flars]

No problem at all harvesting some yeast from your starter. Here's a pitch rate/starter calculator with an overbuild option just for that purpose.
http://www.brewunited.com/yeast_calculator.php

You can also harvest the yeast from the primary after your beer ferments out. Don't rinse it though. Just pour it out into a jar. There is a sticky on this method.
https://www.homebrewtalk.com/showthread.php?t=579350

 

[oujens]

As long as it ferments good, I say harvest it. Should be a new generation of healthy yeast.

 

[Brew_G]

Absolutely.

A couple months ago, I split a starter of Wyeast 1010 that was well over a year old (probably 18 months or so). I'm fermenting an American wheat with it right now - took 5.5 gallons of 1.052 down to 1.009 in four days. Rippin'!

 

[NewkyBrown]

Thanks for the input.
I just used mr malty calc (which I should of done prior to creating this thread) and it says the yeast vitality is 10% and that I would need 6 packs in a 2.6 liter starter on a stir plate. Seems wrong to me. The yeast technically is still in its use-by date. Do you think i should just use one pack in a large starter or buy fresh?
Thanks again...

 

[flars]

Thanks for the input.
I just used mr malty calc (which I should of done prior to creating this thread) and it says the yeast vitality is 10% and that I would need 6 packs in a 2.6 liter starter on a stir plate. Seems wrong to me. The yeast technically is still in its use-by date. Do you think i should just use one pack in a large starter or buy fresh?
Thanks again...

Mrmalty under estimates yeast viability. Use Brew United for a better estimate of viability.

 

[jekeane]

Mr. Malty is my go to calculator but it is super conservative relative to dates in my opinion...

I almost exclusively harvest from a starter now a days. However, with an "expired" yeast I would reuse slurry rather than harvesting from the starter. The starter has the potential because of the age of the yeast to be on the lower end of your desired pitch rate and harvesting from the starter could hinder your batch fermentation. If the yeast does it's job in the fermentor you know it is good to harvest.

 

[Brew_G]

Thanks for the input.
I just used mr malty calc (which I should of done prior to creating this thread) and it says the yeast vitality is 10% and that I would need 6 packs in a 2.6 liter starter on a stir plate. Seems wrong to me. The yeast technically is still in its use-by date. Do you think i should just use one pack in a large starter or buy fresh?
Thanks again...

You can start it slowly in 750 mL or so of 1.030 wort, then step it up a couple times and you should be golden...unless the pack was improperly stored at some point and those last really strong cells didn't make it.

Of course, you don't have to do that at all of you have the ability to get another pack of yeast, but I like the challenge that my "clinically dead" yeast provided me.