using old yeast

[sorefingers23]

i have some yeast (white labs and wyyeast) that i bought well over a year ago and never got around to using, I made a starter a few days ago with wlp400 put it on the stir plate and nothing seems to have happened.
When i took it off to settle i only see one layer at the bottom and its not the usually beige creamy layer, it just seem to be the brown trub.
Was my yeast to old to be saved, i was under the impression that as long as a starter was made, using old yeast wasnt an issue.

 

[m00ps]

As long as the starter took off that should be new healthier yeast cells. If you are concerned maybe decant it and add new starter wort and make it go through another cycle

 

[mkyl428]

It depends how it was stored I have revived yeast that was a year past expiration before, with a weak starter, some nutrients, and after stepping up a couple of times it worked great!

here is an article I wrote about it https://www.homebrewtalk.com/using-yeast-past-its-prime.html

 

[mkyl428]

Sometimes it can take a few days to show signs of fermentation, you can try stepping it up again too, it is possible fermentation was so weak, or happened so fast that you didn't see it occur, try stepping it up again and then taste some of the starter to make sure it is exhibiting the same qualities you would normally expect from that strain

 

[sorefingers23]

I have already stepped it up, I started Wednesday night with 1 liter, then added another liter last night with hopes of using it today, but I don't see any signs of fermentation, there's no marks on the flask, no creamy beige layer, I'm wondering if I should hold off on this recipe until I get a fresh yeast vial.
I think I'll make another recipe with dry yeast for today.

 

[j1n]

All the yeast is prob dead.

 

[mkyl428]

I have already stepped it up, I started Wednesday night with 1 liter, then added another liter last night with hopes of using it today, but I don't see any signs of fermentation, there's no marks on the flask, no creamy beige layer, I'm wondering if I should hold off on this recipe until I get a fresh yeast vial.
I think I'll make another recipe with dry yeast for today.

Sounds like a good idea, if you have already tried stepping it up and have not seen any signs of fermentation I wouldn't brew with it, you can taste the starter to see if it has fermented at all, if not I would just toss it, it sounds like that yeast is probably dead.

 

[hvjackson]

If you use a yeast starter calculator you can enter the manufacturing date and it will estimate the number of viable cells (assuming the yeast was stored properly). Then you can decide how many and what size starters it will require to get it going.

But there are almost certainly no live cells left. When I enter 12 months age into the Brewer's Friend yeast calculator I get 0% viability. Liquid yeast really needs to be used within a few months of packaging. At 90 days the viability has already dropped to 35%.

 

[Moebbels]

There are almost always live cells left. The calculator just assumes 0% viability past a certain age so I usually pick a date where it's 1-2% and make a starter based on that. Have used several 2 years and older yeast packs this way.

 

[tim_c7]

I have used (and reused old) wlp400 before. The yeast never got a substantial krausen. The yeast also seems to start and stop thru the fermentation. Check the gravity on the starter to make sure you aren`t actually fermenting.

 

[sorefingers23]

I used a different yeast for my beer just in case, but kept the wlp004 on the stir plate to see what would happen, and sure enough it finally took off sometime through the night on Friday.

Has the yeast been saved or is not worth using anymore?

 

[DurtyChemist]

If it's fermenting it's worth saving. It's creating new cells and I would keep as much as you could for another batch. You probably spent $4 to revive $8 yeast. Next brew you could make a starter and check gravities or direct pitch into some wort and harvest after.

 

[MrVix]

I recently spent over $9 to try to revive a $8 package of yeast. I decided that in the future if the yeast is over a year old I won't waste my time.