How old is "too old" to resurect liquid yeast

[msa8967]

Found three old Wyeast packets that had manufactured dates of 18, 14 and 11 months ago. Decided to try making 1 liter yeast starters from each of them in order to see if there was much viability in the remaining yeast. Anyone ever try to revive yeast this old with much success? Any tips or advice you have to share for this effort? I am possibly wasting time and DME? Each starter is on its own stir plate.

Thanks,

 

[Calder]

My bet is they all work. You do need to make a starter as the yeast viability (amount of live yeast) will be low and a starter will get them to a decent pitching level. Use a standard starter around 1.035.

I've cultured yeast out of 2 year old bottles before now, and I think the environment in yeast packs is more friendly to the yeast.

 

[iaefebs]

I've had luck with yeast that old. I never tried it on a 1 liter size starter, I have done it with a smaller 300 - 500ml I think you should see some action in 48 hours using a stir plate. The stir plate is the key. After the first 48 hours any step up has been a traditional 24 hour and done step. I should mention that the yeast I used was stored refrigerated. If you found that yeast in something other than your refrigerator I hope you post back your results.

 

[Paul07293]

I think you'll be fine I just did a 500ml starter with Wyeast 2206 dated July 2010. It took a while but after 3 days there was activity in my flask. Next is to step it up in a 2000ml flask.

 

[msa8967]

Well after 24 hours from the initial start and no activity is showing yet for any of the starters but based on your chared comments I am not expecting to see much of anything until day 3 or so. I will update this on Sunday evening if anyone is still interested.

 

[jusware]

I've used yeast over a year old with no problems. I use a 1000mL flask on a stirplate. When I see old yeast go on sale at the local HBS I usually buy it with no hesitation.

 

[thatjonguy]

I just found some (old) limited release yeast so I want to see your progress.

 

[msa8967]

Houston....we have ignition on one of the three engines. This picture is from this morning where I had to replace the foam stopper in the flask. Looks like this reached high krausen so 30-36 hours after pitching the yeast into the starter. No signs of activity yet in the other two flasks with older yeast but I know it is very early.

So for this flask I was thinking of giving it 12 more hours, chilling, decanting and then repitch into a larger starter or just doing this now instead of waiting 12 more hours. Any thoughts?

Do I really need to chill and decant before going into the larger starter?


There is also a picture of my brewing assistant here that works for milk and cookies.

 

[Calder]

Depending on how many live cells you have in the others, you could be waiting a week for it to get started. Give them plenty of time, and if you think they didn't do anything, check the gravity before tossing. I've had starters finish without showing any signs before.

You don't have to decant before stepping up. It is just a more efficient way of doing it and getting more cells.

 

[wheatgerm]

My last batch was a Swarzbeir made with WLP060 that was leftover from a previous batch that i'd made over a year ago. I saved just enough of the cake to fit back in the original WL vial. I dropped the vial into a 2L starter and after about a week it had revived and was ready to pitch. Beer turned out great. One of the best brews I've ever done.

I've also used mead yeast that was almost 18 months old with no problem. Just takes a few days longer to build. I store my yeast at around 35F, so I guess that helps a lot. Who knows.

 

[msa8967]

I think giving the other two brews a week+ is the right idea. Thanks for the reply.

 

[msa8967]

Update on yeasts 2 and 3 at 56 hours. One flask shows a little krausen and the other flask just has some bubbles/foam at the top in contact with the glass.

 

[msa8967]

I chilled each yeast sample and then stepped these up to 2 liters each. The most vigorous one from the first batch shows very little activity at 24 hours but the other two are showing some signs of life as seen below.

For the batch with lots of krausen should I go ahead and chill this again or continue to let it proceed for another 12-18 hours?