using old yeast

[Frostbrewer]

I have two packages of scottish ale yeast that is right at 6 months old. Wyeast

I have the capabilities to make a very large starter 5L flask and stir plate.

Should I roll with it and make the starter or toss the yeast and buy new?

 

[flars]

The yeast should still be good if it was taken care of. I would start out with a 1 liter, 1.010 OG starter because of the yeasts age. If the starter performed well, step it up to the cell count you need.

 

[bigmick91]

6 months is absolutely nothing if kept correctly. Old yeast might take a little time to get going but will work absolutely fine. Yeast is a fungus so will replicate by mitosis (some reproduce via a process called budding but lets not split hairs) meaning its possible to get a full brew from a single yeast cell. Dried yeast if stored properly will last pretty much indefinitely. If in doubt i sometimes make a micro culture in a jar with a little sugar water to check. So far I've never had one go "off" per se

 

[Frostbrewer]

Makes sense, thanks

Frostbrewer

 

[bstacy1974]

I did a porter in July. I called it Left Overs Porter. All except one ingredient was left over from other brews.
My yeast was one package of Nottingham, 1.5 yrs expired and one package of S-04, 1 yr expired. OG was 1.078. FG was 1.024. A bit high on the FG but its a damn fine beer. Didn't rehydrate, just sprinkled it on top of the aerated wort.

 

[Fermented_minds]

I have two packages of scottish ale yeast that is right at 6 months old. Wyeast

I have the capabilities to make a very large starter 5L flask and stir plate.

Should I roll with it and make the starter or toss the yeast and buy new?

Definitely make a starter and you'll be fine. The culture is still a pure culture, and the only thing that's really changing is you're getting some cell death and degradation. Make a starter and you'll propagate the healthy yeast quite fast. Since the viable cell count is pretty low,I'd recommend a couple steps. Maybe make a 1L starter to get the healthy yeast rolling, and from there crash/decant and pitch that yeast into 3-4 L. Should have a TON of yeast after that! Good luck!

 

[Kblandfo]

Here is an interview with a brand manager with Wyeast. He is asked and talks about using older yeast. Its a decent read. He states somewhere that he has used old yeast with positive results.

http://byo.com/stories/issue/item/3164-live-facebook-chat-with-michael-dawson