question about reviving really old yeast

[Frostbrewer]

I had two packets of scottish ale yeast that were mfg in apr 2014. Lol i know. Dead as a doornail.

Just for fun i made 1800ml 1.040 wort to toss them in. Put it on the stirplate and finished with a 1.006 FG.

It never had any krausen but did slightly appear to ferment. Looked like mud for a couple days. Obviously something happened and the finished starter beer actually tastes ok. Clean and crisp as opposed to normal starter beer.

I was thinking i should make another larger starter about 3L at least and give it another go.

Its for an imperial chocolate stout. OG 1.086.

Questions:

Will another step be enough Yeast?

Is there a too much dead old yeast and it may make the beer taste bad?

Should I just buy a new pack and forget my experiment?

 

[mtnagel]

If you use yeastcalculator.com, you will theoretically have 58 b cells after your first step. And after a 3L step, you will have 280 b cells, which is just short of the 308 b you need.

But, it's my understanding that you should have started slower to revive the old yeast. I've used year old yeast before, but I usually start with a ~500 ml starter and let it go a few days. Then I'll go to a bigger starter.

 

[SmokeyMcBong]

I don't always revive old yeast but when I do, I like to use lots of yeast nutrient...

 

[Frostbrewer]

Thanks for the info. I will use the yeast calculator moving forward.

I decided to just keep chugging along last night and made a 4.2L starter for the remaining yeast. Og 1.035

Forgot the dang yeast nutrient though. Crap

 

[Frostbrewer]

Mtnagel

What is the reasoning for starting smaller? I had 2 wyeast packs, thats why i went with the larger volume.

Also i didn't find a place in that calculator to enter my OG of my starter wort. Surely that would make a significant difference. Maybe i just missed it

 

[mtnagel]

I've heard it's so you don't stress out the yeast. Basically you were underpitching by at least a half to 75% of what you needed, which stresses the yeast out.

I don't think the OG matters as long as it's not too high or too low. It's never in any yeast calculator that I've seen anyway.

 

[rhys333]

I don't always revive old yeast but when I do, I like to use lots of yeast nutrient...

Well if it's good enough for The Most Interesting Man in the World, it's good enough for me.