Yeast experiment - way too old yeast

[DrWill]

So, in my fridge today I found a vial of American Ale II (from Wyeast 1272) that I prepared from a batch of stout using the most basic of techniques: essentially I washed a slurry, got a good plug of yeast, and sealed it into an old White Labs vial that had been sanitised (not sterilised.) It was then thrown into my fridge. Here's the kicker:

It's been there since 29 July 2012.

As a gift, I received an Australian kit & a kilo can of hopped extract. It seems like the perfect beer with which to conduct an experiment. So I've prepared a small starter (330ml of 7.2°P wort) and tossed in the yeast. I should brew a batch of porter with it in a few days. I will keep you apprised.

 

[ArcLight]

Make a bigger starter, not 330 ml.
Let it ferment out over the course of at least a full week, if not 2 weeks. Give it the extra time for any viable cells to multiply.

I would not use it after just 3 days because there are so few viable yeast cells.

 

[DrWill]

Make a bigger starter, not 330 ml.
Let it ferment out over the course of at least a full week, if not 2 weeks. Give it the extra time for any viable cells to multiply.

I would not use it after just 3 days because there are so few viable yeast cells.

Sorry, to clarify, ArcLight, the 330ml is the first step, not the last.

Thank you for your input.

 

[EarlyAmateurZymurgist]

DrWill is taking the right approach. A multi-step process is called for when using an old yeast culture. A brewer should never pitch a small amount of viable cells into a large amount of wort.

 

[ArcLight]

DrWill is taking the right approach. A multi-step process is called for when using an old yeast culture. A brewer should never pitch a small amount of viable cells into a large amount of wort.

Why not?

How is it different from making a small starter, then stepping it up with a larger one?

The stepping up is usually done if you can't use a full volume because your flask isn't large enough.

 

[DrWill]

Why not?

How is it different from making a small starter, then stepping it up with a larger one?

The stepping up is usually done if you can't use a full volume because your flask isn't large enough.

I'm not sure who gave you the idea that stepping up is done because you don't have a big enough flask. If you don't have a large enough flask, stepping up isn't going to help.

Pitching a small sample into too large a volume of wort can have detrimental effects on the yeast in terms of selection. I recommend Jamil Zainasheff's yeast starter FAQ, which can be found here.

 

[ArcLight]

>.I'm not sure who gave you the idea that stepping up is done because you don't have a big enough flask. If you don't have a large enough flask, stepping up isn't going to help.

Stepping up is exactly what you do if your flask is too small.
(i.e. you need more yeast than your flask holds.)

For example, for making lagger, with a 2 liter flask, you make the starter, put it in the fridge to settle, decant the spent wort, make a new starter and pitch the now larger amount of yeast.


The reason you make a small starer is when you are culturing yeast and have a tiny amount of yeast, (in the millions), grown from a slant. You then make a small starter to force the yeast to eat all the different sugars in the wort. Then you step up.

Stepping up is for either tiny amounts of yeast, or if you need a large amount of yeast.

 

[DrWill]

I have proper equipment so I've never had to worry about that. That's not why I'm stepping up and it's certainly not the only reason to step up. It would seem to be a lot easier to actually get the equipment you need.

 

[DrWill]

Well, an update. Yeast came back okay and fermented well. I don't think I got the ideal level of propagation and I might have been well advised to take even longer building I up, but it was viable and gave me a nice clean ferment.


Sent from my Rotary Phone using Magic.

 

[Jayhem]

Good to hear. I used 8 month old washed yeast in my last IPA and made a 2-step starter and was worried about underpitching but it was highly viable and I actually overpitched because I had krausen on the beer wort in 2 hours!