Can I revive this old yeast cake?

[jpoder]

so I brewed a 1.050 belgian stout meaning to grow up a large quantity of yeast (WLP 530) to provide a decent pitch for a quad (1.093). I was planning to brew the weekend after bottling the stout, but alas, life got in the way, and now, about 6 weeks later, the cake is still sitting in the carboy @ ~ 60 degrees F(I dumped in ~ 1 gallon of pre-boiled water after racking/bottling). Can I / should I try to revive this yeast?

I assume if I should try, I would think attempt to properly wash the yeast, take a sample and grow up a new starter.

If I dump the cake and buy a new vial, I probably delay brewing at least 2 more weeks.

thoughts?

 

[Shinglejohn]

I say go for it.

 

[Revvy]

I'd say if it wasn't sitting under beer for 6 weeks then it's probably mutated into something nasty....I'd make a starter and see how the yeast is before I pour 5 gallons of wort onto it.

 

[waddsworth]

Yeah, proof it with a starter. No need to risk wasting an entire batch of beer PLUS the time spent on brew day for a few bucks worth of yeast.

 

[jpoder]

UPDATE:

Looking back at my brew logs, it was more like 4 weeks rather than 6, and there was some beer (and some water) on top of the cake roughly half a gallon of beer and half a gallon of water.

I washed the yeast cake, and took about 1/3 of it and put into a growler with some starter wort.

at the same time, I started to grow up another starter from some bottle dregs of the beer that the cake grew.

Both took off pretty well. the growler is now overflowing with yeasty kreusen, and the dregs/starter is growing on this step-up from bottle dregs. both have the same beautiful belgian flavor profile (fruity, yeasty, bready, belgian-y) that I know and love from the Westmalle yeast... Horray! So, brewing tonight (The Pious New world recipe (Westy 12 clone)...search the forum for it!) and probably going to use just the growler. I'm very excited!

 

[maida7]

Even if you stored it in the fridge there would be a lot of dead yeast in there. At 60F for 4-6 weeks with no (or very little) beer, the yeast will consume their reserves and die. It could have some serious autolysis. Open it up and take a big wiff. If it smells like ass, toss it. It it still smells fresh, the make a starter and see how that goes.

Personally, I'd buy new yeast and grow that up with some starters.

 

[theredben]

Even if you stored it in the fridge there would be a lot of dead yeast in there. At 60F for 4-6 weeks with no (or very little) beer, the yeast will consume their reserves and die. It could have some serious autolysis. Open it up and take a big wiff. If it smells like ass, toss it. It it still smells fresh, the make a starter and see how that goes.

Personally, I'd buy new yeast and grow that up with some starters.

Not sure if you realized he updated his post by saying that he made a starter. Making a starter allows the surviving yeast to digest the dead yeast cells, removing the autolysis factor. That is what yeast nutrient is after all.